HP 2620-48-POE and Cisco 7970 phone

[James Thomsen]

I have a new HP ProCurve 2620-48-POE switch and I'm trying to connect some of our Cisco 7970 (without the G) phones to it.  I got the phones to work fine, I can place and receive calls, but the phone doesn't negotiate the POE properly.  It ends up in low power mode.  So far the only effect of this is that the backlight is limited and makes the phones a bit too dark to read.  I've tried setting the POE manually, but that didn't make a difference.

Does anyone have any ideas on how to get the Cisco phones and the HP switch to negotiate POE correctly?

[Vince-Whirlwind]

If the 7970 is pre-standard (the 7970G is 802.3af, dunno about the non-G one), you could try the following command on the switch:

power-over-ethernet pre-std-detect

Otherwise, you need to force the switch to allocate it 15.4w instead of 7w:

int nn poe-allocate-by value

int nn poe-value 15

(alternatively I think you can allocate-by class instead, and make it class 3)

and do a 

show power-over-ethernet brief

to check you aren't exceeding your switch power budget.

[James Thomsen]

Thanks for your suggestions, unfortunately they have no effect.  The phone still goes into low power mode. The results of the "show power-over-ethernet brief" command for port 23. 

  23    | Yes    low      value 15 W  4.8 W              Delivering  3

15 Watts are allocated, but the phone only uses about 5, it is detected as a class 3 device though.  I suspect Cisco has done something "unique" with the phones which prevents the HP switch from negotiating full power.  I'll post in a Cisco forum and see if anyone has any ideas.