I'm interested in getting some more detailed historical information on the way party-lines were arranged years ago.
Here in Britain with our relatively small area and comparatively high density of population, a two-way line was the norm with ringing applied to tip or ring and bells connected from one side of the line to a local ground. Outgoing calls used a ground-start method, with subscribers having to press a button to obtain dialtone. (As even local calls were charged, this method enabled the C.O. to determine the originating party at the outset.)
I've gleaned from various sources, including some old Digest posts, that in the U.S. there were various methods employed, including up to
10-way party lines with the last digit of the number selecting tip or ring and the appropriate ringing cadence. I've also seen references to tuned ringers with ringing applied at a different frequency for each party, and to party-line numbers having an additional digit (coded as a letter) added the end of the regular number.When it comes to outgoing calls once DDD and CAMA had arrived, I've seen references to different ringer wiring combinations to enable the equipment to test for originating party, and also in the earlier days of DDD that in some places (maybe small independents?) callers had to dial an ID digit (e.g. 1x + NPA + number).
Can anybody elaborate and explain in more detail the arrangements which were commonly used, both in the Bell System and in the larger independents?
Thanks,
Paul