PoE configuration for Cisco 7821

[RFC_2549]

Hello, 

I have 2 Cisco 7821 phones connected to a SG250-08 8-Port Gigabit Smart Switch with PoE+ ports, the phones are not powering up and I don't know why. Can You please help me to find out what is going on?

The poe is configured in this way:

PD Port ID: GE1

PD Por 1 Negotiation mode: Force 802.3AF

PD Port 1 Status:Connected

PD Port 1 Type:802.3 AF

PD Port 1 Budget:15.4 W

The port is "down" but here the output of "sh powerded-devices"

SG250-08#sh powered-device

Port PD Power PSE Standard Power
Standard Requested(W) (link partner) Available(W)
---------- -------- ---------------- -------------- -----------------------
gi1 802.3AT 15.400 (forced) 802.3AF 15.400

If I switch to "auto" settings, then the result of the command will be the following:

SG250-08#sh powered-device

Port PD Power PSE Standard Power
Standard Requested(W) (link partner) Available(W)
---------- -------- ---------------- -------------- -----------------------
gi1 802.3AT N/A N/A N/A

Thank You for the help

[Maren Mahoney]

Two seemingly dumb, but important questions:
First: Are your cables Cat5E cables and are they fully wired (all four pair) and not longer than 75 meters?  (10/100 802.3af Mode B requires all four pairs.)

Second: Have you swapped out the Ethernet cables themselves? Slight damage can cause PoE to not work.

Also check out this doc, looking at the section "Debug and PoE" (hopefully the same or similar commands will work on your 250-08) to see what is happening with negotiation:

Troubleshooting Power over Ethernet (PoE) 

HTH

Maren

[RFC_2549]

I tried with CAT 5 and CAT 6 patch cable, and the ones that was in the box (no CAT indicated)...I swapped them thank You for the guide!

[RFC_2549]

Solved: this specific version of 250-08 switch is not PoE