External Line (E1/T1) Monitoring with SIP phones

[CSCO11914161]

Hello all.

We purchased voice bundle 2951 and CUCM 8.5 and now I have some troubles with external line monitoring on my SIP phones. all phones are registered on CUCM sucsessfully, but i have no idea how to make the phone button (BLF) to signal when the external line is busy. for example, when the calling number such as 1-XXX-XXX-XXXX goes through translation-pattern from PSTN (E1 line) it performs internal number (1001) then. But when the person tries to make a call transfer to another external number, he cant see if the line is still busy or a conversation is done already. Is it possible with SIP phones (9971) to know if the external line (E1/T1) is busy?

thank you in advance.

[Jing Hua]

Hi Andrey,

I don't believe CUCM can monitor PSTN numbers by using BLF unless service provider can provide PSTN number's presence information via SIP.

below is more detailed information regarding how CUCM native presence works:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/6_0_1/ccmfeat/fsprsnc.html

Cisco Unified Communications Manager handles all presence requests for  Cisco Unified Communications Manager users, whether inside or outside  the cluster.

For a Cisco Unified Communications Manager watcher that sends a presence  request through the phone, Cisco Unified Communications Manager  responds with the presence status directly if the phone and presence  entity are colocated.

If the device exists outside of the cluster, Cisco Unified  Communications Manager queries the external device through the SIP  trunk. If the watcher has permission to monitor the external device, the  SIP trunk sends the presence request to the external device and returns  presence status to the watcher.