Inline power issue between 3550 switch and 7937 phone

[btedeschi]

Running a 3550 with IOS version c3550-ipbasek9-mz.122-44.SE6. 7937 phone starts to power up and also pops up in sh power inline, but disappears and never registers. Below are some further details from the switch. any help is much appreciated.

This error shows constantly in the 3550 switch log over and over

ILPOWER-3-CONTROLLER_PORT_ERR: Controller port error, Interface Fa0/13: Power given, but link is not up

7937 phone shows up and then disappears after about 10 seconds. phone will not register and this is the only phone having this issue. currently other 7960s and 7940s are registered and working in this location.

SCR-3550-24-01#sh power inline
Available:360(w)  Used:81(w)  Remaining:279(w)

Interface Admin  Oper       Power   Device              Class Max
                            (Watts)                            
--------- ------ ---------- ------- ------------------- ----- ----
Fa0/13    auto   on         15.4    Ieee PD                   15.4 

disappeared

Fa0/13    auto   off        0.0     n/a                 n/a   15.4

Adding this config, "power inline delay shutdown 20 initial 10", to the interface has worked for a 7945 phone when encountered similar issue, but not for 7937.

[Mark Malone · Accepted solution]

I think the 7937 only supports  IEEE 803.af PoE Class 3 and the 3550 does not support this type of POE , only newer model switches do

[Rajan · Accepted solution]

Yes. As Mark mentioned, this switch do not support IEEE 802.3af PoE needed for 7937. You could refer the below thread and the links for reference:

https://supportforums.cisco.com/discussion/10476671/cisco-ip-conference-station-7937-not-working-our-system-help 

More info on POE requirements:

http://www.cisco.com/c/en/us/support/docs/voice-unified-communications/unified-ip-phone-7900-series/97869-poe-requirement-faq.html#qa3

A 3560 or a 3750 switch would do it.

HTH,

Rajan

Please rate useful posts