The more I learn about the old telephone system, the more wild it becomes. The sheer complexity of it all. It’s incredible it ever worked in the first place.
@@mutestingray Haha, yep. All done with electromagnets, springs and pieces of metal. And with the correct maintenance they’d reliably do millions of cycles. So far as the (UK style) Strowger equipment went there were only three generations. Up to 1936, 1936-1956, then 1956 onwards (dates are approximate)
A cut cable didn't always cause lines to be shorted, BUT, if a cable got water into it, that would definitely cause a mass short. a 5ESS would protect itself by turning the battery off to those lines fairly quickly, but a old EM switch would just keep pumping battery into the wet short until it turned into a green gooey mess from electrolysis, especially if it was a splice that got wet. If caught in time, a ticket was ordered for a CO tech to remove the heat coils in the range of pairs that was affected by that wet cable, until it was attended to by a crew ( which as a cable splicer I was tasked to do for larger cable outages)
@@Telephonebill51 HA! Depending on, a LOT of variables, air pressure may be a blessing, or a curse. Most times it may keep water out of a small leak in an underground cable, but, it could also cause a poorly wrapped temporary closure ( not used a lot since the 1980's, because not many could put them on properly anymore) to blow out, causing a MUCH larger leak that may also cause a splice to become wet quickly if water came up in a manhole run due to a flooding rain. And then, a flooding rain has caught more than one tech ( not me, thankfully) off guard and unable to close a splice they were working in before water got into it.
I had a friend at Mich Bell who was in charge of an older office in a neighborhood with a lot of pulp cables. When it rained hard he had to hurry into the office to pull the coils in the known worst cables or the switch would go down.
Oh I didn't think of that. If a modern data wire gets wet, Ethernet or whatever, it wouldn't do that because there's no battery. And of course fiber optics are basically waterproof although.
Another reason for phones going off hook, especially in the Seattle area, is earthquakes. The shaking will knock phones every which way including pay phones (yes I'm that old to remember what a pay phone is). The guides for post disaster actions ask if you find a phone off hook hang it up. This helps clear the the jam faster allowing service to come back faster.
Reading this comment thinking that would be a good uncle Sam poster. you know the one with the finger pointing at you to join the army or in this case put the phone back on the hook.
@@robertgift There isn't enough call processors to handle all of the phones. Every phone off hook is asking for a call processor. At the time I saw that message payphones would operate without coins. so you could dial emergency services.
An interesting, seemingly meaningless action until you know how things work. Talking about pay phones, reminds me that here in Brazil, phones were a weird deal way into the mid to late 90s. It costed a heck lot to have a landline, not even talking about mobile networks, and thus very few people had them at all. Like, I mean it costed about the price of a cheaper brand new car to install the line. To solve the communication issue, people would often learn about the closest pay phone number and call THAT thing instead, so that someone on the neighborhood would pick it up and pass the call to who it's intended to. It's funny to think of a public pay phone ringing out of nowhere, but they are indeed phones like all others and people here used them as such. Back when I was a kid I had a pay phone card with me all the time in case I needed to call home (by that point, phones were already common but not common for kids in the early 2000s to have had cell phones).
@@randycarter2001 - My dad was a telephone man, and when we had to make an emergency call on a camping trip without a coin, my dad took a sharp pin and put it in the carbon mic and touched it to the body of the payphone and up came the dial tone. He was able to get the operator to place a call for us. Those old pay phone circuits were Ground Start. Those were the days when the pay phones had three holes 5¢ 10¢ and 25¢ and generated a single tone for each coin. :) Unlike later systems that generated two 66ms pulses of 1700/2200 for dimes, one 66ms pulse for nickles, & for the quarters five 33ms pulses with 33ms rests of that same 1700/2200 mix. Anyone for RedBox my good man? LOL
Back in the 80s, there’d be times I’d be visiting my grandmother and she was still leasing an old rotary phone from the phone company. Sometimes the handset wouldn’t sit back properly and eventually the beeping would come on. Once I went to put the handset back down but the beeping stopped. I assumed it fixed itself but then I heard talking. The operator came on asking if anyone was there. I then hung up. We were in Southern California served by Pacific Bell at the time. After she passed, my dad tried to return the leased phone back to SBC and they didn’t know what to do because they stopped leasing phones a long time ago.
In France they never stop the leasing even if they stop maintaining theses phones years ago (like 1995) there is a bunch of grandma still paying for theses and when it broke they just tell, we don't lease phone anymore, you must buy a new one. They even rise the fee from 1€50 to 2€ /month. They even still send fee to some people that close the line, but they still send the bill for lease.
@@FinnleysAudioAdventures Must be the grey hair here! Sorry bout that, but yes it was meant for Sarah. Guess that shows I don't know how to send a comment to a presenter - hopefully she gets this!
What happens if you leave your phone off the hook? Well...from first hand experience I can say that the first three days are absolute bliss and unimaginably peaceful. Then, after about four days, your girlfriend gets worried that she always gets a busy signal so she automatically assumes the mob came and attacked you leaving you lying on the floor in your basement (because that just makes perfect sense). Next your she has her stepfather drive two hours each way (she doesn't have the time to take the bus herself) to knock on your door and ask if your ok. When he points out that everyone gets a busy signal you go and look at the phone and realize that it had been pushed under the couch and the cat had knocked it off the cradle.
Off topic but when I was a phone phreaker in the 70's, we had numbers that were like permanent busy signals where you could talk loud and hear and talk to others. Of course the loop lines were more fun!
When my Mom had a landline she would take it off hook every time she went to take a shower, so that she wouldn't feel pressured to jump out and answer the phone if it rang. I never considered the possibility of a CO worker taking action on that.
@@nickwallette6201 As kids we learned not to mess with the operator or 611. They knew where you lived. Everyone else you could swear at with impunity! Just to be safe we left the police alone too. And radio / TV stations, they had tape recorders.
And eventually maybe the CO guys figured it out that Mrs Grable was taking a shower. 😂 I was taught long ago if I wanted to prevent the phone from ringing to dial my number. I’d hear busy signal and now I know that a sender was released for someone else to use.
Anecdote; As a 70’s kid in Norway, I’m pretty sure we didn’t have the “holler” step in the fault sequence. The older generation electro-mechanical switch (small town, possibly Strowger from early 30’s?) would cut the dial tone, then go silent (line noise, ghost audio). Not much happening at the subscriber end, as I recall. Our local office was digitised quite early (just prior to 1980?), and this equipment simply switched to a busy-signal, maybe with a slightly different timing. Hard to know what people used to do, but the phone book (part that nobody read, except nerdy me) asked people to pull the plug - please don’t off-hook. Thanks for another great video! 😊
@@VarionJimmy Me too (Sweden), Leaving the phone off-hook was the easy way to not get disturbed. Much easier than running around and pulling the plugs of all four phones in the house! Imagine all the trouble cards and alarm bells we would have caused if it were in the US!
When I was a kid, our town was served by a Bell SxS office. I believe the permanent signal tone was a wailing noise which varied in pitch which customer’s called the crybaby. The SxS office was interesting because there were enough microphonics, crosstalk or whatever going on, that you could usually hear pulsing, relay clicks and various noises. The background noise was more noticeable before the called party was cut in, but it was still audible in conversations. Crossed speech was unusual, but sometimes indistinctly audible. The town cut over to ESS in July of 1976, and it was a bit disconcerting because all that background noise disappeared all at once
The first time I heard the "crybaby" tone, I was falling asleep to one of Evan Doorbell's recordings. It made me about jump out of bed, it was so startling. I'm sorry I missed the days of interesting tones and background noises on landlines, but I'm not sad to have missed that one.
I remember you still heard a lot of crosstalk and random noises when the recordings came on though, like the "if you'd like to make a call, please hang up and try again..." message. I wonder why that was.
@@viktorakhmedov3442 Changing the topic slightly, I had an AT&T announcement set back in the 1980s. It was heavy - like 20 pounds. The thing was full of germanium transistors and relays like the relays in the marker Sarah showed us. The announcement set used a pretty standard tape head dragged along a soup can shaped magnetic drum by a lead screw, making a helical recording track. What was neat was if the user hung up on the intercept recording, the machine could reset almost instantly because a solenoid lifted the recording head and it sprung back to the start. An index leaf switch allowed the ringing to continue until the drum came around in rotation to the start of the recording. It was a really neat Rube Goldberg piece of equipment, but clever and reliable. The unit was supplied with a dedicated 500 style key telephone with the buttons controlling making the recording or setting it for playback. The one bad thing was that the drum rotation was very slow so it could hold three minutes of audio. I machined a sleeve to put over the drive capstan and the fatter diameter cut recording time to about one minute, but audio was much, much clearer.
I love this stuff, I had zero idea that the phone system was this complicated. Back when I was a teenager if I'd visited the local exchange on an open day then I WOULD have gone into phone work. However, home computers had just exploded onto the scene so I went that way instead. Many 'what ifs' though. Cheers Sarah!
Hello from the UK! Interestingly it seems that BT still use a whistle/howing tone for off hook. I found this out because my grandfather had dementia and left his phone off hook a couple of times. I had to find out “what the whistle was” in his home a few times.
