With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cpeExtPdStatsTotalDevices
cpe Ext Pd Stats Total Devices
1.3.6.1.4.1.9.9.402.1.4.1
This object indicates the total number of the powered devices with any power classifications in the system. Classification is a way to tag different terminals on the Power over LAN network according to their power consumption. Devices such as IP telephones, WLAN access points and others, will be classified according to their power requirements.
Back to CISCO-POWER-ETHERNET-EXT-MIB MIB page.
IPHost Network monitor allows you to monitor cpeExtPdStatsTotalDevices on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco switches right now.