wb8foz@mthvax.cs.miami.edu (David Lesher) (03/29/91)
{How did *I* get started on this? - I've NEVER had a party line.}
Both Donald and Larry have brought up good points.
First, my BSP 500-114-100 titled "Ringing Limitations" answers Donald's
query. Paragraph 3.04 says
{talking about eight party}
Coded ringing is used to differentiate between
stations....
In other words, it is only "semi-selective" ringing.
While I have not dug too deeply into this aspect, one advantage of at
least the two party Bell method was ANI. While the trick with the
tapped ringer coil added some noise, it DID allow the CO to figure if
Mr. Tip or Ms. Ring was calling Fargo without a "numberpleeze."
The isolators, such as a 28A or a 425A, are gas tubes. They don't
conduct until a LARGE (~90v) dc voltage is impressed on the line.
Ringing is on top of that. Thus, during talking, no unbalance thru the
ringer coil, and less noise. But, if you have a 28A or other of the
myriad items Ma mentions (11A's, 687B's, 425&6A tubes, 426N diodes and
D180036 isolators, to name a few) can you ALSO have ANI, and if so,
HOW?
Here's a mix of old and new: Can you have party line selective
ringing on ESS's?
wb8foz@mthvax.cs.miami.edu (305) 255-RTFMjohn@zygot.ati.com (John Higdon) (03/30/91)
David Lesher <wb8foz@mthvax.cs.miami.edu> writes: > While I have not dug too deeply into this aspect, one advantage of at > least the two party Bell method was ANI. While the trick with the > tapped ringer coil added some noise, it DID allow the CO to figure if > Mr. Tip or Ms. Ring was calling Fargo without a "numberpleeze." So how in the hell did that actually work? I remember that before party lines were abolished in metro areas in the state, the sure-fire way to tell that a friend had a party line when using his phone was by the "tick-kunk" that came immediately after dialing and just before the originating register dropped. Those of us with private lines had no such noise. We all knew that sound had something to do with identifying the tip or ring party, but to this day no one has ever explained what was going on. But going back a little further we find four-party lines. The instant giveaway there was the dialing of any toll call. An operator would come on the line and ask, "Your number please?" Also, participants on a four-party line would find that the phone would ring when the call wasn't for them. It was only to be answered if it was "ring-ring" or "ring" -- depending on the phone number. That little scheme worked like this: The key was the third digit from the end. A 0-4 would be a single ring while 5-9 would indicate double ring. An example was that one friend had the number 296-8122 (single ring) and another 296-4894 (double ring). This pattern even carried over after four-party and even two-party lines were history. Well into the sixties, customers served out of the #1 crossbar offices had double rings if the phone number was of the right type. John Higdon | P. O. Box 7648 | +1 408 723 1395 john@zygot.ati.com | San Jose, CA 95150 | M o o ! [Moderator's Note: IBT has long since grandfathered party line service. If you had it thirty years ago and kept it, you can still have it, but they quit offering it sometime around 1960. If you move, or ask to change your number, that's it! Off the party line you go! PAT]