Telephone Technology of a bygone era

[davenn]

Hi gang :)

This is not a question thread, rather something I just had to share.
I wonder how many ex- telephone technicians ( like myself) are out there that remember the old "step-by-step" exchanges ?

Here's an AT&T video on how those old systems worked...
http://www.youtube.com/watch?NR=1&v=xZePwin92cI&feature=endscreen

During the 1980's I even had a couple of different model step by step units operating at home. They were PABX (Private Automatic Branch eXchange) units used in businesses. One was a 7 external line and 35 extension unit, the other a 5 line 20 extension unit

The town I lived in/near at that time had a telephone exchange that service some 10 to 12,000 customers. The techs would start cleaning the step by step gear in the racks at one end of the building and finish ~ 6 months later by which time it was time to start the process all over again.
The exchange went digitial in the early 1990's ... some new fangled NEC stuff ;)

As said earlier ... no questions ... just a thread for any discussion and reminiscing :)

cheers
Dave

 

[dlgoff]

This isn't one of those fancy switches.

http://blu.stb.s-msn.com/i/92/CA482CE8BD64BA59DF2F25118C4.jpg

When I was a kid, the telephone company was my source of power.

 

[nsaspook]

We (contractors) won a contract to refurb the RADIO/IC spaces of several older Navy ships built in the late 1950's early 60's with several types of communications systems. One of the systems needing a total rebuild was a Strowger Switch phone switching system. I'd studied how they operated and been inside a few but never worked on one but luckily we had a guy who worked on them as a IC Electrician while in the Navy. This gear had been on the ship for 20+ years and was completely coated with old lube grease and nicotine from smoking causing it to malfunction. The first thing we did after clearing out all the trash from inside was to give it a good low-pressure neutral soap wash (resulting in a foul green-black foaming stream) followed by a rinse of DI wafer. After a complete re-lube, relay/contact alignment (Lots of special tools) and a few wiring repairs the units worked like new.

http://people.seas.harvard.edu/~jones/cscie129/nu_lectures/lecture11/switching/strowger/strowger.html
http://www.telephonecollectors.info/index.php?option=com_docman&task=doc_view&gid=10538&Itemid=2

 

[davenn]

Nice one Don :)

I had a 50 line manual board like that, at home in my museum for a few years ... never got a chance to get it up and running tho.
When i was a kid and my dad a postie in that same town commented on before, they were still manual. Cant remember when they went to automatic... maybe late 60's

 

[davenn]

Hey nsaspook

thanks for popping in... it was your post to the AT&T wave video, in that other thread, that got me looking at a couple of others like the one I posted above

And again you have found a couple more excellent links ... brings back a lot of fond memories :)

Dave

 

[davenn]

Am reminded of another technology that made a brief appearance in New Zealand back in the 1970's ... I personally never worked on these but I remember the distinct sound they made as they were operating...

The Western Electric Cross-bar Switch ... here's a pic of just one switchbank...

cheers
Dave

 

[jim hardy]

Oh My Gosh - i used to work on those rotary switches.
Toward middle of the 1960's we got some miniature ones made in Norway... with small bottles of whale oil lubricant... smelled to high heaven !

 

[HowlerMonkey]

If you want some cool telephony stuff, here is a great link.

http://coldwar-c4i.net/

 

[skeptic2]

I worked as a tech for Western Electric on Step by Step equipment around 1971. The work was testing and fixing complex relay circuits that depended on some contacts opening or closing before others. A large part of the work was adjusting the contacts to open and close in the right sequence.

Once when troubleshooting a circuit, all of the voltages I measured were wrong. Finally I discovered the V+ and V- voltages were reversed. I called the design engineer over and he admitted the schematic had the polarities reversed. The date on the schematic indicated it was 22 years old.

 

[davenn]

...Once when troubleshooting a circuit, all of the voltages I measured were wrong. Finally I discovered the V+ and V- voltages were reversed. I called the design engineer over and he admitted the schematic had the polarities reversed. The date on the schematic indicated it was 22 years old.

Ohh dear haha,

doesnt help with fault finding huh

Dave