56k and 33.6k Modems Connecting to Each Other with no Phone Service
HTML-код
- Опубликовано: 6 сен 2024
- Playing around with old dial up modems and retro PC's, establishing a connection over a phone cord without a phone service and transferring a file to test the connection.
I used one modem on a PC RS-232 port, running the old Telix modem software in DOS.
The other modem was connected to a slightly more modern PC with a USB to RS-232 Serial cable, running MiniCom in Linux. According to Wikipedia, MiniCom was modelled after Telix.
en.wikipedia.o...
Telephone tech resources:
www.hermonlabs...
(if link is down, try pdf4pro.com/vi... )
en.wikipedia.o...
electronics.st...
www.gutenberg....
Patreon: / gadgetreboot
#ElectronicsCreators
Impressive! It was indeed gratifying to see the CONNECT message, particularly since it was accomplished with things taped to a desk. I believe this is also the way E.T. really phoned home! 👽
I miss the sound of modems connecting... It was so satisfying to see them connect and see the BBS appear (unless you ran the BBS (like me) and turned the volume off) hehe!
Nice project and video. 👍
I always kept the modem volume on, even when I ran a BBS. It was always strange when I upgraded from a 2400 to a 14.4 modem and I would still have days where I would call a random new BBS number and it connects at 1200 and it’s running on a Commodore or something. The text would peel on slower than I could read, and it wasn’t even ANSI graphics, just plain white text.
I like the hiss that came just after the tones, then you know it's connected. but all that said I don't miss the speed or lack of it. just missed out on the plugging your handset in to the acoustic ports on the modem.
woah nested parentheses you might get a syntax error
Ah, the ol' Hope, Pray, ... and Wait ... for the disconnect brush-aside from your dial-up Internet service provider!
I the early 80's, I had an Atari 1200XL with a cassette tape drive and a 300 baud modem. I would connect to several local BBS's to talk to other users and download games. Ah, the good old days. If you think about how far computers have come since then, I can't wait to see what we'll have in another 30-40 years.
It was always fun discovering a new BBS phone number and calling to see what they had to offer. Of course it was always awkward when the phone number was no longer a BBS, or it was a part time BBS and you were calling when it was used as a voice line and instead of a connect squeal, you heard somebody saying hello? Hello? Hello?
Excellent work! If I remember correctly, some modems, especially courier and USR Sportster has “line driver mode” where they would be used on a leased “dry copper” circuit like a series 1000A fire alarm circuit. Might be worth a Google!
FYI - if you ever buy a second 56k modem, don’t waste your time trying to get them to connect at 56K. The ISP side has to be using ISDN (usually PRI) in order for the v.90 modulation to work.
very true, i was going to post a message about that but you beat me to it. 33.6 is the max you can get with the bandwidth of a pots line.
I wonder if anyone actually tried with a short line like this. I've seen a project, a long time ago, that managed to do over 100kbps on short lines analog lines using a sound card connected to a hybrid circuit. In this short run the signal will likely be clear enough to attain 56kbps, but I have no idea if the modems even try to, after the initial handshake indicating a scenario where 56k wasn't supposed to work.
Watching this, I had a flashback to the classic movie - War Games.
All you needed was a phone receiver modem.
yeah, 6 hours download for 20 MB star trek game demo, last century ...
I started out on a 2400 modem and it was one thing to locate BBSs that had “Elite warez” but then I had to find a place that would tolerate me tying up the line at such a slow rate. I remember it took about 15 minutes to download a 212 K zip file.
you had a fast connection 3mgb took me 6 hours i only had 28.8k my first modem was a 9800 baud
Back around the turn of the millenia, it took me a whoopin' hour to download a 10.4MB zip file containing the correct drivers for my VooDoo3 3000 grapbic card. Only then was I able to play games such as GTA2 and Half-Life. My parents were all but pleased to have the single phone line tied up for that long. Luckily, no one dared to pick up the phone during download, I would certainly have screamed my head off because of having to download that file again!!
I was born in 2003 so I've never been able to use this stuff but I still find this kind of stuff really interesting. Thanks for sharing your knowledge!
I have done several updates on this project and in the most recent one I got a phone from the 1960s working and that was before I was born. ruclips.net/video/mfYOpV_lOho/видео.html
A few years ago, I also used the 9V battery circuit to help out a friend who was trying to extract data from an old Mac with a modem. Quite a good feeling to see it work! You are doing well to get two of those old modems to connect at 33.6K. Gosh, these devices were finicky, ran hot, and broke all the time. I had a couple of jobs managing banks of them on servers with octopus serial devices. Constant issues.
