With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
isdnSigStatsChargedUnits
isdn Sig Stats Charged Units
1.3.6.1.2.1.10.20.1.3.3.1.5
The number of charging units on this interface since system startup. Only the charging units applying to the local interface, i.e. for originated calls or for calls with 'Reverse charging' being active, are counted here.
Back to ISDN-MIB MIB page.
IPHost Network monitor allows you to monitor isdnSigStatsChargedUnits 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.