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

[Tom Storey]

Hi all.

I have a 1760 with a VIC-2FXO and VIC-2FXS. I have connected the phone  
to FXS port 3/0, and the PSTN to FXO 2/0, and Im running into a  
strange issue.

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.

Every other time when a call comes in there will be a single brief  
ring and the 1760 will answer and produce its own ringing tone, and  
the phone attached to the FXS port will ring.

There doesnt appear to be any particular sequence of events to cause  
it to happen that I have been able to work out. Its just completely  
random.

Can anyone suggest any settings that I can adjust (Im trying "ring  
number 2" at the moment to see how that goes) that might cease this  
behaviour, or suggest any debug commands that I can run to try and  
capture what is going on?

Unfortunately its just a residential line, so there arent that many  
calls made in so it might take a while before it happens again. But  
thats all part of the fun right? ;-)

Cheers,
Tom