At our next RetroNetCall on August 6th, 2025, we will welcome the former Lead Engineer of the SEL/Alcatel Sytem 12 digital telephone switch. If you have any interest in historical digital telephony switching, don't miss out on this opportunity:
https://discourse.osmocom.org/t/retronetcall-2025-08-06-sel-alcatel-system-12/2246 #retronetworking #isdn #telecom #telephony #telecomhistory

With my article today, discover the fascinating journey of German rotary dial phones and their impact on communication history

Read my article here: https://discovermyeurope.eu/the-evolution-of-german-rotary-dial-phones-from-innovation-to-everyday-necessity/

My new bedtime reading has arrived…

In the UK, AC13 telephone signalling used pulses of 2280Hz to represent the digits of a dialled phone number, call progress state etc.

This training document from 1983 was pretty late in the lifespan of in-band signalling like this, which had been around for 20+ years by this point.

It’ll be fun reading this from a “what would it do if I poked $thing at $time” point of view

Oh yeah! I was posting Christmas telephone stuff this month wasn't I..

On Friday I mentioned that The Hull Corporation telephone company launched their Santa service.

Well, here are three examples of the recorded messages that kids could dial up and listen to:

https://www.youtube.com/watch?v=rI4Gt5YKAWs

https://www.youtube.com/watch?v=zvpTfQCNP7o

https://www.youtube.com/watch?v=wBEmAsACQc4

In 1952, The Hull Corporation (who provided #telephone service in #Hull, UK) launched a recorded message service where children could dial 211211 and listen to Father Christmas tell them all about his festive preparations!

The recording included a message from Santa, carol singing, and stories written and performed by Hull Telephone Department Employees.

There's more info and a lot of photos here: https://www.kcom.com/home/discover/categories/kcom-news/take-a-look-back-at-the-spirit-of-kcoms-christmas-past/

This christmas tree made from a telephone cable was an exhibit at the “Young People's Exhibition”, Imperial Institute, London, 29 December 1936

The cable dates from before PVC insulation was widespread. Each wire was individually insulated with paper, and the whole cable was covered in a lead sheath.

Arranged in “pairs” there are 6024 wires in total.

Photo from BT Archives, finding No TCB 417/E 9977

Christmas at Haywards Heath Telephone exchange 1953

Lots of paper garlands and decorations adorning the CB10 switchboard here, but if you look closely there are paper santas/elves hanging from the cable turning sections where the positions wrap around the corners of the room.

Thanks to Stefan on the "UK Switchboards" facebook group for finding it.

Newspaper article from the "Mid Sussex Times" published in 1949.

These telephone operators at Hassocks (UK) really went all out decorating the switchboard, it's quite impressive!

Thanks to Stefan on the "UK Switchboards" facebook group for finding it.

Happy 31st birthday to the SMS text message!

The first message was sent on this day in 1992

https://m.youtube.com/watch?v=0EEcfKMmvrA

Test shot for a video I’m planning at the moment. I thought it was too pretty to keep to myself… so it’s here with no context

What’s this mystery object stuck to my telephone?

https://youtu.be/F8R8rWIt2yI

Tale of the 1990 AT&T Long-Distance Network collapse. #TelecomHistory #telecom #phone
https://users.csc.calpoly.edu/~jdalbey/SWE/Papers/att_collapse

OsmoDevCall tonight at 20:00 CET: "Calypso chipset history and development boards, from TI to FreeCalypso" by Mychaela Falconia
https://osmocom.org/news/229 #osmocom #telecomhistory #retronetworking

I had to get a silly thing out of my head

Dialling 100 digits of #pi on a GPO 748 telephone from 1971

https://www.youtube.com/watch?v=Z45q-W02f4I

I spent today with a friend troubleshooting the “non-multiple extension phone” relayset he’s built for his GPO HES4 demo

It’s a reproduction of the original “House Exchange System No4” equipment, which is impossible to find these days.

We confirmed the fault, know what the cause is (his electronic #PBX can’t source enough current to operate the differential D relay) but we can’t fix it… yet!

I love the art style on this poster produced by Post Office Telecomunications in the UK.

These posters would have been at least A2 in size, and were available to schools to help teach students how to use the telephone.

I'm not sure of the date, but I would guess late 60s - early 70s.

This poster, and more can be found here: http://www.samhallas.co.uk/repository/documents/wall_charts.pdf

The Museum of Internal Fire have posted an end-of-season walkthrough of their radio and telephone exchange shed.

https://fb.watch/o1LNxL5Ang/

Sorry about the FB link, but I couldn’t find it on any other video platforms

Look Mum No Computer has been rearranging his #UAX13 #strowger #TelephoneExchange to make better use of the space and squeeze in a couple more racks.

It’s a substantial effort to go to, must have been a busy week, but it looks like they got quite a lot done!

https://m.youtube.com/watch?v=tK1lH8pjXTo

One day I’ll make the 6hr drive to go visit…

Got some dirty #telephone #switchboard plugs you need to clean up? You need a Bell System Plug Polisher 497A!

https://m.youtube.com/watch?v=PtGYEqkrYxw

I don’t think we had an equivalent in the UK, but now I really want one!