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- Newsgroups: comp.dcom.modems
- Path: sparky!uunet!math.fu-berlin.de!fub!geminix.in-berlin.de!gemini
- From: gemini@geminix.in-berlin.de (Uwe Doering)
- Subject: Re: GVC 9600 / T2500 / MNP problem fixed (sort of)
- References: <1992Jul12.050707.10241@imax.imax.com> <1992Jul21.234857.13973@imax.imax.com>
- Organization: Private UNIX Site
- Date: Thu, 23 Jul 1992 07:46:31 GMT
- Message-ID: <Z6C5HJB@geminix.in-berlin.de>
- Lines: 23
-
- dave@imax.imax.com (Dave Martindale) writes:
-
- >However, a new problem reared its head. The old T2500, when S92=0,
- >answers an incoming call with PEP tones, then V.25 answer tone,
- >then V.32 carrier, and then slower speeds. The GVC was happy with this,
- >and connected in V.32 mode. The new T2500 always answers with a burst
- >of V.25 answer tone *first*, before the PEP tones. (This is probably
- >to help it deal with echo suppressors on some phone lines). In effect,
- >S92=0 now produces exactly the same result as S92=2 always did.
- >
- >The GVC, it seems, is just not willing to recognize V.25, PEP tones,
- >a bit more V.25, and then V.32 carrier as a valid V.32 answer sequence,
- >and ends up connecting in V.22bis (2400 bps) mode instead.
-
- Set S120=16. This disables the echo canceller disable tone (V.25)
- preceding the PEP tones in modems with 7.xx ROM releases. This register
- is unfortunately not documented in the regular modem manuals.
-
- Uwe
- --
- Uwe Doering | INET : gemini@geminix.in-berlin.de
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