When I was a kid we got our first cordless phone. I figured out if you pressed the hang up switch on the base and powered on the handset at the same time it would turn on and pick up random signals. I walked around my neighborhood and picked up other peoples calls. I caught some woman talking about her abortion.
Someone so young who really knows about the electrics of the telephone system. You have a wonderful array of central office equipment. Do you have tours?
In my childhood home with kids, cats and dogs, a phone getting knocked off-hook was fairly common. One sound that I remember in addition to the others was a siren-like sound that varied pitch, not loudness. It was quite effective!
Please keep doing these informative / historical videos. Really enjoy the insights on why things came to be, and how it was handled in different systems trough time.
In Sweden for a long time, until the beginning of the 90s, if both parties did not hang up the circuit would stay connected, so people could hang up and ask someone to pick up another phone in the home, but if the other party failed to hang up properly that also meant you could no longer make another call...
@@VarionJimmy Yeah, I think they started the digitalization in the 70s or 80s, but kept the behaviour for the users sake, or to be compatible with the few exchanges that were still mechanical.
@@frozendude707 Yes, this “bug” was utilised all the time. Not least in small business without a pbx (horribly expensive, one ‘state’ provider…). In our family shop, they had a separate old calling system, I recall how the secretary pushed several buttons to shout at my dad to pick up a phone - wherever he was… 😂 //Norrbagge-granne… 👍
That was how some telephone "bugs" worked. Either the telephone itself was modified so that hanging up would not cut off the microphone, or a separate microphone would be added to the circuit, either internally to the telephone or externally on the telephone line. You could dial the number, claim that it was a wrong number, then wait for the called person to hang up but you could keep the line open so you could listen in on what was going on close to the telephone. There were other methods too, many of which would keep the telephone from ringing at all while still opening up a microphone so you could listen in.
That was true for me in the US back in the 80s, too. Some people would leave their phone off hook if they got a prank call, sometimes for hours, thus disabling the prankster's phone until the target decided to hang up again.
Not at all, each subscriber line is linked to a dedicated input, it detects the hang up and start to wait for the dialling, if it not occurs the circuit is just released. The only thing that may happen was (at least in France) the line may be tagged with "electrical fault". A dedicated automated test robot, a dedicated hardware sitting beside the incoming line, test all the line once a day. All the incoming lines have a matrix of relay that disconnect the line from the exchange and connect it to the test equipment. As the physical constitution of the line was known (copper size, length of each section) and a profile keep in memory, the robot test line insulation A-ground B-ground A-B, wild voltage (from main power line caused by accident or really dumb electrician) and even an echometric test. The report will say the kind of fault and even is location from central office. At the time, they don't wait for customer complain, they come fix it even if you didn't notice anything yet. So, it may lead to a fault ticket for loop detected, but only after a few days. Now if the line is faulty and your DSL is not stable, they just limit the speed in the hope you'll not complain (like a line that could work at 20 but lost synch 10 time a day, they reduce speed to 15 to improve stability without fixing it) In the digital era most of “central office” was no more than “line digitizer” with sort of “trunk” (Technically it was an E1 link 30 voice channel MIC +2 control channel) to the “real” switch. So off hook use a slot in the “trunk” but release it after 30 seconds.
@@lapub. Bell Systems never used to do that. If you couldn't get a usable signal, they changed cable pairs or performed noise mitigation on the existing one. The all had to be rated at 9600 baud in the beginning, then 64k. That was plenty good for most dial-ups
@@Telephonebill51you're talking about dial up. DSL is adaptive to line quality - it's basically designed to utilize whatever excess quality your line has, that isn't needed for voice service, and every line is unique in that way. They've run DSL over actual wet string before, and chain link fence.
OH WOW!!! When I was growing up in rural CT in the late 80's early 90's, my mom would take the phone off the hook when she was leaving and no one would be home as a burglary prevention step. I never knew it would create such havoc in the CO!!!
The #5 I grew up on in SWBT territory (316-241 in Dec 1987 when it was cut out for an Ericsson AXE-10) the text in a mans voice was "Help there is trouble on the line please hang up..." The first time I heard it when I was 6-7 years old it so scared me I hung up immediately.
Here in the Twin Cities (Minnesota -- Northwestern Bell, later USWest, later Qwest), it was a woman's voice saying "If you'd like to make a call, please hang up and try again. If you need help, hang up and then dial your operator." After about 20-30 seconds off-hook, you'd get an answer-like click, then her message twice. Then a few more clicks and the off-hook beeping. Local alt-rock band The Replacements sampled it in parts of their song "Answering Machine" -- first at about 1:33 in, then repeated and distorted several times in the outro. ("If yOu'd liike tO mAke a caLL, plEase hAng up aNd trY agAin. If you nEEEd help... if you nEEEd help... if you nEEEd help..." "If yOu'd liike tO mAke a caLL...") *EDIT:* There were other messages with the same woman's voice for incomplete dials ("We're sorry -- your call did not go through. Please hang up, and..."), disconnected numbers ("The number **eight** **six** **seven** **...** **five** **three** **oh** **nine** **...** has been disconnected. No further information is available about this number."), not-in-service numbers, etc.
This channel repeatedly takes me back to the late 70s when I commissioned crossbar exchanges across the UK. If a subscriber went off hook and seized a register then did not dial, after a number of seconds an amber PG alarm bulb would light at the end of the rack. There was a maintenance routine where someone would manually release the circuit. #goodolddays
Back in the '70s, the exchange in Middletown Ohio would.t disconnect until the caller hung up. Someone hated a local cab company s they would call them, and lay down the handset. They would have to use another phone to get a tech to break the circuit . This required tracing the number the had way, so they would hang up about a minute before a trace could be completed. They would often make the call with a stolen butt set at a home's network interface.. Other nearby COs didn't have that problem. The Middletown CO was so old that they would salvage obsolete system of that design for spare parts. Middletown is a steel town so the CO was a very early design. Armco had a full 10K block of numbers reserved, Switching to a first generation ESS solved that and many other problems.
The UK phone system continued to operate like this until quite recently, long after there was any technical reason why the person being called couldn't end the call. I think BT eventually stopped doing this because scammers were abusing it to trick people into thinking they were calling their bank or whoever when they were actually still on the phone to the scammer.
@@makomk From what I've heard ove rthe yeas, BT is more about politics than technology. I spent many years on the old Electronics newsgroups and they always seemed to chose the worst way to do things. That function is just a configuration setting on an ESS, but they were so fixated on backwards comparability that changes were unthinkable.
@@georgecooke9010The name sounds familiar. I arrived around '54, and moved south in '87. I did electronic repairs, at Hall's TV in the '60, Dietz Electronics in the '70s, them my commercial sound and computer repair business. Did you know that Donald Trumps running mate is from Middletown? Even stranger was I picked up a science fiction book that started out , "Middletown, Hamilton and Fairfield were all destroyed..."
Oh hey and totally random thanks for the elevator knowledge. Got to run around with the elevator key trying to fix some thing. Door opening issues. I guess I should say I just got hired like two weeks ago as day-to-day building maintenance and related tasks. first day I was showed all the keys how fun! Second week they found out I like puzzles and I said doesn't really matter which key as I have a master key no not that kind the other kind. I also managed to fix a lock that the key was sticking in it. I sent a message to the guy that I am temporary replacing/dividing work and he was like yeah there's a trick to it it's always done that. When I pulled it apart it appeared that one of the springs got stuck between the plug and the body. I MacGyver the spring back to a spring, cleaned and re-lubricated it and really need to order some Springs but it doesn't stick anymore.
Fifty something years ago I was a trainee technician back in the Strowger/Step-by-Step days in NZ, and one of my duties was checking for PG alarms and applying the Howler. From what I remember, this was done at the equipment frames, there were jack sockets on the frames with access to the Howler tone (which was the incrementing continuous tone) and we plugged into the subscribers line directly at the final selector
I was training to work as a telephone "techie" for a while, and while it didn't work out, I still remember a lot. Here's an alternative (and less detailed) explanation just in case anyone needs it: When you picked up the receiver, the telephone exchange equipment would try to find a free connection for you to make a call with. That equipment would then be "locked in" to just your telephone. The equipment would be released by you hanging up the telephone. To avoid you tying up the equipment endlessly without dialling, a method was devised to time how long you had your telephone off-hook without dialling a number. When the time ran out, the equipment would be released and your telephone would be connected to a tone which was designed to catch your attention and persuade you to properly hang-up your telephone. On this side of the world, the tone was almost like a two-tone siren; a "wheeee-whooo" kind of noise. Hanging up would reset the equipment and (of course) disconnect the tone.
Your channel has never come across my feed before; the title of the video caught my attention instantly, and I subscribed as soon as you started explaining things - you're exactly my kind of content!
Growing up in NY in the 1960s we had a rented wall phone in the kitchen with a 25 foot handset cord. This was before modular cords so every time the cord stopped working from us twisting it around and stretching it all over the first floor of our house my mom would dial 0 and the phone company would send a repairman (never a woman) to install a new cord. Since we rented the phones there was no charge. We could finally buy our own phones in 1983 but many people continued renting them.
