"Jim Redelfs" wrote in message
...
In article ,
Jud McCranie wrote:

I have such a phone and it used to work, but it quit working a few
years ago. Is it really still compatible, because back in those days
I think it required three wires, one was a ground, one was for the
voice, and one was for ringing the bell, IIRC.

Originally, as fed from a Central Office, telephones required only ONE
conductor.

The battery current left the C.O. to the customer's set (many miles was
and
still is common) on a single conductor. There, it passed-through the set
to a
ground rod. The circuit was VERY noisy, requiring that user speak very
loudly
or yell in order to be heard.

It was eventually discovered (1890s?) that if a PAIR of wires is used, the
circuit noise is GREATLY reduced. Try grounding your phone wire while
you're
using it. The party at the other end probably won't be able to hear you
at
all.

Use of "the pair" improved a telco's signaling capacity, too.

Today there are four types of Custom or Distinctive Ring codes: Normal,
two
shorts, short-long-short and two longs. This was standardized in the 19th
century allowing four subscribers to be served by a single line.

The Smith's were a regular ring, the Jones's were two short rings, the
Peterson's were a short-long-short series of rings and the Johnson's were
two,
LONG rings.

This allowed the SIGNALING of up to four users on a single conduction.
The
use of a PAIR allowed for signaling up to EIGHT subscribers. This
technological innovation required the special wiring of the set(s)
connected
to the pair. Signaling current for the four TIP subscribers (with
properly
configured phone sets) was sent down the TIP side of the line, through the
phone and to ground. Ringing current was sent down the RING side of the
line
and would ring only those phones properly wired for a RING party service.
An
improperly-wired phone (often a bootleg) would ring when current was sent
down
EITHER side of the pair.

On old, three-wire base cord phones, the third conductor you describe is
ONLY
for a ground connection in case the phone is wired to ring as partyline
set.

On four-wire corded phones, the second pair (yellow/black) was for dial
light
current fed from a small transformer somewhere in the home.

It still only takes a PAIR of conductors to service a POTS (Plain Old
Telephone Service) set and it has been that way since the late 19th
century.
All the other wires are extra.
---
Replace you know what by j to email

Your sig delimiter is incorrect. I just described the proper syntax in a
previous article. Good luck!
--

JR

Where are ya, Ma, when
we really need ya?

Good information ! The only thing you didn't cover is ECHO.


Happy modeming;
Bill