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Cisco 3750 PoE Switches

Cisco 3750 PoE Switches

Cisco 3750 PoE Switches


Hopefully someone has seen this issue before and can help.

We have (more than 1 but will just use 1 as an example here) a PoE 3750 switch, that, from my understanding has a PoE output of 370 Watts. We recently attempted an IPT rollout of Cisco 7942G IP Phones at our London offices. From my knowledge these IPT phones are a Class 2 device and therefore should only draw 7.5 Watts per device. This means 48 devices should be able to be attached to the PoE switch with no problems. When we got to 17 devices and added the 18th, we noted it was getting no power to the switch. Upon checking the switch we noted the PoE light flashing "Amber". To confirm power consumption had been reached we disconnected 1 and hey presto, the other came up. We could only get 17 devices to draw power from the switch. This resulted in a very quick rollback and has left us in a very awkward position.
Please note this is a third partry managed system so I cannot get any command references or any access to the switches.

On top of that, in their wisdom, the second switches enabled for the IPT VLAN were configured on non PoE switches. Marvellous.

Any help or knowledge regarding this would be great.


RE: Cisco 3750 PoE Switches

It's all good. I think we have found the problem. Would help if the PoE switches had been supplied with the correct PSU .... doh

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