MR56 functioning on 2 pairs instead of 4 pairs?

[AlexGill]

Hello, one of the pairs on the ethernet is damaged, so our MR56 cannot fully function...

I am thinking to re-terminate the jack with the good two pairs for 100BASE-TX Fast Ethernet. But before I do, would this work? Would our MX220 to MR56 do POE and 100Mbps?

[alemabrahao]

I'm not sure, but I don't think so.

[Purroy · Accepted solution]

I think it would work.  PoE 802.3at requires only two pairs to deliver power, with regards to ethernet connection you will only be able to get 100Mpbs as for 1Gbps you need all four pairs.  You might need to force the switch port to 100Mbps speed.

Just to be clear.  The fact that it would work does not mean that you should do it.  Probably replacing the broken cable is the way to go.  That way you will be able to have a good performance with the MR56 and avoid other issues.

[AlexGill]

Thanks for confirming, that yes, technically it could work, and good tip too about forcing it at the switch as needed. I plan to try out this stopgap solution and comment back on how it turns out.

[cmr]

@AlexGill it depends on which pair has failed, we've had plenty of APs survive when pair 4 goes down...

[AlexGill]

Pin one was was bad making the required "pair 2" invalid. So I swapped the orange pair with the unused brown pair at the patch panel and AP jack. The connection is now powered and functioning at 100Mbps, which is better than at 0 Mbps 🙂