On Thu, Feb 28, 2008 at 08:47:37AM -0600, James Texter III wrote: > On Feb 27, 2008, at 2:55 PM, Tim Nelson wrote: > > Hello! I've run into a problem where a user is making an outbound > > call at the same time that an inbound call is being made on the same > > analog line. It appears that as the zap channel is opened for the > > outbound call, it is simply answering the inbound call. Obviously, > > both parties involved in the calling get a bit confused. Previously, > > it happened only on an occasional basis. However, as this > > installation gets more and more use, we are finding it happens more > > often. How can this situation be prevented? Shouldn't zaptel see an > > incoming call and simply choose another trunk? We are running > > Asterisk 1.2.12.1 and Zaptel 1.2.22.1. Any ideas?!? > > In the telephony world, this is called glare, it's most prevalent on > Analog (though you can have the same thing happen with robbed-bit > T1). There really isn't much you can do to prevent it, only minimize > it. You need to have your inbound and outbound starting at opposite > ends. If your incoming calls are coming top down, then you need to > use G<your group number> in your Dial app so that outbound calls go > bottom up, or vice versa.
And, to expand a bit, this comes from the fact that on analog (and I guess RBT-1, though I hadn't realized it happened there), there is not a 3-way handshake to open the channel; each end can open it unilaterally. This leads to a race condition, and thus, 'glare'. The *reliable* way to fix this is to go to PRI, if you can a) get it, b) afford it, c) terminate it, and d) profit!! Oh, sorry; that's Slashdot. Never mind. :-) Cheers, -- jra -- Jay R. Ashworth Baylink [EMAIL PROTECTED] Designer The Things I Think RFC 2100 Ashworth & Associates http://baylink.pitas.com '87 e24 St Petersburg FL USA http://photo.imageinc.us +1 727 647 1274 Those who cast the vote decide nothing. Those who count the vote decide everything. -- (Joseph Stalin) _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users