With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
ccmeEphoneActTable
Cisco Call Manager Express Ephone Active Table
1.3.6.1.4.1.9.9.439.1.2.6
A list of all IP phones currently registered on this device.
Back to CISCO-CCME-MIB MIB page.
IPHost Network monitor allows you to monitor ccmeEphoneActTable on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco wireless switches right now.