With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
csbHistoryStatsSrtpNonIwCalls
Cisco Session Border History Stats Srtp Non Iw Calls
1.3.6.1.4.1.9.9.657.1.4.1.37
This object indicates the number of active calls through this adjacency or account that have one or more media channels that use SRTP but no media channels that provide interworking between RTP and SRTP during this interval.
Back to CISCO-SESS-BORDER-CTRLR-CALL-STATS-MIB MIB page.
IPHost Network monitor allows you to monitor csbHistoryStatsSrtpNonIwCalls 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.