With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
ciscoCallHistoryCallDisconnectTime
cisco Call History Call Disconnect Time
1.3.6.1.4.1.9.9.27.1.1.3.1.10
The value of sysUpTime when the call got disconnected last.
Back to CISCO-CALL-HISTORY-MIB MIB page.
IPHost Network monitor allows you to monitor ciscoCallHistoryCallDisconnectTime on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco routers right now.