random one way audio - inbound call only

[nguyentienthanh]

Hi Expert and Every Member,

My UC System include 2 CUCM 6.1 , 1 Unity Connection 2.0, 1 Voice Gateway 3825 with 12 FXO, 1 Operator with IP Phone 7962 ( 2 Expansion Module 7914). We can do outbound call very well. Unfortunately, when customer from PSTN do inbound call to my Operator, they sometimes get one way audio call that means customer can hear operator 's voice but Operator can not hear customer voice. This call is happen very intermittent about 10 inbound call success i get 1 one way audio inbound call. I try to do many ways to solve as below but it is still happen:

- Check IP Routing, i can ping everything.

- Add command : h323-gateway voip interface
                           h323-gateway voip bind srcaddr

                           voice rtp send-recv

- Set CUCM 's eth0 to auto, auto (1000Mbps)

- All IP Phone, VoiceGateway register on primary CUCM

My boss is not happy about that. Please give me your recommends to solve it quickly.

Thanks and best regards,

ThanhNT

P/s: i send to you my Voice Gateway 's configuration

[dmotloch]

Let me make sure I understand.

You have 12 FXO ports on one ISR Router, H323 to your Call Manager cluster.... there is a DID or mulit-DID's pointing at the 12 FXO's from the PSTN.  Users calling in, 10% are one way audio....??

Ok -- so one way what way?  The PSTN caller can hear you but you (IP Phone) can't hear the caller or the other way?

Is it always the same phone that gets the one-way audio?

Can you duplicate it by calling your inbound number 10 times from your cell phone, do you get one-way?

Give more details please.

Derek.

[nguyentienthanh]

Hi Dereck and everybody,

I am sorry for late information to you coz i went to holiday with my family.

dmotloch wrote:
Let me make sure I understand.
You have 12 FXO ports on one ISR Router, H323 to your Call Manager cluster.... there is a DID or mulit-DID's pointing at the 12 FXO's from the PSTN.  Users calling in, 10% are one way audio....??

Yes they are, but the customer call from PSTN will forward to Auto-attendant of Cisco Unity Connection. Then customer dial 0 to reach Operator. When they connected to Operator one way audio happen but very randomly.

Ok -- so one way what way?  The PSTN caller can hear you but you (IP Phone) can't hear the caller or the other way?
Is it always the same phone that gets the one-way audio?

Yes it is, correct

Can you duplicate it by calling your inbound number 10 times from your cell phone, do you get one-way?

Yes, correct

See your advise soon !

Regards,

ThanhNT

[Mohd. Hidzwan Tamrin]

Hi,

I faced kinda similar problem like this. I know it has been 5 years since, but if anyone managed to get a solution do share it here. would appreciate it so much

thanks,

Hidzwan

[denz_cruel]

Any update on this? Did you manage to fix this issue? I am having the same issue for two sites that Dial 0 to the operator having one-way audio. The operator cannot hear anything.

[Mohd Afadzal Mohamadin]

Maybe you can check with your transcoder on VGW. PSTN codec always g.711 but you iptel infra always g.729. Maybe you need to create more transcoder session on VGW.