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From: hpa@casbah.acns.nwu.edu (Peter Anvin)
Newsgroups: comp.dcom.telecom
Subject: Re: Touch-Tone Specifications
Message-ID: <16015@accuvax.nwu.edu>
Date: 12 Jan 91 08:37:01 GMT
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X-Telecom-Digest: Volume 11, Issue 29, Message 6 of 10


In article <15966@accuvax.nwu.edu> rees@citi.umich.edu (Jim Rees)
writes:

>>5. Get a phone that supports all four RJ-11 wires (including black/yellow).
>>   Swedish Televerket warns that a "pirate" (non-compliant) telephone may
>>   not hang up properly, running up your bill long after you hung up.

>I know of at least the following uses of the "second pair" (yellow/black):

> - Off-hook indication for key sets.

  [List of other uses deleted]

>Which of these does the Swedish system expect/use?

I would presume the off-hook indication, since what Televerket
complains about is that non-"T"-certified (remember, Televerket is
like FCC and pre-1984 AT&T combined) phones may not hang up correctly.
In Sweden, a phone call is not necessarily disconnected unless *both*
parties hang up, thus you can: 

1. Ask your party to wait, hang up, and grab another phone somewhere
else (there is a timeout in most areas).

2. Trace a harassing call even if the harasser hangs up.

Also, in Sweden the indoor wiring is serial, not parallel, meaning
that if you lift the handset on one phone, you disconnect all phones
with lower priority, i.e. further away from the incoming line.  This
looks to me like it almost has to be some form of on/off relay here?

(Maybe someone at ericsson.se knows...)


H. Peter Anvin +++ A Strange Stranger +++ N9ITP/SM4TKN +++
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