In the late sixties, my uncle would occasionally bring me along on trouble calls, especially if it was a quiet time on a weekend. He was a tech for a rural telecom back then. It was these visits that launched my fascination with electronics, math, science and geekdom in general. I remember one such trip to a smaller, older branch office where he showed me how he could troubleshoot the off-hook problems in much the same way as you demonstrated in this video. The “graduated howler” could go quite loud! If I remember correctly it was tube oscillator / amplifier circuitry then, but not sure. Keep up these great videos. Awesome.
Seems like a waste of a trouble card to print one at the start of an off-hook occurrence instead of at the end. Why not wait until the off-hook announcement then howler times out? Also, I realize the wiring of modern phones may prevent this, but why wasn't the option of sending ring voltage down the line during off-hook to alert the subscriber an option? That would be a lot louder than anything sent down to the handset.
In older phones, the ringer was simply paralleled with the line on a single party subscriber loop. The ringer was permanently capacitively coupled with approximately 2 mfd capacitor and the inductance of the ringer was sufficient to make it appear as an open circuit at speech frequencies … so ringing an off-hook subscriber set was theoretically possible … but the resistance of the carbon microphone and induction coil was on the order of just a few hundred Ohms, which is much lower than the impedance of the ringer. It gets more complicated on party lines because you have three ways of connecting the ringer: bridged, L1 to ground and L2 to ground. You can also have a bias spring on the ringer so that it will stay silent unless either a positive or negative DC bias is superimposed on the ringing. That lets at least six parties share one pair and still be signaled individually. You can also add ring cadence to the mix and train the subscriber not to pick up unless he hears his cadence. Even further, frequency selective components can be installed in the subscriber set and different ring frequencies used. If you ever watch a technically correct old movie, you’ll notice the person making a call picks up to listen for anyone on the line, then hangs up while cranking the magneto, then picks up again to listen for the operator. Same reason - the carbon transmitter needs to be out of the circuit or it will basically short out the magneto
Most phones that would be in a house discontinued the ringer when the handset was off hook, so if you sent ringing voltage down the line, you would not ring the ringer. You would just hear the AC voltage in the receiver, but the howler was louder and more annoying.
@@wtmayhew Party line was never a thing in my country, we just didn't have phone ! Fun fact they aired again "Alf" from 1986 where a child rant to get his own landline, not even able to share one with the house inhabitant. Nowadays no one have to ask to call to someone on a phone, neither have to tell who you are.
Back when we had POTS, if we didn't want to be bothered by phone calls, we'd dial our own # and leave off hook. It would just busy signal for quite awhile, then time out and just go silent. I never thought about what that does @ the exchange station. This was circa 80's-90's.
After an earthquake, a lot of phones would've gone off-hook because the receivers fell off the hook by the shaking or the phone itself fell down. Thus, one of the first things technicians did was to visit every payphone and start hanging them up so they'd clear the switch. Not so much these days, of course as it doesn't take any switch resources, but in the past to help lower the load and to get the switches operational again. Of course, those were the days where if you got enough people to take their phones off the hook at the same time, you could seize up the switch.
This was a great episode. I remember hearing that tone when I didn’t get the phone hung up. We’re planning another trip to the museum in September, I hope you can show this to us in person.
Love the video,as we always do. Please keep making them and don't change a thing. Congrats and thanks for getting the howler working on your panel switch.
Hey Sarah! As a European, I find this video super educational! Many thanks for sharing all this knowledge! :) Very fascinating! I have little knowledge of the phone systems, but I did serve in a SIG battalion during my military service, though that is a completely different barrel of fish. (some might be easier to shoot than others.)
I used to work in the UK on the old Strowger exchanges. We had a similar Howler setup, for the PG lines. Our fault dockets were about 10 times smaller, and were printed on pink paper. The night operator staff had loads of time on their hands, and would run the Lamp Test function on all our 80 operator positions, and present us with a couple of hundred Pink Dockets every Monday morning. . . Kept us busy for a few days, replacing bulbs and frayed cords.
Love this channel. I find the electromechanical aspect of telecommunications so fascinating and these machines are art to me. It's great younger generations can come on in and experience old school landlines not VOIP
Sarah, You are just cool. I've wanted to know about this stuff since I was a little boy in the 1960's. Somehow, I "found" a couple of phones that fell off of the dark green Mountain Bell Ford Econoline van that looked like the attached pic. My "plan" as a 6 year old in 1967 was to make a telephone network between my best friends house, three doors away, and me. I actually wired them up, with a battery and a bunce of old extention cables using the red and green wires. We could talk on those phones if we both were "off-hook," but I couldn't figure out how to make then ring. I KNEW that it had to be something to do with the yellow wire, but never figured out the formula. Till now..I've learned so much from this series. Please keep it up. Kelly Parker
Great presenter, having had a fascination in my early years with phone systems, worked on some office PBX stuff and all over the telecom and networking industry love to see these videos and explaining things showing how it all works.
When I worked a SxS switch in the mid 70's, lightning had hit a major cable fusing at least 1200 pairs together, which locked out other people from getting dial tone by tying up all the line finders/line groups. A fun day indeed. Thank you for this video, it brings back good memories when things were relatively simple.
Even in the 80s and early 90s, in a large city on the East Coast, I could still hear a lot of cross talk, messages from other off-hook lines, ringing sounds, touch tones, and other things, while making connections and the other end was ringing, or when leaving the line off hook past the subscriber alert tone. The crosstalk was never loud enough to understand, but sometimes somebody would yell loudly, and you could hear that the distorted high volume voice. The telco pre-recorded messages playing in the background over top of each other, and those three tones that always played before them, were much more recognizable.
I don't know how this ended up in my feed, but it's really interesting! Thanks! Fun fact: On a rotary dial phone, if you wanted to take the phone off the hook for a while and not hear the annoying tone, after removing the handset you could move the dial a couple places and stick a pencil into a finger hole to prevent it from returning.
I definitely learned something. In the 70s and 80s we would get a high pitched steady tone if you left your phone off hook. The exchange that ran our phones was a C2 exchange. I had no idea that this would create work for someone at the telephone company. I always assumed it was like a busy signal. The call simply terminated with a tone. It’s interesting to learn that this activity was being monitored. Thanks for the video. Very interesting.
The village I live in got a WE panel office installed in 1965. It was a 4 digit office (2xxx, 5xxx, and 9xxx for payphones) built as a satellite off of a crossbar in the next village. We could only dial 4 digits within our exchange, 7 digits to our immediate neighbors and 1+7 digits to the rest of our area code. Our office had between 7 and 11 senders with no timeout. There were times when off-hook did not give a dial tone.
When I was a kid and I left the phone off the hook for fun hehe , first would come the howler tone then "Please hang up and try your call again, if you need assistance, dial your operator PLEASE HANG UP *NOW*, this is a recording" i had nightmares because it was a very forceful NOW!
I too remember that voice recording for long off hook. It was a male voice, and he sounded kinda mad, like he was gonna visit you personally. "Please hang up and try your call *again*. If you need help dial the operator. Please hang up NOW!" I think your memory of the exact words is actually the correct one.
In the early 2000's heard that tone after a lightning strike in my apartment in LA, IDK how it fried the phone to go off hook, woke up to that loud noise and I think an announcement telling me to hang up late at night, had to disconnect it from the plug to silence it. It was an electric cordless speaker phone with an answering machine, never worked after that night. The lightning strike also took out the stove/oven LED panel since it was not grounded (old outlet)
Ah, that tone off-hook sound you played in the start of the video is the same one that Virgin Media in the UK uses, which is apparently different to the one BT used. Funny that it was that tone specifically copied from the US here.
Seems from the user's point of view, permanent signal on the #5XB and the #5ESS is pretty much the same, except the #5ESS will ring once or twice before the announcement. When I was growing up, I had (and still have) a landline served by a #5ESS. I remember I was absolutely terrified by the ROH tone, I would just hide under a bunch of blankets until it went away, and then hang up the phone :) Edit: interesting side note, after the ROH tone ends, usually this particular #5ESS (or line card) makes a loud, brief "Bzzzrt" sound just after the ROH tone ends, I don't know if they all do that.
You always have such interesting topics. There is so much I didn’t know about the actual operation of a central office. I would say the #5 cross bar was probably the most complicated electromechanical switch ever built. Pretty soon though you are going to have to explain to the younger generation what a “dial tone” is!
Great video I've always wondered what the effect was of leaving a phone off the hook on the other end! Has the timeout for dropping a trouble card been adjusted for the museum though? In an active office, it seems like it would be using up a lot of cards (and engineer time) if it dropped a card every time someone leaves their phone off hook for 30 seconds.
I seem to recall back in the 90s.. when i'd have to leave the phone off the hook for some reason (usually people calling that were bugging us).. it'd do the off hook tone for a while, then it then a few clicks in the background, then a really LOUD howling sound (not the one you played around 8 minutes in), but really howling sounding. Really annoying, but at the time, we had to do it.
I'm wondering if there's anything in that script that covers Emergency situations, like someone tries to call for help but for whatever reason is unable to dial.
