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After about 4 years (things move slowly out in the country), I finally have begun wiring in my Tone Commander intercom. It's a common talk path, dial-selective unit and I'm connecting it into my Stromberg KSU (for which I have no documentation, unfortunately).
The intercom requires from the KSU only A battery, B battery, audible signal source (could be ringing voltage or buzzing voltage), lamp battery, and associated grounds. I did not have enough spaces in the KSU for the B ground, so I used A ground for that, since they are tied together in the KSU. Inside the KSU, I used AB, AG, BB, AG, 18V, 18G, and 10V respectively.
I have these punched down using solid copper CAT-5e, since that's all the pairs I need for this, and for a small residential installation it seems like the best option. I document my color selections in order to keep my brain straight and not reverse anything. The intercom breaks out from an Amphenol connector on the side to an M-style block. From there, it goes directly to the blocks built into the KSU.
I have one phone in the basement, about four feet away from the intercom and punched to the T/R, Lamp, and audio output pairs marked on the intercom unit as station 0. I have another phone in my office on the first floor punched down on the M style block as station 1. The office phone also has lines configured for two 400 cards handling our C/O home line and a VoIP line.
When I pick up either phone and select the button I've designated for Intercom, the lamp lights on both stations. In the basement receiver, I can hear the other party (my daughter, who thinks this is great fun!) but there is a roughly 120Hz hum that almost obliterates the audio. Tone dialing doesn't work to signal the basement station, but rotary dialing the office code from the basement buzzes in the office. I am assuming at this point tone dialing doesn't work because of the hum on both phones.
I don't think I'm inducing electrical noise into the wiring, but only because I have two other lines to the office phone that work fine. This sounds to my ear like I'm restoring one of my antique radios and there's a bad power supply filter. Has anyone seen/heard anything like that, and is it possible I'm getting unfiltered voltage into my talk path?
Thanks for any guidance and help you can provide. Once I get this licked, I'll be 8 pairs out to my garage and finishing off the garage/workshop phones and have intercom in all three locations. Then I'll probably unlock a spare line key on the phones and wire them to open the garage door.
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