When I went to dismantle that set up yesterday, the underside of both modems was very hot. I remember there were those special COM port expansion cards that had at least eight serial ports, I forget what that was called. I guess all the multi node dial-in systems had to have those if they had more than two nodes or so. I guess they could have two internal modems on com three and four and two motherboard comports one and two before they need to get fancy. IRQs were scarce
@@GadgetReboot I worked at Pipeline Communications, that took 1-800 dial-up software registrations, games mostly, before the Internet was a big thing. Had external modems, because they were easier to replace when they went funky. A bank of fans blew on the modems, and the whole room was air conditioned to a frigid 60F. We called it the "ice box." The servers used things like this, but on an EISA bus: www.startech.com/Cards-Adapters/Serial-Cards-Adapters/8-Port-Native-PCI-Express-RS232-Serial-Card-16950-UART~PEX8S952
I just remembered the multiple serial port interface I had heard of in the 90s, affiliated with major BBS software commons.m.wikimedia.org/wiki/File:Galactiboard_01.JPG
@@GadgetReboot RocketPort was the most popular one. They had an IRQ handler IC onboard and a driver to sort it all out.
I find US Robotics 56k modems in network racks to this day. Sometimes at businesses that have not had POTS lines for a decade!
You could make a real phone line using an Adtran TA904. Build two FXS interfaces with phone numbers and they’ll be able to dial each other, get ring voltage, and answer normally without having to jump through hoops with special S register tweaks.
My usual blind dial method was ATX3D
If I was on the phone w/ a friend and we wanted to switch to modem for a game or something, one of us would type that and the other would type ATA.
Hence the origin of the null-modem cable! Great video!
The baud setting in Telix is between the computer and the modem, NOT the line speed between the two modems. Back in the day, you would never try to match the baud setting on your terminal program. Instead, you set the highest baud that the modem and the computer can communicate at; ideally, that will be higher than any speed the modems can connect to each other. @4:28
This is excellent!
Around the year 2000, I was able to accomplish a link between two Windows 98 computers using a synchronous null-modem cable and a dialup connection. TCP/IP was running also over both computers and the host with ICS worked like charm with a speed of 14kBytes when transferring files between the computers or from the Internet.
Even with 2x 56k POTS MODEM you wouldn’t achieve 56k logins, as the 56k mode needs a digital adapter on the "offering" side, i.e. an ISDN device that acts as a 56k host. Direct analog connections between 56k devices will always end up with 33k6 connects. Everything above 33k6 needs e.g. an USR Courier-I (I for ISDN) or a ZyXEL Elite 2864 ID (again, I for ISDN).
that makes sense. It’s still better than what I was ever using, I started at 2400 and graduated to 14.4K and around the time dial-up was disappearing I bought a refurbished 28.8 K Motorola but the fun was over by then.
In the 90's I needed to test various MODEM's for use with leased lines (point-to-point twisted pairs with *_no_* line voltage) for a national stock exchange I was working for.
I found plenty of MODEM's would not work on leased lines, even including those advertised as being capable of working on leased lines which lacked line voltage. The one MODEM I did find which not only worked, but was rock solid at keeping the connection up, was the US Robotics Courier V.Everything. So we decided to deploy them.
Those USR V.E MODEM's could stay up literally for years, non-stop.
A lot of these old modems had a private wire option configured through an at command option. If you find this and enable it you will be able to connect them back to back without the current source. They will then just go online as soon as they see each other without needing the ata or atd commands.
I remember reading about that on some US robotics modems but I think it was only special ones like courier HST type things, not sure. I wonder if I still have that tab open somewhere. I do plan to do a deep dive on all the options though.
@@GadgetReboot Use a Null Modem Cable
@@wooferhound7571 A null modem cable does not help. It could only be used in place of the two modems which rather defeats the point of it all..
I've had success connecting Multi Tech Multi Modems back to back. I guess they have enough logic in them to automatically work around no line voltage. The only thing I believe is I had to turn Dialtone detection off with the AT command ATX1
I was searching a way to connect computers using telephone lines as they are in all my rooms. Loved you took time to share this video.
Instant sub. Man, do I appreciate you doing this.
Edit : OMG the Telix flashback tho.
I'll be doing more things with a custom made circuit board at some point where I just plug each modem in and simulate a phone line more authentically but not fully (no actual high voltage ringing). But I'm in the process of moving so that will take months.
