[cisco-voip] PSTN rings once, router answers, then silence...

[Robert]

On Tue, 2009-01-27 at 18:04 +1030, Tom Storey wrote:

> Sometimes when a call comes in via the PSTN the caller will hear a  
> single brief ring, being the PSTN ringing, they will then hear the  
> 1760 pick up due to the ringing stopping, but then there will be  
> silence and the phone attached to the FXS port will not ring.

I have a few 2811's with FXO cards. They will exhibit a similar symptom
on occasion, wherein callers hear one ring then silence, but the calls
seems to have gone nowhere.

I will generally find that the gateway is not registered with my
CallManager. The simplest fix has been to log on to the 2811's console,
enter config, issue a 'no mgcp' followed by 'mgcp'. This forces it to
register.

Luckily, I can usually cite connection problems preceding the onset of
this symptom for that location, generally involving a flapping circuit.

Robert