telecom@ucbvax.ARPA (01/09/85)
From: Jon Solomon (the Moderator) <Telecom-Request@BBNCCA>
TELECOM Digest Tue, 8 Jan 85 17:02:53 EST Volume 4 : Issue 144
Today's Topics:
Party Lines
Party lines
party lines
TOUCHSTAR and calling-number displays
questions about touchstar service
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Date: 08-Jan-1985 0146
From: covert%castor.DEC@decwrl.ARPA (John Covert)
To: telecom@bbncca.ARPA
Subject: Party Lines
On two party lines, the technology for automatic party determination has
been available and installed in some areas for ages. It requires a specific
"party determining" set-up which can't be achieved by a layman, or so the
telephone company believes.
In ESS it's even possible for one party of a two party line to have
three-way calling and for the other not to. Call waiting is not offered,
though it would be possible to apply it to the line if the user is the
called party and provide a busy signal otherwise.
/john
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Date: 8 Jan 1985 08:35:52-EST
From: prindle@NADC
To: telecom@bbncca
Subject: Party lines
Here in PA and NJ, the normal hookup for 2 party lines involves use of a third
wire into the instrument which is grounded outside the house. For ringing,
the ring signal is impressed between the tip and ground for one party, between
the ring and ground for the other (thus the designation of tip-party and
ring-party). For calling line identification, the instrument is wired so that
one party (can't remember which) has a phone which imposes a fixed resistance
(about 2400 ohms) between one side of the line and ground whenever it is off
hook (the resistance is derived from the bell coils), while the other party
has a phone which is completely isolated from ground (DC wise) when off hook.
The calling party is identified at the CO by detecting the absence or presence
of this resistance.
The local telco tells party line customers that they may purchase their own
phones but must make sure that the phone can be rewired for party line use
(ie. accept the 3 wire ringing and generate the required identification
resistance); most non-basic-500 style new phones cannot be. The manufacturer
is supposed to provide instructions for the modification, or the telco will
do it on a carry in basis. Even though the mod to 500 series sets is fairly
simple, I've seen an installer botch it the first time. If done incorrectly
you can get strange symptoms like the clapper on the bell ringing every time
you dial the phone or any other extension, or the bell ringing for the wrong
party, or both parties, or the calls you make getting charged to your
party!
Because of these difficulties, most telcos are phasing out party lines by
allowing only current owners of party lines to continue to have them, not
accepting new orders for party lines. It has reached a curious point now,
there are so few party lines in most areas, that those who have them effectiv-
ely have private lines because there is a low probability of finding another
party line customer along the same line with which to share!
Frank Prindle
Prindle@NADC
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Date: Tuesday, 8 Jan 1985 06:05:48-PST
From: goldstein%donjon.DEC@decwrl.ARPA (Fred R. Goldstein)
To: telecom@bbncca.ARPA
Subject: party lines
Party lines have several special tricks to distinguish between
the different rings. 2500-set manufacturers provide several different
resonant ringers, so the CO can send a specific ringing frequency down
the wire and only the right set will ring. One technique is called
harmonic ringing (multiples of 16 2/3 Hz?) and another is called
decimonic ringing (20, 30, 40, 50... Hz). Then you can put the ring
voltage on only tip, or only ring, to ground, etc. Obviously, for a party
line customer to provide his own telset, he'd need to know exactly which
ringer and configuration he needed; the original registration rules knew
that this was difficult so they left it in telco's hands. I don't really
see a huge competitive market for decimonic bells in department stores!
There are also devices that enable automatic number identification
to work on a party line, by some slight-of-hand DC circuit hacks, along
with privacy on calls; the effect is that a party line (up to 4 parties,
I think) can appear to be a single-party line with a poor blocking grade
of service. Northern Telecom builds them for the Canadian market and
I'm sure some US companies have the equivalent, but I'm not sure if they
ever made "Bell System Standard".
Party Lines are no longer offerred in Boston. Massachusetts has a
policy by which every exchange offers either 1MR measured residence
service ($3.24/month) or 2FR party line service (about $6). Party lines
are found in the boonies and a few outer suburbs; they aren't worth the
effort in town where local loops tend to be short.
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Date: Tue, 8 Jan 85 12:30:17 CST
From: Will Martin -- AMXAL-RI <wmartin@ALMSA-1.ARPA>
To: telecom@Bbncca.ARPA
Subject: TOUCHSTAR and calling-number displays
One of the earlier messages about TOUCHSTAR mentioned that the process
that displays calling numbers would NOT display unlisted numbers, and theat
the writer agreed with that design. If this is the case, I think I disagree
with that being a correct implementation.
If someone calls me, by the act of so doing this they have given up any
right of confidentiality of their number. It doesn't matter if they
called me by mistake or intentionally -- when they called me, and
interacted with me, they have imposed upon me, and the least they owe
me is identification.
Up until now, there was no simple way for them to be forced to pay that
cost (e.g., identifying themselves to me by calling number); they could
volunteer it, or respond or not as they chose upon a request for that
information. Now, with the implementation of TOUCHSTAR and similar systems,
they can be compelled to properly identify themselves.
After all, if the system ignores or refuses to display unlisted calling
numbers, what good is the screening and nuisance-call-identification
aspect which is so widely touted? All the caller need do is call from
an unlisted phone. The "boiler-room" scam operations can merely have
unlisted lines, as can obscene or harrassing callers.
Yes, it is true that a business could use this to glean or discover the
unlisted numbers of callers. However, would you refuse to give them your
nunmber if they said "Mr. X is busy, can I have your number and he'll
call you back?"; you might, but in most cases, you called to get some
information, and you want it, so you will trade your number for the
possibility of eventually getting the info you wanted. The chances of
your actually calling a business which you would want to NOT know your
number are minute. You probably wouldn't be calling them in the first
place, unless you wanted to buy aluminum siding or whatever.
Actually, the chances that a business would actually be set up to record
such numbers, manually or automatically, seem slight. Most businesses
don't keep the records they NEED to, much less extra stuff like this!
Will Martin
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Date: Tue, 8 Jan 85 12:15:25 pst
From: hpda!hptabu!dclaar@Berkeley (Doug Claar)
To: 'Telecom-Request'@BBNCCA.ARPA
Subject: questions about touchstar service
I have a couple of questions about the TOUCHSTAR service.
First, I note that unlisted numbers are protected. Does this
include protection from call back? I can see telephone soliciters
getting unlisted numbers so that people can't touch them.
Second, If a store puts your number on their telephone solicitation list,
can you cure them of that by repeatedly calling them, or is that illegal
(I think that it's called attack dialing?)
Doug Claar
HP Computer Systems Division
UUCP: { ihnp4 | mcvax!decvax }!hplabs!hpda!dclaar -or- ucbvax!hpda!claar
ARPA: hpda!dclaar@ucb-vax.ARPA
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End of TELECOM Digest
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