Many people are familiar with old telephones, but not many people think of the telephone exchanges that they worked with. During the dial phone era most telephone exchanges were of the Strowger Type. The old exchanges were all replaced by 1995. I have however saved enough pieces from scrap to build my own exchange.
My exchange has a mixture of pre 2000 and 2000 type selectors. The pre-2000 type selectors (grey coloured) were made from the late twenties until 1936, the 2000 type selectors (light straw coloured) were made from 1936 until about 1979.
My Exchange is currently being re-built to acomodate all the different pieces of equipment that I have collected. The main 2000 series exchange is now working and connected to several phones around the house. I have just added an extra 5 subscribers uniselectors, a UAX12 line finder with 5 line circuits and an external call intercept circuit. The next step is to connect the pre-2000 final selector to some spare phone lines.
Movie of the upper selector shelf working 451 is dialied to call the grey 741 phone on the top left of the exchange
Movie of pre-2000 and 2000 type group selectors working
174 is dialied to test the bell on the calling phone
(1st digit dealt with on upper rack)
Movie of the UAX12X selector working
261 is dialied with the selector dropping back after the first digit
(digit absorption with discrimination)
Movie of the type 44A ringing machine that generates the exchange tones
I videod this whilst recording the tone sounds separately (at the same time),
then combined the ambient sound (picked up by the camera) with the tone sounds.
If you look closely you can see how the tone pulses
are related to the movement of the contacts.
Some bits of my exchange
Unused pre-2000 mechanism.
A Pre-2000 200 outlet group selector.
A UAX12 selector.
A 100 line pre-2000 final selector.
The Ringing machine, this makes all the exchange tones.