I had no idea this was possible. I thought you were required to have a PABX. Great work!
connecting 2 56K modems together will not allow 56K connections, only 33.6 as 56K requires a special dial-up server operating over ISDN.
no it jumped to 33.6 if he used the 14.4 it would jump to 14.4 as the handshake determines the slowest max speed,
my dial up would do 52k and direct connects is possible for 6.4+ but yeah it could be a isp side for the v.92 56k stuff...breaks out modems!! i do know one thing for sure lucent chipsets modems would give you almost a -100ms ping to a us robotics..but us rules the download
Surely there's enough SNR on this short run to get 56k, but I wonder if the modem firmware even bothers to try if both sides report being connected on an analog line during handshake.
In theory it can be done, an analogue 56k remote access server can be developed from scratch if someone knows how the system works and how to implement the system. Almost 99% of all 56k servers use digital modems and must be connected over ISDN - T1/E1. The digital lines are then translated over to analogue at the exchange before reaching the customer. One way I know to make a DIY 56k server is to use a dedicated 56k remote access server and use an ISDN-FXS PSTN simulator, which translates the ISDN to analogue in much the same way as a telephone exchange. Such simulators are very expensive and uncommon but if you are lucky, you can find these units from telephone exchanges that are throwing their old equipment's away. I know of one model which is listed at over $2500... Not something i can afford based on the use it will receive being only for the fun of it.
@@Ali6359. I wasn't expecting such a quick and informative response on a two year old comment. Thanks!
How fun it is to get something this simple working. I like this video.
This was epic! Loved the sound followed by "CONNECT". Nothing beats that!
You can add the init string ATZ and command ATX3D for the dial modem and to recive modem put ATA. This work with direct phone cable connected.
This guy learned the language modems spoke and became friends with them
Good video, you proved to me what other sources didn't make very clear, which was the fact that you need a current on the phone line. My setup works now, thanks!
Modems supply voltage on the phone line port so they can be connected directly together phone line to phone line.
ATDT(any number) on one, ATA on the other...I've done it many of times.
If you want to simulate 2 real phone lines so you get "ring" signalling use a cheap voip adaptor (like a PAP2T) and set it to do IP dialing so one line can call the other... To dial on some you have to turn off dial tone detection.
I was looking forward to this!
Hopefully there’s lots more coming, possibly even a custom PCB design if I make it that far in all of this. So many tangents yet to come. I can’t believe I think it’s about a year and a half since I did my last modem related video. I can’t let that much time pass again.
@@GadgetReboot Good deal. Looking forward to more tests.
You could install pppd on the linux side and serve the Internet. Check out www.steptail.com/guides:virtual_modem
Thanks so much! I was looking all over for something like this. Now it's time to see whether an ancient 300 bps modem I found still works. 🤔
I always wanted a 300 bps modem from the old radio shack catalogs but I started with 2400. It was funny radio shack marketed their 1200 as high speed, and with my 2400 I couldn't connect to elite BBSes because I wasn't 14.4 high speed. Until one Christmas!
Great Nostalgia project !!!!! I will set the handshake sound as my ringtone on my cellphone LOL
Helpful video 👍
Great video :)
Thank you for sharing. This will for sure be helpful to setup retro computers with each other OR simulating a project before putting it on an actual landline provider. :D
i’m currently trying to work on making a more elaborate phone line simulator and so there will be more videos coming.
Back in the early 2000s when I was a child we had a dial up modem I believe
Triton internet flashback! I'd prefer these old reliable modems over the terribly-serviced Spectrum any day! (Too bad I'm stuck with Spectrum for now...)
A great video! Thanks for sharing! I remember my horrible experience with dial up. Had some horrible service called Busprod then later changed their name to bpsinet or something like that. After they went out of business went to egix, inc. Horrible service! Seemed liked every time I would turned around blinked my eyes. I was always getting disconnected for some reason! It was so annoying! Trying to download any large file was almost impossible! Using programs like emule was totally useless with dial up. Can't say I have not missed dial up!
The main thing I didn’t like when I got my first 2400 modem was taking about 15 minutes to download a file just over 200 K. I didn’t really have ISP disconnect issues, it was more a problem of other people in the house picking up the phone and causing disconnections.
Excellent work and video!! Looking forward to your future videos!
Ill have to break out my us robotics modems! Leased line
Thanks for this video. Brings back good memories.
But, when I and my friend ware experimenting with connecting two modems in the same room we (almost) didn't need any voltage or current source on the fake internal phone line for this to work.
