Message Waiting MWI Not Working With Cisco 7900 Series Phone

We are currently experiencing issues with the MWI indicator on our SIP enabled 7942 Cisco handsets.

The phones are registering with Asterisk and we can make and receive calls however there is no attempt by the phone to send a SUBSCRIBE with a ‘message-summary’ event package.

We have tried release 8.4 and 9.3 of SIP firmware on the phone and have configured the phone using instructions from other Asterisk forums for the phones configuration.

Could someone confirm if the Cisco 7900 Series phones subscribe to voice mail in the usual way, i.e. a SIP SUBSCRIBE?

Has anyone any suggestions as to why this basic VM feature may not be working?


Did you “Enabled” the Message Waiting in the IP Phone GUI?

Did you set the “Mailbox” field in the IP Phone GUI?

Those parameters do the trick.

I think that in my SPA phones those parameters are inside the Ext1 tab


The phone is a CP 7942G.

By IP phone GUI I assume you are referring to the web interface on the phone. The GUI provided through http is very limited, in fact it’s read only data. You can’t set anything.

On the ‘Device Information’ page it lists the following below (including ‘Message Waiting’):
Phone DN 00249735D6EC
App Load ID jar42sip.8-4-0-79.sbn
Boot Load ID tnp42.8-3-1-21a.bin
Version SIP42.8-4-1S
Hardware Revision 1.0
Serial Number FCH1302BNRP
Model Number CP-7942G
Message Waiting No

We are making some assumptions about what capabilities the phone has. One being that the phone, when configured for SIP, will send out a ‘SUBSCRIBE’ to it’s USECALLMANAGER configured address, for the message waiting service.

Do you know if this is the case? Any experience with this particular Cisco phone?