With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cmTotalCallDuration
cm Total Call Duration
1.3.6.1.4.1.9.9.47.1.3.3.1.17
A counter that indicates total call duration on the modem. This includes the duration of all previous calls.
Back to CISCO-MODEM-MGMT-MIB MIB page.
IPHost Network monitor allows you to monitor cmTotalCallDuration on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco mobile switches right now.