Our setup was:
-two PCs with PCI modems
-real working phone line
-dad's old Ericsson mobile phone
-one phone cable with RJ11 connectors
Only problem we had was that we didn't know how to force one modem to answer a call manually (skip ring signal detection) because we ware using a multiplayer game (Colin McRae Rally I think) not terminal so we couldn't use AT commands directly. Then I came to this idea: one modem will be connected to real working phone line waiting for the ring, other will be ready to make a "fake" call to some random number, then we will call our real phone number with mobile phone and wait for first ring after witch first modem will answer the call. In about the same time we will start making the fake call from other modem so when first modem detect a real ring signal we will quickly disconnect it's cable from the real line and connect two modems directly without any voltage or battery in between. And this was working perfectly except some times when we ware too slow to disconnect real phone line form first modem and that first modem answers the call billing my dad's mobile phone which was not cheap back in the time.
Sorry for my bad English ;)
Might be a fun project to create internal home ISP to connect old computers to wonders of world wide web
Really fun experiment! Well done!
Planning on setting up a BBS so you can plan L.O.R.D. or that other game who's name escapes me?
If I get the project far enough off the ground, I do plan to see if I can get my old BBS running. It’s currently a fossil from the mid 90s when I zipped it up. I did play LORD and some others that escape me as well, I think one was global war but that’s not what I’m thinking of. But the other one that people used to play would be trade wars and I never really got into that, I don’t remember if I even gave it a chance. Also remember playing
Barren realms elite, Solar realms elite, pimp wars.
And of course if I was directly transferring files with somebody using bimodem, I think we could play Tetris and chat while waiting for those long transfers.
@hmx Tradewars? That’s the other one I miss. :)
Kyrandia? Trade Wars 2002? ... Lemonade Stand?!? The possibilities were endless. ;)
Nice project!
I keep seeing the 9volt battery thing but I might like to use a wall adapter or some pc source for this. interesting video, any updates or followup videos after this? maybe i missed one (I scrolled quickly). Definitely interesting channel :D
I think last November I put out a video with a more modern way to get a phone line simulated but I’m also currently working on something that I expect to have a video for in September, this has been an ongoing theme and it’s all going to come together soon.
congratulations
you created intranet
soon I’m going to expand upon it and I’m going to call it super internal fake net
Pretty amazing work!
That's Brilliant!
Wow!! Excellent Really nice video!
I have an idea why your current calculation required such a low resistor. In the series arrangement (Modem A - 9V - resistor - Modem B), you've got one current path at 20mA. If the 9V source is connected in parallel like you have, what you're doing is making two separate loops, with 20mA passing through each Modem A and Modem B but needing 40mA current in the central leg being drawn from the battery. That's why you need a resistor with half the resistance you thought you did.
The difference between the two is with the battery in series then the modem signals have to push against the battery to transmit anything (so the capacitor across it helps the wiggles get through). With the battery in parallel there's no (added) resistance in the loop between Modem A and B, so the transmitted wiggles can transmit easier. Do you think I'm on the right track?
QUe curioso eso, yo me acuerdo en mi epoca de los 90 hacia estos tipos de experimento y en algun momento concte dos modem de 56k directamente por cable sin bateria y si funcionaba colocando el comando ataa y funcionaba sin porblema.
I always get NO CARRIER, voltage is 9V with resistor 56Ohm. Please help!
That was awesome
Is there a way to automatic answer when you try to dial in? So someone doesn't have to be there on the other end.
I’m working on a new project that I plan to make a video for next month to simulate an actual phone service where both modems can plug into jacks as if they are in separate locations and one can call the other like it’s 1999, and the one on the receiving side can automatically answer. I am going to test it out by setting up a BBS on one computer and dial into it with another computer.
@@GadgetReboot nice. I can’t wait to see that.
Amazing 🤩
I don't think you need to emulate a Phone Line if you use a Null Modem cable to connect them together
I can do that directly between serial ports but then I don’t get to use the modems so it defeats the purpose of the project.
Nice video, actually I could connect my two USRobotcs internal modems, by a simple direct rj11 cable.
luxury. Mine definitely don’t work when directly connected but that makes it all the more fun. I am currently working on an entire telephone simulator where I can plug in two modems and actually dial one number and have the other answer like a landline.
I'm curious about your mention of future projects with these, have you done more experimenting?
I have an ongoing project in mind that I occasionally add notes to or do more research on, but right now I'm in between moves so I need to get settled (starting in the fall 2021) and get access to all the old computer stuff that's in storage since last year. I plan to make a custom PCB so I can plug in the modem phone cords and it would simulate a phone central office and allow calls between the two things etc.
@@GadgetReboot PLEASE DO! Very interested in your progress here, thanks for bringing back fond memories!
but... remember when.. it took
I am trying to get this setup working between a USR 56k modem and a Racal-Vadic 2400pa; as far as I can tell, the 56k does support speeds all the way down to 300bps if needed. I can't seem to get the 2 modems to talk to each other at any speed, with "ata" I can get the 56k to start a high pitch tone, but "atd" on the 2400pa will just cause the relays to click, then will temporarily stop the tone on the 56k, before eventually returning "NO DIAL TONE", and the 56k will eventually say "NO CARRIER".
