DDD at My House
When DDD came
along, the first big change for us was the change out of our 302. We got a new
one and it had a 101B Induction Coil. We were the grounded party. Still on the
party line, we now had "identification" when we called the operator or long
distance. The bad thing about this was that the illegal extension telephone I
had in the bedroom did
not have a 101B coil, so I had to watch what I was dialing, no toll or long
Gradually party lines were eliminated, but the grounded ringing remained.
My favorite trick was to unscrew the F1 transmitter and listen in, the 101A or B circuit then turned into a monitor, but it still put a 2 MFD load on the line.
Back in those days they used a ballistic meter test to determine ringing equivalence. The line was disconnected from the CO Battery and equipment (by putting a shoe in at the protector) and charging the line and then discharging it in a meter. The kick on the meter represented both the distance from the CO (at 0.082 MFD per mile) and the capacitance of the ringers (0.5 MFD per ringer). You were charged for each phone or "ringer" on the line. The voltage used for this test was the Central Office Battery, 48 VDC.
I fooled the phone company testers by using a gas tube to pull in a 110 VDC relay that only connected a ringer to the line when it detected AC ringing. That was when I was in High School in the mid 50's. I could not get the WE gas tube so I used a gas tube voltage regulator (old timers familiar with tube circuits will know that series of tubes, VR-75 or VR-90). Gas Tubes do not fire over (conduct) at 48 VDC, so the meter test did not see it.
From 1944 to 1955 we had only one phone in the living room. I added one in 1955 in my bedroom. A year later I turned it into a pay phone. I found a coin mechanism from a vending machine and with aid of a polar relay I detected line reversal (change in polarity on the phone line when the called party answered as we were step by step) and shorted the phone line, depositing a dime removed the short. So before I graduated from high school I had a good understanding of telephony.
continued reading and still do to this day.