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From: patrick@chinet.chi.il.us (Patrick A. Townson)
Newsgroups: comp.dcom.modems
Subject: Re: can a modem respond to CALL WAITING ??
Keywords: modem call waiting
Message-ID: <1991Jun02.205244.24464@chinet.chi.il.us>
Date: 2 Jun 91 20:52:44 GMT
References: <14380@exodus.Eng.Sun.COM>
Organization: Chinet - Chicago Public Access UNIX
Lines: 42


In article <14380@exodus.Eng.Sun.COM> hpchen@celestial.Eng.Sun.COM
(Huei-Ping Chen) writes:

>my friends have been complaining about my home phone very hard to get
>through, since I have been dailing-up from home to my work station at work 
>a lot.

>I know there is a phone service "CALL WAITING", while you are on the phone,
>if someone is trying to get through, it will give you a beep tone.

>my question is: is there a way while the modem is using the phone line, 
>the modem can detect the CALL-WATING signal, and warns you somebody is trying
>to call you??

Sure there is.  The modem garbages your screen just before losing carrier
and hanging up ... then your phone rings and the new caller is on the
line.  :)   I know that is not the answer you wanted!

You cannot put a modem call 'on hold' to take a call-waiting on the same
line. A human ear knows what it is listening to; all the modem knows is it
does not hear carrier from the other end any longer (while on hold).

If your modem has a register you can set to say how long the modem should
wait with loss of carrier before hanging up, you can set this to a very
high value, and instead of sending garbage to your screen *and*
disconnecting when it hears a call waiting tone, it will merely send the
garbage and you have to take this as a hint to either gracefully save your
work and log out (then take the new call) or ignore the call-waiting and
continue to get a couple more rounds of garbage before the caller hangs
up. 

Call waiting and modems make a very bad pair. NEVER get call waiting on a
line you ordinarily use for modems.  Better to get two physical lines from
the phone company instead for only a little more money.


PAT
-- 
Patrick Townson 
  patrick@chinet.chi.il.us / ptownson@eecs.nwu.edu / US Mail: 60690-1570 
  FIDO: 115/743 / AT&T Mail: 529-6378 (!ptownson) /  MCI Mail: 222-4956