Have you ever had success with getting such old modems (1987) to connect with the more modern ones? Or do you have an idea what the problem could be?
I've only tried doing this with the USR external 33.6 to 56k but one problem could be the dialing modem is waiting for a dialtone, which won't exist with just the battery current source, so instead of ATD try ATX3D to tell it not to wait for dialtone
Rs232 isn't the port. That's the protocol used. Call it a serial or at least DB9
Hand me a Kleenex, my Thermos leaked all over the Xerox I made of my documents, and dripped onto the Linoleum floor. I should have used Saran Wrap, Velcro or Super Glue to keep that shut, or just put the coffee in Tupperware. I'm just going to go to the Jacuzzi and forget about it for now.
Couldn't you use a Tone Generator "Tempo" is one that comes to mind.
Do you have a playlist for all related videos? Very interested in this modem to modem without phone service topic.
I think there’s three modem videos in this playlist along with other older technology experiments. I have plans to do more modem things when I dig out some ancient computers and I plan to make a little phone central office project.
ruclips.net/p/PLDnEejiR3mBxEdca8N6daF0HA-GGYFZ0r
Thanks, I'll check out the playlist. I got the phone to phone intercom part working last night, but I couldn't get modem to modem working. I kept getting "NO DIALTONE" and "NO CARRIER" when I issued the AT commands into TeraTerm.
impressive!
Oh, can't link them over a direct phone line :(
Gosh I want to set something up like this. How could one do this with very few resources? Could I hypothetically buy a pair of softmodems and just wire them to each other, then control them manually? I can never find any proper softmodems, they all seem to be from no-name, untrustworthy companies.
there are certain modems that support directly connecting to each other without a phone line or simulation circuit but I’ve never had one and the only way I could get modems to connect is having The battery to provide the same loop current that a landline would provide.
this is cool
Try a dwango dialup deathwatch with doom
I plugged my modem into the land line and I tried dialing but there was no sound :(
I forget if a modem even needs to see an active landline in order to try to dial but assuming the landline works and the modem works, maybe just a different initialization string is needed to make sure the volume is on and maybe make it not wait for dialtone, I can’t remember all the AT commands now but ATX3D sounds familiar for maybe not waiting for a dial tone
@@GadgetReboot what would you suggest I do to get my modem to make the iconic 56k modem noise on command? I had do move my pc in the kitchen to plug it into the phone outlet because I don’t have one in my room and I don’t want a big dial up Internet server in my room. I have a us robotics gaming pci 56k v.90 modem.
I don’t have my stuff set up to do any testing right now but if the phone line you are plugging into is not active you might need to provide power to the modem with a battery.
But the first thing I would try which would be the easiest is to look up modem initialization commands to not wait for dialtone before dialling and to make sure volume is up and if that doesn’t work either the modem doesn’t work or it needs a powered circuit or a phone line
@@GadgetReboot I don’t use the land line for anything so it’s definitely not active but the modem is brand new. Also the volume is on high. Would a land line simulator be able to send a dial tone to the modem?
if it’s a proper simulator then it should because that would be part of the main purpose of it but of course if there is a product calling itself a simulator I would read all of the specifications to see what It can or can’t do. some of them are strange things maybe only meant to be used as a telephone intercom so you pick up a receiver and it sets off a buzzer on the other side and it’s not really a true simulator.
When nuclear war / zombie apocalypse wipes out everything, you're ready! :)
couldn't you just look into how to Disable Carrier Detect?
These modems don't work on a dry loop so they need something to liven it up first.
If the internet cut out and no one had it to connect to anyone.. Could you whip this bad boy out? (Obviously I am not technical, just curious)
If people went back to the pre internet days and everyone had these kinds of modems, and land lines, yes! I wonder if there's a way to adapt it to work on a cell.
@@GadgetReboot Too much compression on the cellular network. Best you'd be able to achieve would be 9600K, if not less. Yes there are wideband codecs in use now but they seem to still have far too much compression.
Imagine using dial up modems in 2019 ☺
I might end up trying that if I can figure it out, although it might take until 2020.
Well you know you can just connect a RJ11-write straight through with no power at all.
Omg. Windows ME??? You're kidding?
Windows 98 SE is probably better for this stuff, more time period correct and should have all needed drivers and not losing control over hardware as the OS kept evolving. I don't know if I have Win 95 somewhere, that could be even more appropriate.
or win 95 se with IE🤣
This is way too much work. It’s 2022. Leave this behind.