I can see how modern advancements would fix that due to the amount of people who didn't care or notice or whatever the phone was off hook. Did the later I know from my childhood if you left it off hook long enough. It would just go dead. But, you would still have to monitor something since once you hang up the phone. That reset the system.
I wonder how many trouble tickets I generated as a kid. I know how many trouble tickets I generated for my parents, I could add them to the pile and get a final score for growing up.
When I was a kid in South Africa in the 1970s, if one side didn't hang up the phone, the connection stayed up. That meant that even the side that *did* hang up the phone could not make or receive calls. If you found yourself in this situation, you had to pick up the phone and yell or whistle in the hopes that the person who forgot to hang up would realize it.
I can recall 2 distinct things from movies & TV that dealt with this exact thing...There was a revival of Perry Mason in the 70s and in one episode there was a murder almost caught on one of those newfangled video cameras (the pre-VCR kind, camera knocked out of position so there was only audio) in which one could hear the modern off-hook tone, and it was explained that the phone company had recently switched to that type of tone...leading to the theory that someone called the phone to get the secretary out of the office to go look for the call recipient but the caller just hung up, leaving the office phone off-hook, allowing the murder to occur...Earlier around 1965 there was a film called I Saw What You Did with Joan Crawford, where 2 teen girls babysitting are making prank calls, and one just happens to be to a guy about to kill his wife who suspects the prank caller is his mistress...after he kills his wife and buries her in the yard he returns to the phone, long hung up by the girls, and the off-hook tone is the older 'mosquito' or siren tone, rising & falling in pitch repeatedly. Not sure when that replaced high tone but I remember hearing a short bit of high tone in the 70s just before Jane Barbe would come on...the first time I heard it I was a kid and finally got a dialtone after an outage and was holding the line to see if my parents needed to make a call - then suddenly high tone came on, then the voice recording and finally the intermittent howler - scared the living crap out of me and even tonight watching this video at age 60, I still get the goosebumps a bit at that sound. It is used to great dramatic effect by composer Steve Reich in his composition for the Kronos Quartet, "WTC 9/11"...very poignant and somewhat disturbing but a great piece of music.
I was always under the impression that the tone was applied continually until hangup. I should note I'm younger so have probably only been on electronic switches. I learned the hard way recently that the ATA in our fiber ONT only plays the howler for a few seconds so I had no idea my phone was knocked off hook.
Neat! I can't remember which phone but I remember growing up one of the phones we had in the house if you put it down a fraction of an inch too far "down" towards the bottom of the base it would not fully press the hook switch so you believed the phone was hung up but it was actually off hook. We'd randomly have where you went to make a call and pick up a phone and either had the beeping tone or a dead line and then have to begin troubleshooting "ok who left something not hung up or what happened". Never know how that worked.
"PLEASE HANG UP AND TRY YOUR CALL AGAIN! PLEASE HANG UP, THIS IS A RECORDING!" I used to get old people who would take the phone off hook and then think about the number they wanted to dial. Then they would pick up the handset and with a shocked look hand it to me and say "Someone is talking on the phone!" So I had to tell them to make up their mind before they remove the phone from the cradle because they were tanking too long. Fast forward a few years in my telecom career. I get an old lady who has the same issue. So I tell her tocall a number so I can observe what I am sure is her taking too long. Well, she picked up the handset and hit the pushbuttons so fast the DMS couldn't determine the gaps between button pressing. So I asked her what she did before she retired and she said "data entry." So I had to tell her to slow down...Totally unexpected.
On the small AE SxS exchanges I worked on the in the Army, a permanent off-hook would just hang the first selector and cause a PRS alarm on the frame. We'd have to go through the first selectors to look at the wipers to fins out which line it was. Once we found the offending line we'd put a shoe on the frame from the test desk on the pair looking out to see if it was off-hook, short or water. If it was off hook we'd patch it to a really loud Lorain howler that was much more annoying than the Western howler, if that didn't work, we'd leave the shoe in it and if we needed the shoe for something else, we'd pick out the pair and wait for the sub to complain.
Another problem is when during a say snow storm, everyone wants to call someone. All of the available lines are being used and when you lift the receiver and get no dialtone. All you hear is a side tone, people talking and nothing else.
Heard, back around 1970 or so, in New York City, people would take their phones off hook to make it seem that they are on the phone talking to someone, so burgles dialing their number from a pay phone would hear a busy signal, thus making him think someone is home. Some neighborhoods had a lot of this, and sometimes the office equipment would burn out from overload.
I upgraded my landline to a virtual PBX option last year when i changed my service provider. The little box they give you to connect your old landline phone mimics these features very well. But i do think the warning beep is a bit too quiet lol
Around the 90's I remember a person would also get on the other side to get your attention after all the beeping to tell you to hang up the phone. Around the 2000's it would be a recorded voice. Nowdays it's just the beeping or a loud af tone which I think it destroys your phone in the process. 💀
Im not sure of the 1990s technology with phone systems but can you please talk about dial up internet. and how it tied together with the phone technology at the time!
Back in 1973 our hospital had a rotary dial system run by a soon to retire telephone repair man and our company had installed a paging system that would work off that old system I get to see the antique system ....very noisy
I remember the howler. Sadly it is no more on Bell Aliant in Atlantic Canada. I used to have copper landline which was asome our phones always worked even if our power was out for days because of hurricane damage, however when we got fibre to the home for fast internet they switched our land line over to the fibre to the home hub in our basement so now our land line is IP based back to the CO. I now have to have a UPS(battery backup) to keep our land line running. It sucks. Lol there is no howler either if you leave the phone off hook. Just a fast busy signal after 20 seconds. Boring
I remember when I was much younger and living with my parents, we could hear this quiet high pitch whistling noise and we were all hunting around for what was causing it. Turned out to be the phone in the living room hadn't quite seated back properly when it was put on hook, so we'd been given the howler treatment 😅😅. This would have been late 70s, early 80s UK.
In digital switches the DTMF receivers are provisioned packs, but the difference is that the switch will eventually time out a line and release the DTMF receiver. You can run out of DTMF receivers if call volume goes high enough.
Merp! I really enjoyed this :3 Also, as a vintage computer nut, we definitely have something amazing to obsess over: the 5ESS switch! As you probably already know, it was based off of AT&T's 3B computer systems. Which I'm fortunate enough to own, albeit the desktop 3B2!
I wish that this video had gone into further depth. How were the 30-40 second timers managed? A mechanical timer at each sender? A slowly charging capacitor? How were the special tones and "please hang up" voice unit done? I will definitely have a field day when I eventually visit your museum learning about all of the stuff that I was so curious about when I was a teenager.
Man just imagine how many trouble tickets and work was created for the phone company employees just because someone took the phone the hook just so they didn’t want to be disturbed
The more I learn about the old telephone system, the more wild it becomes. The sheer complexity of it all. It’s incredible it ever worked in the first place.
@@mutestingray
Haha, yep. All done with electromagnets, springs and pieces of metal.
And with the correct maintenance they’d reliably do millions of cycles.
So far as the (UK style) Strowger equipment went there were only three generations. Up to 1936, 1936-1956, then 1956 onwards (dates are approximate)
A cut cable didn't always cause lines to be shorted, BUT, if a cable got water into it, that would definitely cause a mass short. a 5ESS would protect itself by turning the battery off to those lines fairly quickly, but a old EM switch would just keep pumping battery into the wet short until it turned into a green gooey mess from electrolysis, especially if it was a splice that got wet. If caught in time, a ticket was ordered for a CO tech to remove the heat coils in the range of pairs that was affected by that wet cable, until it was attended to by a crew ( which as a cable splicer I was tasked to do for larger cable outages)
No air pressure?
@@Telephonebill51 HA! Depending on, a LOT of variables, air pressure may be a blessing, or a curse. Most times it may keep water out of a small leak in an underground cable, but, it could also cause a poorly wrapped temporary closure ( not used a lot since the 1980's, because not many could put them on properly anymore) to blow out, causing a MUCH larger leak that may also cause a splice to become wet quickly if water came up in a manhole run due to a flooding rain. And then, a flooding rain has caught more than one tech ( not me, thankfully) off guard and unable to close a splice they were working in before water got into it.
5ESS would cut battery after a couple of howler iterations. But it would restore fairly quickly too if you hung the phone back up.
I had a friend at Mich Bell who was in charge of an older office in a neighborhood with a lot of pulp cables. When it rained hard he had to hurry into the office to pull the coils in the known worst cables or the switch would go down.
Oh I didn't think of that. If a modern data wire gets wet, Ethernet or whatever, it wouldn't do that because there's no battery. And of course fiber optics are basically waterproof although.
Another reason for phones going off hook, especially in the Seattle area, is earthquakes. The shaking will knock phones every which way including pay phones (yes I'm that old to remember what a pay phone is). The guides for post disaster actions ask if you find a phone off hook hang it up. This helps clear the the jam faster allowing service to come back faster.
Reading this comment thinking that would be a good uncle Sam poster. you know the one with the finger pointing at you to join the army or in this case put the phone back on the hook.
Why would a payphone off the hook matter?
@@robertgift There isn't enough call processors to handle all of the phones. Every phone off hook is asking for a call processor. At the time I saw that message payphones would operate without coins. so you could dial emergency services.
