JoeOfSeattle@yahoo.com (Joseph) wrote in <telecom24.58.6@telecom-
> On Sun, 6 Feb 2005 11:14:23 -0000, Paul Coxwell
> <firstname.lastname@example.org> wrote:
>> 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.
> This is generally the case only where the equipment used was "terminal
> per line" as opposed to "terminal per station." In terminal per line
> set ups the last digit always indicated the cadence of the ringing
> with 10 possible combinations for both tip and ring side of the line
> so that it might be possible to have 5 different ringing cadences
> depending on what your number is e.g. the last digit of 1 on the ring
> side of the line you'd have a single ring, 2 two rings, 3 one long and
> a short, 4 one long a short and a long, and 5 being five short rings.
> Repeated for the remaining digits on the tip side.
> In terminal per station you could have any ringing combination but it
> was determined at the central office (switch.)
>> 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.
> Mostly used by independents rather than by the Bell System.
>> 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).
> On two-party lines whether it was tip or ring determined whether
> either party would be charged and you could use AMA. With four party
> you used CAMA and an operator would come on the line to ask what your
> number was.
> Independents used "ID" digit.
When I started here (1970) we had a Federal stepper. The
terminal-per-line shelves used the second digit of the station for the
ring digit. For example 5195 was party 1, 5295 was party 2, etc. up
to 5095 was party 0. We had five frequency grounded ringing
(Synchromonic) so each party only got their own ring. Circle digit
toll ID was done with North Electric "Autollizer" The sleeve lead from
the line was connected through a diode to ground via a jumper that
went through a "ring field" When the customer dialed the circle digit
a current spike flowed through the jumper and induced a voltage in the
coils of each ring through which the jumper was run. This identified
the line in a register/sender that was incorporated into the toll
trunk. Billing info was sent to a tape punch at the end of the call.
Tapes were "read" once per week in small offices, daily in the big
offices, and 90 column cards were created for shipment to the data
center where bills were produced. The C.O. was a noisy place then.