Customer calls transferred internally to supervisor - one way voice

Unanswered Question
Apr 29th, 2012
User Badges:

Hi All,

We have the Hosted IPCC call center

IPCC 8.5(2)

CVP 8.5

UCM 8.5

It is SIP based configuration, We have a complaint from supervisor that sometimes agent receive the calls and transfrer to supervisor but supervisor could not able to listen the customer voice (one way voice), so customer getting angry and disconnected the call.

MTP is not been enabled on the SIP Trunk.

So please suggest something.

with Regards,


  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
anchoudh Sun, 04/29/2012 - 02:46
User Badges:
  • Red, 2250 points or more

Hi Manivannan,

Please refer the below CVP release notes,

There are couple of times one-way audio thing has been mentioned. Please check if it helps.

-Unified CVP requires the SIP trunk to be set for RFC2833 due to one-way audio issues found in testing.

-TelePresence caller dials into Unified CVP, receives audio-only IVR and/or queuing treatment, and then is transferred to an agent on an audio-only IP Phone. MTP must be enabled on the SIP trunk or else one-way audio is encountered.

Hope it helps,


Please rate the helpful posts by clicking on the stars below the right answers !!

How exactly is this transfer to the supervisor being done. Is the agent using CTIOS/CAD to start a consultative transfer to the number of the supervisor, and then completing the transfer? Or do you have a more complicated method of calling an internal Route Point (on CUCM) and running an ICM script to queue to a skill group of supervisors?

In almost every common case, enabling MTPs is not the right solution. In early versions of CVP, MTPs were needed for warm transfers but that was fixed.



manivannan.para... Mon, 04/30/2012 - 02:06
User Badges:

Agent is receiving the customer call and speaking

Agent is making another call to supervisor (through the ip phone to supervisor exension)

Agent is talking to supervisor

And Agent transfering the customer call to supervisor,

Now supervisor could not able to listen customer

anchoudh Mon, 04/30/2012 - 20:50
User Badges:
  • Red, 2250 points or more

Hi Manivannan,

Any luck after the above change?



sandeep pokhriyal Wed, 05/02/2012 - 14:26
User Badges:

We have tried enabling RFC 2833 but the problem still persists. in the meanwhile i have found this document on Cisco site.

i have put the command

gateway(config)# conf t
gateway(config)#no voice-fastpath enable.

hope it will resolve the issue.



manivannan.para... Sat, 05/12/2012 - 23:41
User Badges:

We have upgraded the IOS based on the Cisco TAC, problem is solved. Thanks for all

agtmcgarry Wed, 08/15/2012 - 02:23
User Badges:

Hi Manivannan

I am seeing the same problem with the same versions of UCCE,CVP,CUCM.

What version of IOS resolved your problem.

We tried the ET for this bug, CSCty88790, last night but no joy.



agtmcgarry Wed, 08/15/2012 - 02:43
User Badges:

Hi Sandeep,

Thanks for the reply

I Tried




we have AS5350XM, 3800 and 2800 gateways all with the same problem.

However call flow is a bit different.

Instead of transferring to the supervisor phone directly the agent uses transfer init to an DN that routes up the SIP trunk

to CVP gets IVR treatment then connects to another agent. When the agent answers the agent can hear the caller but the caller cannot hear the agent.

Single step transfers work fine



This Discussion