[Asterisk-Users] Re: Strange Problem

Rich Adamson radamson at routers.com
Fri Mar 12 13:31:05 MST 2004

> > I am experiencing a strange problem and wanted to know if someone has 
> > faced any similar issues or could provide me with a way to counter this 
> > problem. I am in the process of experimenting with asterisk and trying 
> > to setup a basic functional system. I have one TDM400P (single port) and 
> > one X100P. I am using one analog phone connected to the TDM400P and I 
> > also have a couple of Xlite SIP phones configured. I can make calls out 
> > to the PSTN and I can also receive calls.
> > 
> > The problem happens when someone from the outside (PSTN) calls the 
> > Asterisk box. I have asterisk configured to forward the call to Zap/2 
> > (analog phone). Zap/2 rings and I can talk to the person on the other 
> > end but if I hang up first then the other end does not see as the call 
> > being hung up. Asterisk CLI shows that Zap/1-1 (FXO) hungup but for some 
> > reason the other end thinks that the call is still up and does not 
> > disconnect unless the person hangs up himself. The confusing part is 
> > that if I initiate the call then this problem does not happen.
> > 
> > Can someone tell me what is happening and how to resolve this issue?
> >
> On analog lines, the central ofice switch will signal that the remote 
> end hung up the call, if I recall correctly, either by dropping loop 
> current or using a brief polarity reversal. There may be other means as 
> well.  You need to make sure that you are using the correct settings to 
> sense this properly.
> The reason you don't see this when you place the call is that, 
> obviously, your end has no trouble determining when you have hung up, 
> regardless of setting that affect the detection of the remote end 
> hanging up.

Just for the record, there seems to be an issue brewing in the sip 
channel relative to disconnects. 
  C7960 -> * -> sip gateway -> pstn
When the C7960 hangs up on a call, we see the 7960 issue a BYE to *,
but * does NOT always send a BYE to the gateway. That's watching closely
with a packet sniffer, all on the same wire, likely loaded SOHO asterisk.


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