Third-party SIP Phone onhook/offhook status

[Tori_Ok.]

Could anyone please help with some direction on where I can find more details about monitoring/transmitting onhook/offhook status for third-party SIP phones registered to a CUCM cluster. I have CUCM v.11.5 and would like to perform an integration where an external (non-CUCM) server monitors and uses the phone status information as a trigger for some other action.

From much older posts, it appears this may be possible through JTAPI, but I'm not sure if anyone has worked on something similar with more recent Cisco Collaboration versions /tools.

Any help appreciated.

[dstaudt · Accepted solution]

• RFC standard SIP (i.e. what you would find in most generic 3rd party SIP phones) does not include a facility for offhook status at all
• Cisco SIP phones implement proprietary SIP extensions to make offhook status work (along with a plethora of other enterprise-y features)
• A handful of 3rd party SIP phones have received licensing to implement some Cisco SIP extensions, so its possible they might implement the offhook extension
• Applications can monitor real-time phone activity (including off/onhook events) remotely via the CUCM CTI interfaces (TAPI or JTAPI)
• However, 3rd party SIP devices (even those licensed to Cisco proprietary extensions) are not permitted to implement the SIP extensions needed to make CTI work with CUCM

So, it could be possible to monitor SIP packets over the wire from (a limited set of licensed SIP extensions phones) to see the offhook message, however mostly you will find its not feasible to do what you're asking for...

[Tori_Ok.]

Thanks so much for responding. Based on the information you have provided, I think I should rule out the offhook/onhook status.

Would you also happen to know if I can monitor a basic standard SIP message (e.g. INVITE for call setup) sent from the 3rd party phone to CUCM. Since CTI is also not supported for 3rd party phones, this would have to be through some other means. At a minimum, I need to know when a specific phone makes a call.

[dstaudt]

Unfortunately UCM CTI is the only mechanism for apps to monitor devices/calls in real time

I think your only option would be to sniff SIP packets off the wire and interpret them - not really feasible for a system-wide solution.

Depending on the 3rd party phone, it may have its own facilities for monitoring calls, either via SIP primitives, SIP-SIMPLE or some kind of proprietary API; however you would have to deal with each make/model of phone separately, I fear...