[Asterisk-Users] DTMF intermittently stops working

[Pedro]

Every so often I get a report from a customer that DTMF stops working
while checking voicemail.  The customer has to hang up and check for
messages again.  I have actually had this happen to me twice in the
past 6 months so I know it does happen, just not very often.

So far, the only incidents have been with Cisco 7960's.  I was just
wondering if anyone had noticed this behavior in their environment. 
We are using ulaw and rfc2833 with the following configuration
(Asterisk CVS-v1-0-11/12/04):

SIP Provider (SIP)----(SIP) Asterisk Gateway (IAX)----(IAX) Customer
Asterisk Server (SIP)----(SIP) Cisco 7960


Any thoughts are appreciated.

Thank You,
Pedro
TRACI.net