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From: john@bovine.ati.com (John Higdon)
Newsgroups: comp.dcom.telecom
Subject: Re: Thoughts on 900 Service
Message-ID: <11448@accuvax.nwu.edu>
Date: 27 Aug 90 19:01:44 GMT
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Reply-To: John Higdon <john@bovine.ati.com>
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On Aug 26 at 16:05, TELECOM Moderator writes:

> [Moderator's Note: John, are you positive 900's are never translated
> into POTS at the final destination?

In California I'm about 99% sure.

> [Moderator's Note: But if, as you pointed out earlier, the LEC is not
> involved at all, with the 900 guys putting a dish on your roof, etc,
> then *when* does the supervision take place? Who does it?  PAT]

When the IXC provides 900 service directly with, as you point out, a
dish on your roof, it is fundamentally the same as if it came in as
pairs from the LEC. T1 comes in from the short-haul microwave, is sent
to Rockwell or Newbridge channel banks and comes out as tip and ring.
When a call comes in, ring voltage supplied by the channel bank is put
on the line. The answering equipment goes off-hook and the supervision
is sent back towards the IXC's switch which in turn relays it on to
the originating LEC. The only thing left out of the path is an LEC
switch at the terminating end.

The twenty-second chicken exit period begins when the answering
machine goes off-hook. (Some newer equipment can accept the T-span
directly, but the process is the same. Only the channel banks are
eliminated.)


        John Higdon         |   P. O. Box 7648   |   +1 408 723 1395
    john@bovine.ati.com     | San Jose, CA 95150 |       M o o !