[Asterisk-Dev] User picks up phone, hears another call, not dialtone (fwd)

[Steve Creel]

I sent this to the users list yesterday, but on second thought, it
probably belongs here.

---------- Forwarded message ----------
Date: Thu, 29 Apr 2004 12:25:20 -0400 (EDT)
From: Steve Creel <screel at turbs.com>
To: asterisk-users at lists.digium.com
Subject: User picks up phone, hears another call, not dialtone

First of all - Many, many thanks to Mark for his troubleshooting and fix
of bug 1320 (FXO_KS signalled Zap Channels on Adtran 750 Channel Bank
Stuck in Rsrvd State).


I have heard complaints that once every couple weeks, when a user picks up
their analog phone (t1 span off of a TE410P into an Adtran 750 with 6 FXS
cards), they don't get dialtone, but instead, hear another conversation.
I'm under the impression that they can only hear and not speak into that
conference.

System information:
This has happened with zaptel and asterisk from November 2003, as well as
after an upgrade in mid April 2004 (most recent occurance was with
asterisk CVS from March 26, Zaptel from April 24th)
System is a dual Xeon 2.4GHz, 1GB RAM
Load avg: 0.04, 0.04, 0.00
Single TE410P with a channelized T1 from clec providing timing, 2
channelized T1s out to two Adtran 750s.
Handsets are AT&T/Lucent/Avaya 2554 sets

The first time I heard about this, I didn't believe it (one morning three
people said it happened).  Since it has returned several times since, I'm
forced to assume it is actually happening.  I highly doubt it is a problem
with the house wire.

Is it possible this is actually happening?  What could possibly cause this
behaviour?

Many thanks.
Steve