[asterisk-users] Sporadic One Way Audio

[Brent Davidson]

I'm having an unusual problem at one of my branch offices.  Every now 
and then they will make a call and the person they call is unable to 
hear them, but they are able to hear the person.  The Asterisk server 
has only one ethernet interface and is on the same physical network as 
the 2 snom 300 phones and is connected to the PSTN lines with a  Rhino 
R4FXO-EC card.  Usually hanging up and calling back solves the problem, 
but it is still aggravating to the customer that has been called.  
Normally I'd suspect that something was only passing packets in one 
direction, but there is no firewall between the asterisk server and the 
phones and no iptables or anything like that running on the Asterisk 
server and sifting through sip debug logs to try to find one call out of 
maybe 50 has so far proven fruitless.

Are there any common issues that might cause this?

Thanks,
Brent Davidson