On Thu, 28 Oct 2004, Steve Underwood wrote: > Stephen David wrote: > >i don't have a specific bug in mind, i was just wondering WHY call progress doesn't > >work so well -- in particular, on analog lines. ie. is it a hardware or software > >problem (or both). with more info, i'd like to help to work out the kinks, for > >myself and everyone. :) > > > Back in the days of Stowger exchanges you knew when the called party > answered, by a reversal of the DC voltage on your analogue line. With > digital exchanges that stopped, and no solid feedback is given to the > caller on ordinary analogue lines. You have to infer that someone has > answered, and the reliability of that can be poor. Digital lines, like > ISDNand SS7, and protocols like MFC/R2 tell you positively that someone > has answered.
At least in Sweden pots interfaces in the pstn all have answer and disconnect supervision through polarity reversals. > If you had good results with Dialogic it was merely luck. Because they > have to infer the phone has been answered, their detection only works if > the calls follow their model of how someone answers the phone. Depending > on your circumstances, and the nature of the calls you make, it can be > hopelessly unreliable. It could be that it handles answer supervision and that his pots line has tbat option as well. Peter _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users