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 operator.
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.)
[TELECOM Digest Editor's Note: No, we did NOT dial the ending letter. All those letters (-B,-J, -M and -R) were merged into seven digit numbers, and tied together in the central office for individualized ringing purposes only, sort of like the 'distinctive ring-ring' numbers today. The parties still shared the same wire (that is, a conversation by one would cause all to be 'busy') but at least the ringing was mostly silenced since the polarity of the ringing was swapped around. The intended party got a full-bodied ring, but the others at best got a sort of 'tick-sound' from a feeble hammer hitting the bell inside the phone. In the pre-dial days, the operator had four buttons with the letters B,J, M and R printed on them on her board, and she would press and hold one of the buttons while pulling the ringing key.My grandmother once told me about hot summer nights in Coffeyville in the 1930's era. People would sit their phone inside or upon a galvanized washtub, to amplify the 'tick-sound' when a 'party line neighbor' got a phone call. All they had were those heavy-metal type phones to use anyway. Hot summer night, all the old biddies sitting outside on their front porch; suddenly in the background you could hear the 'tick-tick ... tick-tick' sound, and after a few seconds to be polite and not appear to be nosy, the old biddies would one by one disappear inside their houses to quietly take the telephone receiver off hook and listen to what the other two were discussing.
And while in high school, my best buddy Dennis Hill called me on the phone one night for a juicy gossip session, replete with some crude conversation about something or another. We had our own private phone line, Dennis was on a party line. I heard the 'click' which warned someone might be listening, and warned Dennis he better shut up for that reason. Dennis replied, "oh, that's just Mrs. Murphy, our party line neighbor; she has been on our line for over twenty years, if she does not by now know all there is to know about our household, she never will figure it out." After a few seconds, another 'click' when Mrs. Murphy decided to restore to us our privacy.
And telco used to also print an admonition to party line subscribers in the phone book along with instructions on how to call your party line neighbor: You told the operator you wished to call the (whichever letter) side of your party line; then you would hang up. The operator would ring that side of the line, and once the ringing stopped then you were to pick up your phone and do the conversation. And if _anyone_ broke into your conversation to say 'the line is needed for an emergency call' you were to PROMPTLY disconnect and wait until the emergency was concluded. And 'to claim that an emergency exists requiring police, hospital, fire or doctor when in fact no such emergency existed, (or refuse to surrender the line in case it did exist) you have committed a class five felony under the law, and will be punished accordingly, up to or including the loss of your telephone service.' Things were different in those days. PAT]