With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
ccmPhoneFailures
Cisco Call Manager Phone Failures
1.3.6.1.4.1.9.9.156.1.10.3
The count of the phone initialization or communication failures that are stored in the ccmPhoneFailedTable object.
Back to CISCO-CCM-MIB MIB page.
IPHost Network monitor allows you to monitor ccmPhoneFailures 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.