Re: Linux support for voice modems?

From: John-Paul Stewart (jpstewart_at_binaryfoundry.ca)
Date: 05/04/05 

Date: Wed, 04 May 2005 10:51:44 -0400

Haines Brown wrote:
> Thanks for the follow up. Basically, my earlier impressions are
> confirmed - FAX operates at a normal frequency, and so must reside on
> the phone side of the output from a DSL filter.
>
> This implies that the old problem of signal discrimination
> remains. The conventional options seem to be a) a dedicated FAX line,
> b) a distinctive ring to differentiate a voice call from an incoming
> FAX.
>
> Why I have a difficulty with this is because it seems to me that years
> ago I had a card (German? "Catseye"?) that could discriminate between an
> incoming voice call and an incoming FAX. It sent FAXes to the printer
> and voice messages to ring the phone. If I recall corretly, the phone
> never rang unless it was a voice call. Am I imagining things, having a
> senior moment?

I've never seen it done in hardware, but that doesn't mean it can't be.
  Software, sure. But that means the computer has to answer *all*
incoming calls and decide what to do. The vgetty docs mention that
briefly, saying that if a non-voice call is detected, vgetty can be
configured to spawn mgetty to handle a data call.

There are DTMF tones sent over the line to distinguish between voice and
data calls, so using those you could have the computer (hardware or
software) respond differently to voice/fax calls, but that's *after*
answering them.

[snip]
> I use fax too little to make a dedicated line worthwhile, I would
> like to send/receive FAXes from the computer, and I would not want my
> phone to ring if it is only a FAX coming in. Am I dreaming?

That might be a bit of dream. Have you looked at the full VOCP system
(built atop vgetty and mgetty)?

http://www.vocpsystem.com/

It won't quite do what you want, but it can come close. You can either
have it answer all calls (voice and fax) and take voicemail or receive
the fax. Or could you could have it answer no calls, and manually
transfer incoming fax calls to the software. There are lots of possible
scenarios that you could configure, but not quite what you're after.

But to distinguish before answering (and hence not ring the phone for a
fax) isn't possible without another line or distinctive ring, AFAIK.

Relevant Pages

  • Re: Linux support for voice modems?
    ... incoming voice call and an incoming FAX. ... and voice messages to ring the phone. ... is there an analog modem card smart enough to ...
    (comp.os.linux.hardware)
  • Re: Phone/Fax separation
    ... incoming) and for FAXing, out going and incoming. ... To automatically separate the voice calls from the FAX calls I have a ... The use of a CommShare switch has one fault, ... it continues to ring until the caller hangs up. ...
    (microsoft.public.windowsxp.general)
  • Re: Linux support for voice modems?
    ... > a fax) isn't possible without another line or distinctive ring, ... > incoming calls and decide what to do. ... > briefly, saying that if a non-voice call is detected, vgetty can be ... I infer that while vgetty might discriminate between voice and ...
    (comp.os.linux.hardware)
  • Re: Linux support for voice modems?
    ... >>a fax) isn't possible without another line or distinctive ring, ... >>incoming calls and decide what to do. ... I infer that while vgetty might discriminate between voice and ...
    (comp.os.linux.hardware)
  • ROH Cycle 1 Siegfried - 7 October
    ... I survived my least favourite patr of the Ring! ... he nearly forgets his sword when he runs off to find Brunnhilde. ... Sir John Tomlinson started well (underpowered high notes aside) and ... think she's fab and love her voice in general. ...
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