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1A2 signal voltages?

Started by AMCer, July 27, 2014, 12:50:30 PM

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Can someone tell me the voltages for 1A2 signals?

I think the lamp is 10VAC
It looks like the A signal is 28VDC?


Here are the views of labels for a common supply, the 19C2.

With a 117A ringing module it becomes a 20C2, as installed in the second view, which is an installation in a 513A2 KSU panel.

The 117A can actually output over 130 V AC.


The photos explain it all.
The Talk is -24/28 filtered D.C. , the Signal (relay is -24/28 Vdc then you have the + - 10/ 14 Vac for lamps.
There is a +-18/22 Vac for intercom signal (buzzers) and Misc items such as 107 loud speakers, then ringing at +- 105/118
Vac at 30 Hz. The ringing will be a  higher output when there is no load on it. All voltages will be higher that the label shows.
The voltage will be relative to the input voltage (wall Voltage) The system will work without any trouble or changes to tapes on the power supply. If you are new to working with telephone systems I would unplug it while wiring it up. If you touch the ringing  part you will be Shocked and it does not feel good. I've installed 100's of 1A2 systems and in the real world you must work on them HOT. If you respect AC power it's OK to work on with it on. As a hobbyist you don't need it on while wiring it up.
AS a side Note j1 and j2 are combination slots they can have a 10 station 407 dial intercom or 400 d Type Ktu's.
You also need a Field BSP Key system service manual for All of the wiring info. (I do have spares if you want to buy one.