An interesting, seemingly meaningless action until you know how things work.
Talking about pay phones, reminds me that here in Brazil, phones were a weird deal way into the mid to late 90s. It costed a heck lot to have a landline, not even talking about mobile networks, and thus very few people had them at all. Like, I mean it costed about the price of a cheaper brand new car to install the line. To solve the communication issue, people would often learn about the closest pay phone number and call THAT thing instead, so that someone on the neighborhood would pick it up and pass the call to who it's intended to.
It's funny to think of a public pay phone ringing out of nowhere, but they are indeed phones like all others and people here used them as such. Back when I was a kid I had a pay phone card with me all the time in case I needed to call home (by that point, phones were already common but not common for kids in the early 2000s to have had cell phones).
@@randycarter2001 - My dad was a telephone man, and when we had to make an emergency call on a camping trip without a coin, my dad took a sharp pin and put it in the carbon mic and touched it to the body of the payphone and up came the dial tone. He was able to get the operator to place a call for us. Those old pay phone circuits were Ground Start. Those were the days when the pay phones had three holes 5¢ 10¢ and 25¢ and generated a single tone for each coin. :) Unlike later systems that generated two 66ms pulses of 1700/2200 for dimes, one 66ms pulse for nickles, & for the quarters five 33ms pulses with 33ms rests of that same 1700/2200 mix. Anyone for RedBox my good man? LOL
I think it would be pretty cool to see the scripts used when talking to subscribers
Second this. Was really hoping for a script read.
@@t0b0Ditto
Yes! When Sara mentioned the scripts, I was hoping that she'd read off them, or show them to us. :)
Back in the 80s, there’d be times I’d be visiting my grandmother and she was still leasing an old rotary phone from the phone company. Sometimes the handset wouldn’t sit back properly and eventually the beeping would come on. Once I went to put the handset back down but the beeping stopped. I assumed it fixed itself but then I heard talking. The operator came on asking if anyone was there. I then hung up. We were in Southern California served by Pacific Bell at the time. After she passed, my dad tried to return the leased phone back to SBC and they didn’t know what to do because they stopped leasing phones a long time ago.
Even though I was born in the 60s, I always learn something new on your channel. Please continue!
In France they never stop the leasing even if they stop maintaining theses phones years ago (like 1995) there is a bunch of grandma still paying for theses and when it broke they just tell, we don't lease phone anymore, you must buy a new one.
They even rise the fee from 1€50 to 2€ /month. They even still send fee to some people that close the line, but they still send the bill for lease.
@@swsuwave Hi, I’m flattered if you meant that comment for me. However, I believe you replied to my comment when that was meant for Sarah.
@@FinnleysAudioAdventures Must be the grey hair here! Sorry bout that, but yes it was meant for Sarah. Guess that shows I don't know how to send a comment to a presenter - hopefully she gets this!
@@swsuwave probably just ended up in the wrong comment box.
"If you'd like to make a call, please hang up and try again. If you need help, hang up, and then dial your operator."
… In Albuquerque
"Sarah waiting for machines on camera" is very wholesome content, and probably a genre in itself.
A super-cut. Love it!
What happens if you leave your phone off the hook? Well...from first hand experience I can say that the first three days are absolute bliss and unimaginably peaceful. Then, after about four days, your girlfriend gets worried that she always gets a busy signal so she automatically assumes the mob came and attacked you leaving you lying on the floor in your basement (because that just makes perfect sense). Next your she has her stepfather drive two hours each way (she doesn't have the time to take the bus herself) to knock on your door and ask if your ok. When he points out that everyone gets a busy signal you go and look at the phone and realize that it had been pushed under the couch and the cat had knocked it off the cradle.
Off topic but when I was a phone phreaker in the 70's, we had numbers that were like permanent busy signals where you could talk loud and hear and talk to others. Of course the loop lines were more fun!
When my Mom had a landline she would take it off hook every time she went to take a shower, so that she wouldn't feel pressured to jump out and answer the phone if it rang. I never considered the possibility of a CO worker taking action on that.
Me either. As a kid, I would definitely have experimented with taking a phone off-hook just to study what happened. Sorry, CO workers!
Same and the number of movies that portray if you don't wanna be bothered just take it off the hook.
@@nickwallette6201 As kids we learned not to mess with the operator or 611. They knew where you lived. Everyone else you could swear at with impunity! Just to be safe we left the police alone too. And radio / TV stations, they had tape recorders.
And eventually maybe the CO guys figured it out that Mrs Grable was taking a shower. 😂
I was taught long ago if I wanted to prevent the phone from ringing to dial my number. I’d hear busy signal and now I know that a sender was released for someone else to use.
& there's a trouble card out there for every time mother took a shower...
Anecdote; As a 70’s kid in Norway, I’m pretty sure we didn’t have the “holler” step in the fault sequence. The older generation electro-mechanical switch (small town, possibly Strowger from early 30’s?) would cut the dial tone, then go silent (line noise, ghost audio). Not much happening at the subscriber end, as I recall.
Our local office was digitised quite early (just prior to 1980?), and this equipment simply switched to a busy-signal, maybe with a slightly different timing.
Hard to know what people used to do, but the phone book (part that nobody read, except nerdy me) asked people to pull the plug - please don’t off-hook.
Thanks for another great video! 😊
As a 70’s kid in Sweden I have the same memories. 😊
//Fra en annen natteravn.
@@VarionJimmy Me too (Sweden), Leaving the phone off-hook was the easy way to not get disturbed. Much easier than running around and pulling the plugs of all four phones in the house!
Imagine all the trouble cards and alarm bells we would have caused if it were in the US!
@@mumiemonstretExactly! 😊
When I was a kid, our town was served by a Bell SxS office. I believe the permanent signal tone was a wailing noise which varied in pitch which customer’s called the crybaby. The SxS office was interesting because there were enough microphonics, crosstalk or whatever going on, that you could usually hear pulsing, relay clicks and various noises. The background noise was more noticeable before the called party was cut in, but it was still audible in conversations. Crossed speech was unusual, but sometimes indistinctly audible. The town cut over to ESS in July of 1976, and it was a bit disconcerting because all that background noise disappeared all at once
The first time I heard the "crybaby" tone, I was falling asleep to one of Evan Doorbell's recordings. It made me about jump out of bed, it was so startling. I'm sorry I missed the days of interesting tones and background noises on landlines, but I'm not sad to have missed that one.
@@jonathankleinow2073 Thanks for the reply. Yes it got your attention, like a mini air raid siren.
I remember you still heard a lot of crosstalk and random noises when the recordings came on though, like the "if you'd like to make a call, please hang up and try again..." message. I wonder why that was.
@@viktorakhmedov3442 Changing the topic slightly, I had an AT&T announcement set back in the 1980s. It was heavy - like 20 pounds. The thing was full of germanium transistors and relays like the relays in the marker Sarah showed us. The announcement set used a pretty standard tape head dragged along a soup can shaped magnetic drum by a lead screw, making a helical recording track. What was neat was if the user hung up on the intercept recording, the machine could reset almost instantly because a solenoid lifted the recording head and it sprung back to the start. An index leaf switch allowed the ringing to continue until the drum came around in rotation to the start of the recording. It was a really neat Rube Goldberg piece of equipment, but clever and reliable. The unit was supplied with a dedicated 500 style key telephone with the buttons controlling making the recording or setting it for playback.
The one bad thing was that the drum rotation was very slow so it could hold three minutes of audio. I machined a sleeve to put over the drive capstan and the fatter diameter cut recording time to about one minute, but audio was much, much clearer.
Damn, steps got cut to DMS 100's and ESS's decades ago.
I love this stuff, I had zero idea that the phone system was this complicated. Back when I was a teenager if I'd visited the local exchange on an open day then I WOULD have gone into phone work. However, home computers had just exploded onto the scene so I went that way instead. Many 'what ifs' though. Cheers Sarah!
Hello from the UK!
Interestingly it seems that BT still use a whistle/howing tone for off hook. I found this out because my grandfather had dementia and left his phone off hook a couple of times. I had to find out “what the whistle was” in his home a few times.
When I was a kid we got our first cordless phone. I figured out if you pressed the hang up switch on the base and powered on the handset at the same time it would turn on and pick up random signals. I walked around my neighborhood and picked up other peoples calls. I caught some woman talking about her abortion.
"When you pick up your telephone, you are assigned a sender *mechanical noises in the background.*"
That's actually an excellent demonstration
Someone so young who really knows about the electrics of the telephone system. You have a wonderful array of central office equipment. Do you have tours?
In my childhood home with kids, cats and dogs, a phone getting knocked off-hook was fairly common. One sound that I remember in addition to the others was a siren-like sound that varied pitch, not loudness. It was quite effective!
Here in Australia it was called a Howler, to get the attention of the subsciber.
Please keep doing these informative / historical videos. Really enjoy the insights on why things came to be, and how it was handled in different systems trough time.
The "I don't Care Anymore" Plug :)
Interesting circuit, I learned something new today. Thanks!
"Mew."
In Sweden for a long time, until the beginning of the 90s, if both parties did not hang up the circuit would stay connected, so people could hang up and ask someone to pick up another phone in the home, but if the other party failed to hang up properly that also meant you could no longer make another call...
