Cannot transfer calls between two analog pbx extensions via cisco Phone

[frank3333]

Hi All,

Calls from Analog PBX to CUCM Cisco phone cannot transfer back to another analog extension in same PABX (no voice)

Exten 1 (PABX A)--->Cisco Phone (CUCM)--> Extension 2 (PABX A)

Exten 2 can pick the calls originating from exten1 and transfer via Cisco phone but call connected with no voice.

Exten 1 (PABX A)--->Cisco Phone (CUCM) ----OK

Cisco Phone (CUCM)--> Extension 2 (PABX A) ---OK

Exten 1 (PABX A)--->Cisco Phone (CUCM)--> Extension 2 (PABX A) --- No voice between ext1 and ext 2.

Need help to resolve this.

Thanks.

[Divina Vitorino]

Frank, follow some questions

How PBX are connected?

Is there a trunk between then?

Which manufacturer is?

Please check if you have MTP configured.

[frank3333]

Hi Divina,

PBX configured via sip trunk and manufacture is Teltronics.

I didn't checked MTP required on trunk configuration and want to know how to configure MTP.

Thanks.

[Divina Vitorino]

Frank, please follow this guide. 

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/8_5_1/ccmsys/accm-851-cm/a05mtp.html

At Device > Gateway you need to enter your gateway (that is the other PBX) and see if media termination point required option is checked.