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Cisco 7940 on HP5406 PoE

DM1967
Occasional Contributor

Cisco 7940 on HP5406 PoE

I have just installed 3 x HP 5406 with POE. It seems the cisco 7940 phones won't work with the pre-standard PoE.

 

Has anyone had this issue?

2 REPLIES
RK_br
Advisor

Re: Cisco 7940 on HP5406 PoE

It has been tested and should work, make sure that on the switch "pre-standard detect" is on (it is usually on by default)

 

power pre-std-detect

 

 

Good luck

-RK

DM1967
Occasional Contributor

Re: Cisco 7940 on HP5406 PoE

Pre standard is on.

 

I have read that on the earlier Cisco 7940 phones the polarity is reversed for PoE as opposed to what Pre standard supports. ie on the early 7940 (and 7960) pair 4 and 5 neg pair 7 and 8 positive whereas pre standard supports pair 4 and 5 pos pair 7 and 8 neg.