That was really useful some times.
//Another Swede.
@@VarionJimmy Yeah, I think they started the digitalization in the 70s or 80s, but kept the behaviour for the users sake, or to be compatible with the few exchanges that were still mechanical.
@@frozendude707 Yes, this “bug” was utilised all the time. Not least in small business without a pbx (horribly expensive, one ‘state’ provider…). In our family shop, they had a separate old calling system, I recall how the secretary pushed several buttons to shout at my dad to pick up a phone - wherever he was… 😂
//Norrbagge-granne… 👍
That was how some telephone "bugs" worked. Either the telephone itself was modified so that hanging up would not cut off the microphone, or a separate microphone would be added to the circuit, either internally to the telephone or externally on the telephone line. You could dial the number, claim that it was a wrong number, then wait for the called person to hang up but you could keep the line open so you could listen in on what was going on close to the telephone.
There were other methods too, many of which would keep the telephone from ringing at all while still opening up a microphone so you could listen in.
That was true for me in the US back in the 80s, too. Some people would leave their phone off hook if they got a prank call, sometimes for hours, thus disabling the prankster's phone until the target decided to hang up again.
I see you have 28.8k subscribers now. Next stop, 56k!
I guess you could stop at 33.6k first, but I would go all the way up to Ludicrous Speed v.92 56k
@@MichaelCowden lol, I came here to say you forgot 33.6. But I guess you didn’t.
It's "bad" for digital switches, too. They have a finite number of DTMF decoders.
Not at all, each subscriber line is linked to a dedicated input, it detects the hang up and start to wait for the dialling, if it not occurs the circuit is just released. The only thing that may happen was (at least in France) the line may be tagged with "electrical fault". A dedicated automated test robot, a dedicated hardware sitting beside the incoming line, test all the line once a day. All the incoming lines have a matrix of relay that disconnect the line from the exchange and connect it to the test equipment. As the physical constitution of the line was known (copper size, length of each section) and a profile keep in memory, the robot test line insulation A-ground B-ground A-B, wild voltage (from main power line caused by accident or really dumb electrician) and even an echometric test.
The report will say the kind of fault and even is location from central office. At the time, they don't wait for customer complain, they come fix it even if you didn't notice anything yet. So, it may lead to a fault ticket for loop detected, but only after a few days.
Now if the line is faulty and your DSL is not stable, they just limit the speed in the hope you'll not complain (like a line that could work at 20 but lost synch 10 time a day, they reduce speed to 15 to improve stability without fixing it) In the digital era most of “central office” was no more than “line digitizer” with sort of “trunk” (Technically it was an E1 link 30 voice channel MIC +2 control channel) to the “real” switch. So off hook use a slot in the “trunk” but release it after 30 seconds.
@@lapub. Bell Systems never used to do that. If you couldn't get a usable signal, they changed cable pairs or performed noise mitigation on the existing one. The all had to be rated at 9600 baud in the beginning, then 64k. That was plenty good for most dial-ups
@@Telephonebill51you're talking about dial up. DSL is adaptive to line quality - it's basically designed to utilize whatever excess quality your line has, that isn't needed for voice service, and every line is unique in that way. They've run DSL over actual wet string before, and chain link fence.
I love the enthusiasm with your videos. Great teacher.
I agree, but also, great handle! "Mongo just pawn in game of life."
OH WOW!!! When I was growing up in rural CT in the late 80's early 90's, my mom would take the phone off the hook when she was leaving and no one would be home as a burglary prevention step. I never knew it would create such havoc in the CO!!!
The #5 I grew up on in SWBT territory (316-241 in Dec 1987 when it was cut out for an Ericsson AXE-10) the text in a mans voice was "Help there is trouble on the line please hang up..." The first time I heard it when I was 6-7 years old it so scared me I hung up immediately.
Here in the Twin Cities (Minnesota -- Northwestern Bell, later USWest, later Qwest), it was a woman's voice saying "If you'd like to make a call, please hang up and try again. If you need help, hang up and then dial your operator." After about 20-30 seconds off-hook, you'd get an answer-like click, then her message twice. Then a few more clicks and the off-hook beeping.
Local alt-rock band The Replacements sampled it in parts of their song "Answering Machine" -- first at about 1:33 in, then repeated and distorted several times in the outro. ("If yOu'd liike tO mAke a caLL, plEase hAng up aNd trY agAin. If you nEEEd help... if you nEEEd help... if you nEEEd help..." "If yOu'd liike tO mAke a caLL...")
*EDIT:* There were other messages with the same woman's voice for incomplete dials ("We're sorry -- your call did not go through. Please hang up, and..."), disconnected numbers ("The number **eight** **six** **seven** **...** **five** **three** **oh** **nine** **...** has been disconnected. No further information is available about this number."), not-in-service numbers, etc.
Social Workers Benevolent Trust? Just asking.
@@RWBHere South Western Bell Telephone
This channel repeatedly takes me back to the late 70s when I commissioned crossbar exchanges across the UK. If a subscriber went off hook and seized a register then did not dial, after a number of seconds an amber PG alarm bulb would light at the end of the rack. There was a maintenance routine where someone would manually release the circuit. #goodolddays
The beeping noise from the receiver off hook used to scare the crap out of me when I was a kid.
Back in the '70s, the exchange in Middletown Ohio would.t disconnect until the caller hung up. Someone hated a local cab company s they would call them, and lay down the handset. They would have to use another phone to get a tech to break the circuit . This required tracing the number the had way, so they would hang up about a minute before a trace could be completed. They would often make the call with a stolen butt set at a home's network interface.. Other nearby COs didn't have that problem. The Middletown CO was so old that they would salvage obsolete system of that design for spare parts. Middletown is a steel town so the CO was a very early design. Armco had a full 10K block of numbers reserved,
Switching to a first generation ESS solved that and many other problems.
The UK phone system continued to operate like this until quite recently, long after there was any technical reason why the person being called couldn't end the call. I think BT eventually stopped doing this because scammers were abusing it to trick people into thinking they were calling their bank or whoever when they were actually still on the phone to the scammer.
@@makomk From what I've heard ove rthe yeas, BT is more about politics than technology. I spent many years on the old Electronics newsgroups and they always seemed to chose the worst way to do things. That function is just a configuration setting on an ESS, but they were so fixated on backwards comparability that changes were unthinkable.
THAT AND LEAVE THE PHONE RING FOR AN HOUR OR SO IF THEY WOULDN'T PICK UP. MY FRIEND SUE SHOCKEY MOVED TO MIDDLETOWN IN THE 70S! 👍👍👍
@@georgecooke9010The name sounds familiar. I arrived around '54, and moved south in '87. I did electronic repairs, at Hall's TV in the '60, Dietz Electronics in the '70s, them my commercial sound and computer repair business.
Did you know that Donald Trumps running mate is from Middletown?
Even stranger was I picked up a science fiction book that started out , "Middletown, Hamilton and Fairfield were all destroyed..."
12:28 totally agree, that track is a bop 💃🕺🎵🎶😊
Oh hey and totally random thanks for the elevator knowledge. Got to run around with the elevator key trying to fix some thing. Door opening issues. I guess I should say I just got hired like two weeks ago as day-to-day building maintenance and related tasks. first day I was showed all the keys how fun! Second week they found out I like puzzles and I said doesn't really matter which key as I have a master key no not that kind the other kind. I also managed to fix a lock that the key was sticking in it. I sent a message to the guy that I am temporary replacing/dividing work and he was like yeah there's a trick to it it's always done that. When I pulled it apart it appeared that one of the springs got stuck between the plug and the body. I MacGyver the spring back to a spring, cleaned and re-lubricated it and really need to order some Springs but it doesn't stick anymore.
I know my mum would put the phone off hook to not be disturbed (NZ in the 90’s), our off hook timeout tone was just pulsed dial tone
Fifty something years ago I was a trainee technician back in the Strowger/Step-by-Step days in NZ, and one of my duties was checking for PG alarms and applying the Howler.
From what I remember, this was done at the equipment frames, there were jack sockets on the frames with access to the Howler tone (which was the incrementing continuous tone) and we plugged into the subscribers line directly at the final selector
I was training to work as a telephone "techie" for a while, and while it didn't work out, I still remember a lot. Here's an alternative (and less detailed) explanation just in case anyone needs it:
When you picked up the receiver, the telephone exchange equipment would try to find a free connection for you to make a call with. That equipment would then be "locked in" to just your telephone. The equipment would be released by you hanging up the telephone. To avoid you tying up the equipment endlessly without dialling, a method was devised to time how long you had your telephone off-hook without dialling a number. When the time ran out, the equipment would be released and your telephone would be connected to a tone which was designed to catch your attention and persuade you to properly hang-up your telephone.
On this side of the world, the tone was almost like a two-tone siren; a "wheeee-whooo" kind of noise. Hanging up would reset the equipment and (of course) disconnect the tone.
Your channel has never come across my feed before; the title of the video caught my attention instantly, and I subscribed as soon as you started explaining things - you're exactly my kind of content!
Man I love this channel. All this old tech I haven't seen from before my time. Thank you and everyone for all the hard work to preserve this Sarah!
