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poe don't detect


I have installed a 3560G-24PS, version 12.25 SEB4.

When I connect an IP phone Alcatel to a port it works. POE is detect.

When I use a port with a station , I disconnect the station connect the ip phone and I have no poe detect.

I shut and no shut the port and It works.

I don't understand why ? with an cisco ip phone I have no problem.

The problem is when I connect an ip phone on a port with a pc before, it don't work !!!!! and at each time I make the modification




Re: poe don't detect

Hi Eric,

By any chance have you enabled error detection on your switch. It can be a possibility that changing device is detected as link flap and port goes into err-disable stae. Have you checked for this


Re: poe don't detect

an understanding of exactly what the alcatel phone does when connected to the switch is required to figure out why it is acting a specific way when power is to be applied.

an understanding of the way the 3560 provides power is applied is also helpful.

with a cisco ip phone for instance, we know that a FLP is sent to the phone from the switch initially to determine if power needs to be applied to the port.

if the FLP is looped back to the switch, this tells the switch that a cisco ip phone is connected and to apply power to the port.

the FLP loop is then opened and the phone begins to receive the power and boot up, etc, etc.

i am not sure how the alcatel ip phone operates so you may want to find that out or if you provide the exact alcatel phone model, we can probably assist you further.

please see the following link for PoE operation of a Cisco 3560G-24PS:

please see the following link for PoE operation of a cisco ip phone: