I have a Cisco UC520, the SIP trunk is configured and it is up, the incoming calls are transfered to the approperiate extension and users from internal can make a call to outside. when the users call to internal extensions they can talk nice. but when they make a call to external or somebody from outside make a call to the internal the voice from users are not streamed to the other party.
I check the UC access-list and RTP ports are open (UDP from 16384 to 32767) but still can not heared from out side.
totally the call is initiated but the voice just come into the users and when the users speak on the phone the other party can not hear anything.
for more information, the UC device is NAT device for users and it gvies the IP to the clients and phones. it is behind a ADSL router and the internal ip of the ADLS is the default gateway of the UC. so the users will come though the UC and then go to the modem and then to the internet.
any idea about the voice problem please.