Growing up in NY in the 1960s we had a rented wall phone in the kitchen with a 25 foot handset cord. This was before modular cords so every time the cord stopped working from us twisting it around and stretching it all over the first floor of our house my mom would dial 0 and the phone company would send a repairman (never a woman) to install a new cord. Since we rented the phones there was no charge. We could finally buy our own phones in 1983 but many people continued renting them.
I recall when the receiver was off hook, it would make a high/low whine like scalding cats to various levels of volume.
In the late sixties, my uncle would occasionally bring me along on trouble calls, especially if it was a quiet time on a weekend. He was a tech for a rural telecom back then. It was these visits that launched my fascination with electronics, math, science and geekdom in general. I remember one such trip to a smaller, older branch office where he showed me how he could troubleshoot the off-hook problems in much the same way as you demonstrated in this video. The “graduated howler” could go quite loud! If I remember correctly it was tube oscillator / amplifier circuitry then, but not sure. Keep up these great videos. Awesome.
Way back it could be an emergency in the UK the emergency services would eventually pop round
Seems like a waste of a trouble card to print one at the start of an off-hook occurrence instead of at the end.
Why not wait until the off-hook announcement then howler times out?
Also, I realize the wiring of modern phones may prevent this, but why wasn't the option of sending ring voltage down the line during off-hook to alert the subscriber an option? That would be a lot louder than anything sent down to the handset.
It's an option. You can flip a key to turn that on or off. I turned it on for the demo.
In older phones, the ringer was simply paralleled with the line on a single party subscriber loop. The ringer was permanently capacitively coupled with approximately 2 mfd capacitor and the inductance of the ringer was sufficient to make it appear as an open circuit at speech frequencies … so ringing an off-hook subscriber set was theoretically possible … but the resistance of the carbon microphone and induction coil was on the order of just a few hundred Ohms, which is much lower than the impedance of the ringer.
It gets more complicated on party lines because you have three ways of connecting the ringer: bridged, L1 to ground and L2 to ground. You can also have a bias spring on the ringer so that it will stay silent unless either a positive or negative DC bias is superimposed on the ringing. That lets at least six parties share one pair and still be signaled individually. You can also add ring cadence to the mix and train the subscriber not to pick up unless he hears his cadence. Even further, frequency selective components can be installed in the subscriber set and different ring frequencies used.
If you ever watch a technically correct old movie, you’ll notice the person making a call picks up to listen for anyone on the line, then hangs up while cranking the magneto, then picks up again to listen for the operator. Same reason - the carbon transmitter needs to be out of the circuit or it will basically short out the magneto
Most phones that would be in a house discontinued the ringer when the handset was off hook, so if you sent ringing voltage down the line, you would not ring the ringer. You would just hear the AC voltage in the receiver, but the howler was louder and more annoying.
@@wtmayhew Party line was never a thing in my country, we just didn't have phone !
Fun fact they aired again "Alf" from 1986 where a child rant to get his own landline, not even able to share one with the house inhabitant.
Nowadays no one have to ask to call to someone on a phone, neither have to tell who you are.
@@wtmayhew The capacitor was used to block DC pulses, like from the dial, from ringing the bell.
I wish I could use one of those not-my-problem plugs for a lot of subjects.
Back when we had POTS, if we didn't want to be bothered by phone calls, we'd dial our own # and leave off hook. It would just busy signal for quite awhile, then time out and just go silent. I never thought about what that does @ the exchange station. This was circa 80's-90's.
After an earthquake, a lot of phones would've gone off-hook because the receivers fell off the hook by the shaking or the phone itself fell down. Thus, one of the first things technicians did was to visit every payphone and start hanging them up so they'd clear the switch. Not so much these days, of course as it doesn't take any switch resources, but in the past to help lower the load and to get the switches operational again. Of course, those were the days where if you got enough people to take their phones off the hook at the same time, you could seize up the switch.
This was a great episode. I remember hearing that tone when I didn’t get the phone hung up.
We’re planning another trip to the museum in September, I hope you can show this to us in person.
Love the video,as we always do. Please keep making them and don't change a thing. Congrats and thanks for getting the howler working on your panel switch.
I once left the phone off the hook for 5 minutes just to see what happened. Sorry about that
Hey Sarah! As a European, I find this video super educational! Many thanks for sharing all this knowledge! :) Very fascinating! I have little knowledge of the phone systems, but I did serve in a SIG battalion during my military service, though that is a completely different barrel of fish. (some might be easier to shoot than others.)
I’m fascinated by failure modes and edge-cases. These videos are always good, but seeing this one really excited me.
Backhoe fade!
As a child in the 60s, the operator would make a phone inoperative if a child kept making fake calls or just was playing with the phone.
I used to work in the UK on the old Strowger exchanges. We had a similar Howler setup, for the PG lines. Our fault dockets were about 10 times smaller, and were printed on pink paper. The night operator staff had loads of time on their hands, and would run the Lamp Test function on all our 80 operator positions, and present us with a couple of hundred Pink Dockets every Monday morning. . . Kept us busy for a few days, replacing bulbs and frayed cords.
Love this channel. I find the electromechanical aspect of telecommunications so fascinating and these machines are art to me.
It's great younger generations can come on in and experience old school landlines not VOIP
Sarah, You are just cool. I've wanted to know about this stuff since I was a little boy in the 1960's. Somehow, I "found" a couple of phones that fell off of the dark green Mountain Bell Ford Econoline van that looked like the attached pic. My "plan" as a 6 year old in 1967 was to make a telephone network between my best friends house, three doors away, and me. I actually wired them up, with a battery and a bunce of old extention cables using the red and green wires. We could talk on those phones if we both were "off-hook," but I couldn't figure out how to make then ring. I KNEW that it had to be something to do with the yellow wire, but never figured out the formula. Till now..I've learned so much from this series. Please keep it up.
Kelly Parker
Great presenter, having had a fascination in my early years with phone systems, worked on some office
PBX stuff and all over the telecom and networking industry love to see these videos and explaining things showing how it all works.
When I worked a SxS switch in the mid 70's, lightning had hit a major cable fusing at least 1200 pairs together, which locked out other people from getting dial tone by tying up all the line finders/line groups. A fun day indeed. Thank you for this video, it brings back good memories when things were relatively simple.
My Mom went to school to be a switchboard operator,we should visit.
Even in the 80s and early 90s, in a large city on the East Coast, I could still hear a lot of cross talk, messages from other off-hook lines, ringing sounds, touch tones, and other things, while making connections and the other end was ringing, or when leaving the line off hook past the subscriber alert tone. The crosstalk was never loud enough to understand, but sometimes somebody would yell loudly, and you could hear that the distorted high volume voice.
The telco pre-recorded messages playing in the background over top of each other, and those three tones that always played before them, were much more recognizable.
I don't know how this ended up in my feed, but it's really interesting! Thanks!
Fun fact: On a rotary dial phone, if you wanted to take the phone off the hook for a while and not hear the annoying tone, after removing the handset you could move the dial a couple places and stick a pencil into a finger hole to prevent it from returning.
I definitely learned something. In the 70s and 80s we would get a high pitched steady tone if you left your phone off hook. The exchange that ran our phones was a C2 exchange. I had no idea that this would create work for someone at the telephone company. I always assumed it was like a busy signal. The call simply terminated with a tone. It’s interesting to learn that this activity was being monitored. Thanks for the video. Very interesting.
The village I live in got a WE panel office installed in 1965. It was a 4 digit office (2xxx, 5xxx, and 9xxx for payphones) built as a satellite off of a crossbar in the next village. We could only dial 4 digits within our exchange, 7 digits to our immediate neighbors and 1+7 digits to the rest of our area code. Our office had between 7 and 11 senders with no timeout. There were times when off-hook did not give a dial tone.
When I was a kid and I left the phone off the hook for fun hehe , first would come the howler tone then "Please hang up and try your call again, if you need assistance, dial your operator PLEASE HANG UP *NOW*, this is a recording" i had nightmares because it was a very forceful NOW!
I too remember that voice recording for long off hook. It was a male voice, and he sounded kinda mad, like he was gonna visit you personally. "Please hang up and try your call *again*. If you need help dial the operator. Please hang up NOW!"
I think your memory of the exact words is actually the correct one.
12:54 you can tell Sarah knows the machine well because she doesn't even look when flipping the switch to turn off the alarm!
In the early 2000's heard that tone after a lightning strike in my apartment in LA, IDK how it fried the phone to go off hook, woke up to that loud noise and I think an announcement telling me to hang up late at night, had to disconnect it from the plug to silence it. It was an electric cordless speaker phone with an answering machine, never worked after that night. The lightning strike also took out the stove/oven LED panel since it was not grounded (old outlet)
Ah, that tone off-hook sound you played in the start of the video is the same one that Virgin Media in the UK uses, which is apparently different to the one BT used. Funny that it was that tone specifically copied from the US here.
