Hi Richard. I got this right off the hardware installation guide for the 2520. Page 1-4 The 10/100 PoE ports on the Cisco CGS-2520-16S-8PC switches provide PoE support for devices that are compliant with IEEE 802.3af. The Cisco prestandard PoE is also supported for Cisco IP Phones and Cisco Aironet Access Points. The PoE ports on the switch deliver up to 15.4 W of PoE. Any four of the eight ports are designated as high priority PoE ports, while other four ports are designated as low priority PoE ports. When both the power-supply modules are installed, the system has enough power to support all the eight ports as PoE ports. In case one of the power-supply module fails, the power to the low priority PoE ports is dropped, while power to the high priority PoE ports remains uninterrupted. Maybe they will get is POE+ in later revisions.
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Thanks for the replies! From the switch spec sheet in table 5 "Power Specifications" under the conditions: "100% Throughput (With Maximum Possible PoE Loads)", the measured power consumption for the switch itself is: 502 watts Under this condition: Switch itself + 24 ports of EPoE power sourcing 502 watts + (24 * 20 watts) 502 watts + 480 watts = 982 watts 982 watts > 750 watt rating of the power supply So what happens under these conditions? Even for this load condition for normal PoE (15.5 watts per port) from the spec sheet Table 5 "Power Specifications" again: Measured Power Consumption is: "502 Switch and 372 PoE Power" 372 = 15.5 * 24 So even under this condition, power consumption is (502+372) = 874 watts, which appears to be above the 750 watts available.
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