Ericsson AGF telephone exchange 500 line selector demo

The Ericsson AGF telephone exchange was used all over the world for more than 50 years. The key element of these exchanges is a 500 line selector. This is a demo of the operation of such a selector. The missing parts are simulated with an Arduino microcontroller.

[@jrb_sland5066]

Thanks for this video! I'm an elderly {74} Canadian man who is more-or-less retired from designing & manufacturing {in my tiny home basement office & workshop} specialty electronic equipment for the geophysics community. I was entirely unaware of the Ericsson selector until this video. A very clever design, and quite possibly superior to {more compact than} the earlier Strowger step-by-step mechanism widely used in North America beginning in the late 1890s. The lesson we learn is that there are inventive people all over the world. God bless all of them - we stand on the shoulders of giants, to quote Sir Isaac Newton.

[@stephenbamforth1514]

Thank you for this video, I was originally a Strowger BT Technical Officer in South Yorkshire UK. left BT as an Ericsson AXE10 engineer and became a consultant (1998) at Ericsson Stockholm Network Operations Centre. I came across the bank system as part of demonstration at the Museum of Engineering in Stockholm whilst working and living there. Fascinating how both Strowger and this system had group and final selectors but used differing mechanisms as you have indicated the design of these systems was admirable. 🙂

[@kreuner11]

I see that it can only use one phone at a time, how was this deployed to allow for more then one phone call at once? If we had the maximum 500 phones you would have 500 switches and each phone would need to be connected via 500 wires in a horrific mess of cables, which I don't think is practical

[@akovalick]

Well done! A clear explanation of how the Ericsson pancake switch works. Using the Arduino with relay drivers is a great way to do the demo. Thanks for doing this.

[@sethreeder4264]

I remember as a young engineer working with AGF in Stavanger Telephone Exchange. I saw it later in a technical museum in Stockholm.

[@Cheva-Pate]

The best thing was this system worked even if you had a local black out, you could use your phone.

[@jmcbike]

I like the description. Amazing it was originally built without electronics. I recently did a project that rings another rotary phone; the Arduino counts the dial pulses, switches 12 volts from powering the line to powering the ring generator, and sets the correct line selector relay to ring the other phone. Between rings, the Arduino checks for off hook voltage, if so stops the ringing.

[@nealwalker6277]

Hi, thank you for this video, I have an old GSM 900 car cell phone (1993). In my country, 2G is no longer available, so the phone does not work anymore. I tried to find out if it would be possible to convert this phone to 4G, unfortunately I couldn't find anyone who could help me. What do you think, is such a conversion possible?

[@Linkvagen]

Thanks for a really good description and demo of the 500 selector.

[@standarddeviation6428]

Love this! Hope more people see it :-)

[@wouterke9871]

Beautiful ! Knap werk en mooie demo van deze pannekoek 👍

[@dave-j-k]

Amazing, thanks for the demo, its a work of art :)

[@jasona716]

That's fascinating, thank you. I've never heard of those devices before. Very nice demo.

[@mglenadel]

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[@marklatimer7333]

How did the system work before the invention of an Arduino?

[@gaborm4767]

Does each user have their own selector?