Awesome visiting you all .. great museum
Seems from the user's point of view, permanent signal on the #5XB and the #5ESS is pretty much the same, except the #5ESS will ring once or twice before the announcement. When I was growing up, I had (and still have) a landline served by a #5ESS. I remember I was absolutely terrified by the ROH tone, I would just hide under a bunch of blankets until it went away, and then hang up the phone :)
Edit: interesting side note, after the ROH tone ends, usually this particular #5ESS (or line card) makes a loud, brief "Bzzzrt" sound just after the ROH tone ends, I don't know if they all do that.
You always have such interesting topics. There is so much I didn’t know about the actual operation of a central office. I would say the #5 cross bar was probably the most complicated electromechanical switch ever built.
Pretty soon though you are going to have to explain to the younger generation what a “dial tone” is!
Same way they discover the use of stamps that allow to send mail without "e"
Great video I've always wondered what the effect was of leaving a phone off the hook on the other end! Has the timeout for dropping a trouble card been adjusted for the museum though? In an active office, it seems like it would be using up a lot of cards (and engineer time) if it dropped a card every time someone leaves their phone off hook for 30 seconds.
It’s actually configurable. You can set it to drop for all, some, or none. I set it to all for this demo.
I seem to recall back in the 90s.. when i'd have to leave the phone off the hook for some reason (usually people calling that were bugging us).. it'd do the off hook tone for a while, then it then a few clicks in the background, then a really LOUD howling sound (not the one you played around 8 minutes in), but really howling sounding. Really annoying, but at the time, we had to do it.
4:25 Please please let that be "Oh God Damnit"
I'm wondering if there's anything in that script that covers Emergency situations, like someone tries to call for help but for whatever reason is unable to dial.
i think that's why the operator would come on
I can see how modern advancements would fix that due to the amount of people who didn't care or notice or whatever the phone was off hook. Did the later I know from my childhood if you left it off hook long enough. It would just go dead. But, you would still have to monitor something since once you hang up the phone. That reset the system.
My family would take the phone off the hook if my parents wanted a nap so nobody could call them.
@@silmarian I still do! Nobody gets to interrupt my nap during the day.
I wonder how many trouble tickets I generated as a kid. I know how many trouble tickets I generated for my parents, I could add them to the pile and get a final score for growing up.
When I was a kid in South Africa in the 1970s, if one side didn't hang up the phone, the connection stayed up. That meant that even the side that *did* hang up the phone could not make or receive calls. If you found yourself in this situation, you had to pick up the phone and yell or whistle in the hopes that the person who forgot to hang up would realize it.
Good stuff Sarah, thank you for the UK info also. The comparisons between international ringtones makes quite a curious topic. Love from Liverpool!
I can recall 2 distinct things from movies & TV that dealt with this exact thing...There was a revival of Perry Mason in the 70s and in one episode there was a murder almost caught on one of those newfangled video cameras (the pre-VCR kind, camera knocked out of position so there was only audio) in which one could hear the modern off-hook tone, and it was explained that the phone company had recently switched to that type of tone...leading to the theory that someone called the phone to get the secretary out of the office to go look for the call recipient but the caller just hung up, leaving the office phone off-hook, allowing the murder to occur...Earlier around 1965 there was a film called I Saw What You Did with Joan Crawford, where 2 teen girls babysitting are making prank calls, and one just happens to be to a guy about to kill his wife who suspects the prank caller is his mistress...after he kills his wife and buries her in the yard he returns to the phone, long hung up by the girls, and the off-hook tone is the older 'mosquito' or siren tone, rising & falling in pitch repeatedly. Not sure when that replaced high tone but I remember hearing a short bit of high tone in the 70s just before Jane Barbe would come on...the first time I heard it I was a kid and finally got a dialtone after an outage and was holding the line to see if my parents needed to make a call - then suddenly high tone came on, then the voice recording and finally the intermittent howler - scared the living crap out of me and even tonight watching this video at age 60, I still get the goosebumps a bit at that sound. It is used to great dramatic effect by composer Steve Reich in his composition for the Kronos Quartet, "WTC 9/11"...very poignant and somewhat disturbing but a great piece of music.
Great stuff Sarah! Thank you!
I was always under the impression that the tone was applied continually until hangup. I should note I'm younger so have probably only been on electronic switches. I learned the hard way recently that the ATA in our fiber ONT only plays the howler for a few seconds so I had no idea my phone was knocked off hook.
Neat! I can't remember which phone but I remember growing up one of the phones we had in the house if you put it down a fraction of an inch too far "down" towards the bottom of the base it would not fully press the hook switch so you believed the phone was hung up but it was actually off hook. We'd randomly have where you went to make a call and pick up a phone and either had the beeping tone or a dead line and then have to begin troubleshooting "ok who left something not hung up or what happened". Never know how that worked.
But what if someone had a medical emergency? I would assume that the CO staff would notify emergency services if they didn't hang up at all?
“…if you need help, dial your operator”
Really fun video Sarah. Thanks!
"PLEASE HANG UP AND TRY YOUR CALL AGAIN! PLEASE HANG UP, THIS IS A RECORDING!" I used to get old people who would take the phone off hook and then think about the number they wanted to dial. Then they would pick up the handset and with a shocked look hand it to me and say "Someone is talking on the phone!" So I had to tell them to make up their mind before they remove the phone from the cradle because they were tanking too long.
Fast forward a few years in my telecom career. I get an old lady who has the same issue. So I tell her tocall a number so I can observe what I am sure is her taking too long. Well, she picked up the handset and hit the pushbuttons so fast the DMS couldn't determine the gaps between button pressing. So I asked her what she did before she retired and she said "data entry." So I had to tell her to slow down...Totally unexpected.
Awesome! Hello Sarah! I am welcoming this telephonic distraction from all the other things on RUclips… Let me get a drink and watch this video!
On the small AE SxS exchanges I worked on the in the Army, a permanent off-hook would just hang the first selector and cause a PRS alarm on the frame. We'd have to go through the first selectors to look at the wipers to fins out which line it was. Once we found the offending line we'd put a shoe on the frame from the test desk on the pair looking out to see if it was off-hook, short or water. If it was off hook we'd patch it to a really loud Lorain howler that was much more annoying than the Western howler, if that didn't work, we'd leave the shoe in it and if we needed the shoe for something else, we'd pick out the pair and wait for the sub to complain.
It would be interesting to hear how marine VHF calls where dispatched on on regular phone call
Another problem is when during a say snow storm, everyone wants to call someone. All of the available lines are being used and when you lift the receiver and get no dialtone. All you hear is a side tone, people talking and nothing else.
Heard, back around 1970 or so, in New York City, people would take their phones off hook to make it seem that they are on the phone talking to someone, so burgles dialing their number from a pay phone would hear a busy signal, thus making him think someone is home. Some neighborhoods had a lot of this, and sometimes the office equipment would burn out from overload.
I upgraded my landline to a virtual PBX option last year when i changed my service provider. The little box they give you to connect your old landline phone mimics these features very well. But i do think the warning beep is a bit too quiet lol
That happened EVERY time someone let the receiver off hook? WOW!
Around the 90's I remember a person would also get on the other side to get your attention after all the beeping to tell you to hang up the phone. Around the 2000's it would be a recorded voice. Nowdays it's just the beeping or a loud af tone which I think it destroys your phone in the process. 💀
Im not sure of the 1990s technology with phone systems but can you please talk about dial up internet. and how it tied together with the phone technology at the time!
Actually, one of our other volunteers is going to talk about that soon!
Back in 1973 our hospital had a rotary dial system run by a soon to retire telephone repair man and our company had installed a paging system that would work off that old system I get to see the antique system ....very noisy
I remember the howler. Sadly it is no more on Bell Aliant in Atlantic Canada. I used to have copper landline which was asome our phones always worked even if our power was out for days because of hurricane damage, however when we got fibre to the home for fast internet they switched our land line over to the fibre to the home hub in our basement so now our land line is IP based back to the CO. I now have to have a UPS(battery backup) to keep our land line running. It sucks. Lol there is no howler either if you leave the phone off hook. Just a fast busy signal after 20 seconds. Boring
I remember when I was much younger and living with my parents, we could hear this quiet high pitch whistling noise and we were all hunting around for what was causing it. Turned out to be the phone in the living room hadn't quite seated back properly when it was put on hook, so we'd been given the howler treatment 😅😅.
This would have been late 70s, early 80s UK.
In digital switches the DTMF receivers are provisioned packs, but the difference is that the switch will eventually time out a line and release the DTMF receiver. You can run out of DTMF receivers if call volume goes high enough.
Thank you Sandra I learn a lot from you!
Merp! I really enjoyed this :3
Also, as a vintage computer nut, we definitely have something amazing to obsess over: the 5ESS switch! As you probably already know, it was based off of AT&T's 3B computer systems. Which I'm fortunate enough to own, albeit the desktop 3B2!
I wish that this video had gone into further depth. How were the 30-40 second timers managed? A mechanical timer at each sender? A slowly charging capacitor? How were the special tones and "please hang up" voice unit done?
I will definitely have a field day when I eventually visit your museum learning about all of the stuff that I was so curious about when I was a teenager.
Come visit us for a free tour and you can learn all these things! (Feel free to leave a donation if you think the tour was worth it!)
Man just imagine how many trouble tickets and work was created for the phone company employees just because someone took the phone the hook just so they didn’t want to be disturbed