CM to PSTN - One Way Audio

[RX3]

I have a Cisco 2651 router with a NM-1V w/ a VIC-2FXO card. The router is configured and registered with the CallManager as a MGCP Gateway.

I am able to make and receive calls, but there is only one way audio. I am able to hear the party on the other end, but they can not hear me. Even if I make a call and place it on hold, the party on the other end of the line will just hear silence, and no music. I've tried calling several phones with no luck.

Here is the configuration from the router:

---------------------------------------
!
!
voice-port 1/0/0
no echo-cancel enable
timing hookflash-out 500
!
voice-port 1/0/1
no echo-cancel enable
timing hookflash-out 500
!
ccm-manager mgcp
ccm-manager music-on-hold
ccm-manager config server 10.128.0.5
ccm-manager config
!
mgcp
mgcp call-agent 10.128.0.5 2427 service-type mgcp version 0.1
mgcp dtmf-relay voip codec all mode out-of-band
mgcp rtp unreachable timeout 1000 action notify
mgcp modem passthrough voip mode nse
mgcp package-capability rtp-package
no mgcp package-capability res-package
mgcp package-capability sst-package
no mgcp package-capability fxr-package
mgcp package-capability pre-package
no mgcp timer receive-rtcp
mgcp sdp simple
mgcp fax t38 inhibit
mgcp rtp payload-type g726r16 static
!
mgcp profile default
!
!
!
dial-peer voice 999100 pots
service mgcpapp
port 1/0/0
!
dial-peer voice 999101 pots
service mgcpapp
port 1/0/1
!
---------------------------------------

I've tried everything, echo cancelation off, echo cancelation on, still the same thing, the called party can not hear me.

I also tried setting the attendant DN to the VM pilot, the system answers and then there is dead-air, so there is no audio coming through from Unity either.

Everything works great internally.

 

[pndscm]

Can you ping the phones you are calling from the router?? You could have a routing problem.

 

[MG2005]

almost always an IP routing issue

basic help:

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a008009484b.shtml

i have more ta the offic eon this tomorrow i can supply

my issue once was the no ip routing command is set by default on most routers out of the box

 

[Ratmtattat]

If possible, try adding the following command in the global config:

(Router)#voice rtp send-recv

Typically by default Cisco sets it up so that only the backwards stream cuts through when the call is made, which tends to lead to the situation you're talking about. Hopefully this will allow full connections both ways when initiating a call.

 

[RX3]

I figured it out. It was a routing issue with a loopback interface on an MSFC on a switch that was on the way to the VG.