one way audio

[bluesea2010]

Hi,

i have third party sip system , when I call  an extension  in cisco cucm  (7941 phone ) , I can't  hear the  caller 

Please help 

Thanks 

[Scott Leport]

Hi,

Typically, these issues are normally IP Routing, NAT or Firewall related, but more info about the setup would need to be known.

What is your integration with the third party SIP system? Is it a SIP trunk configured from CUCM, or is it a third party SIP endpoint which is registered to CUCM?

Can you also clarify is you have the same problems dialling the other way, e.g. from your Cisco 7941 phone to your third party SIP device? Is the same issue apparent with other models of IP phones?

[Nithin Eluvathingal]

This could be a routing issues. From cisco site, ping thrid part site phone and server IP's and vice versa to confirm two way reachability. Make sure that when pining keep the source address  as your VoIPserver/Ip phone subnet IP's .

If  any firewall in between, make sure the firewall configurations will  allow the voip traffic and not to drop.

In third party IPT systems, i have see engineers adding routes. If your third party system need such  route configuration. make sure the system has been configured with required routes towards Cisco.