With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
isdnEndpointIndex
isdn Endpoint Index
1.3.6.1.2.1.10.20.1.4.2.1.1
The index value which uniquely identifies an entry in the isdnEndpointTable.
Back to ISDN-MIB MIB page.
IPHost Network monitor allows you to monitor isdnEndpointIndex 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.