Re: [hylafax-users] [hylafax-devel] Re: Re: Distinctive ring & cid

["Jay R. Ashworth" <jra@baylink.com>]

On Thu, Jun 21, 2001 at 06:21:17PM -0600, Lee Howard wrote:
> At 08:13 PM 6/21/01 -0400, Jay R. Ashworth wrote:
> >On Thu, Jun 21, 2001 at 08:03:12PM -0400, Jay R. Ashworth wrote:
> >> Fact: TR-TSY-000030 *requires* that that the CNID burst be sent
> >> *between* the first and second rings sent to the station.
> >> 
> >> It can't ever be sent before the first ring, because most boxes sleep
> >> until they hear ring signal.
> >> 
> >> It can't be sent later because people won't wait.
> >
> >And I apologize; I meant to add that it can't be sent *during* the ring
> >because it would be way too expensive to design circuitry to extract
> >the 1V P-P 201 modem signal off the edge of the 90VAC ring signal.
> 
> The CID man page update reads the way it does rather than specifying that
> CNID data comes between rings 1 and 2 because CNID delivery timing is
> different on ISDN, or so I gather.  But, we're talking analog here, so...

Um, "oops".  TSY-30 applies to analog loop-start circuits only.  You're
right, on BRI you get it first.  But I *think* the modem firmware, by
default, delays the presentation anyway for compatibility... though I'd
be happy to be proven wrong.

Cheers,
- jra
-- 
Jay R. Ashworth                                                jra@baylink.com
Member of the Technical Staff     Baylink
The Suncoast Freenet         The Things I Think
Tampa Bay, Florida        http://baylink.pitas.com             +1 727 804 5015

   OS X: Because making Unix user-friendly was easier than debugging Windows


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