Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request
From: Vance Shipley <vances@xenitec.on.ca>
Newsgroups: comp.dcom.telecom
Subject: Re: Call Waiting Question
Message-ID: <3527@accuvax.nwu.edu>
Date: 4 Feb 90 21:27:39 GMT
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Reply-To: vances@xenitec.UUCP (Vance Shipley)
Organization: SwitchView - Linton Technology
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X-Telecom-Digest: Volume 10, Issue 76, message 3 of 13


In article <3473@accuvax.nwu.edu> tronix@.UUCP (David Daniel) writes:

[discussion of call waiting on modem lines...]

>Change the value of register S9 Carrier Detect Time from the default
>of 7 (.7 seconds) to 15.

>This increases the time between loss of carrier and modem disconnect.
>Of course the host modem will need to be on an eqivalent setting as
>well.  

Actually, most offices do not pass the call waiting indication tone to
the far end.  Some will blank out the tone (to prevent the wrong party
from thinking they have a call waiting). In this case the far modem
will need to be as forgiving ablout carrier loss.  Others (mine) do
not give any indication at all, the modem would continue to send
carrier.  In any case it would be dependent on your CO so it will work
the same way for all calls.


Vance Shipley
SwitchView - Linton Technology                       vances@xenitec.UUCP


[Moderator's Note: In a digital CO, the other end hears *nothing at all*.
The only way you know the other person has a call waiting (as opposed
to the click you hear while the other person hears tone in older systems)
is if they are talking, you hear their voice drop out for a half second.
If you are talking at that instant, you detect nothing.  PT]