In a message dated 16 Feb 2007 07:38:25 -0800, email@example.com
> In cities, if you had a party line (2 or 4 party) you had a listed
> number the same as anyone else. If someone called you, they dialed
> the listed number normally and only your phone rang. The Bell System
> used a special wiring technique to isolated the ringers of up to four
> separate parties so only the desired party would ring. (I believe it
> was a combination of bias and grounding). The independent companies
> used different ringer frequencies to isolate ringers.
> However, in many places, party lines had a letter suffix (J, R?). In
> the literature, the panel readout boards had that letter suffix. Some
> old telephone books show that letter listed after to the number.
> I presume in some manual systems one gave the letter to the
I lived in several manual exchanges and one did give the letter to
the operator. This told her which ringing key to use.
I also lived in a dial exchange that had terminal-per-line step
equipment. This meant there was one terminal for each line -- a party
line had an additional digit. The number for my busines was 234.
Individual (one-party) lines had three-digit numbers. Party lines had
four digit numbers, such as 4551. The last digit (usually a 1 or a 2)
told the connector which ringing current to apply.
This was long before DDD or the national numbering plan. Terminal-per-
line had a number of drawbacks, such as the fact that if intercept
service needed to be provided, both parties' numbers had to be
intercepted and the caller asked which number they were called ... also
regrouping party lines required changing one or both customers numbers.
Larger places, and eventually all places, went to terminal-per-station,
which meant the number of a party line was a normal number and the
connector was wired for which type of ringing current to apply.
Eight-digit numbers would certainly be possible before the days of
uniform numbering, although I never encountered any. Tulsa had a
combination of four-, five- and six-digit numbers. Oklahoma City,
originally set up for dial service with all five-digit numbers, later
had some six-digit numbers.
> But in dial systems, did one dial the suffix letter to reach party
> lines so equipped?
> Note -- the above is for party lines of up to 4 customers. I believe
> anything beyond 4 had to be on a manual system and had to use special
> short-long ringing codes. Everybody heard the other phones ringing
> and had to listen if it was their code. (Or they always answered to
> listen in on other people's conversations.)
Not all places had provision for more than two types of ringing.
Others had four, as you suggest. Many non-Bell companies used
harmonic ringing which, at least in theory, could provide for eight or
10 distinct parties with single ringing. Some were more reliable than
[TELECOM Digest Editor's Note: Am I correct in thinking that all
party-line subscribers were geographically close to each other (such
as a few doors away, or across the alley?) Were they nearly or always
on the same cable out of the central office? Or were there party line
subscribers across town from each other? PAT]