With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
ccmPhoneEntry
Cisco Call Manager Phone Entry
1.3.6.1.4.1.9.9.156.1.2.1.1
An entry (conceptual row) in the phone Table, containing information about a particular phone device.
Back to CISCO-CCM-MIB MIB page.
IPHost Network monitor allows you to monitor ccmPhoneEntry on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.