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Community Member

Adjusting POE on Cisco 3750

I know currently on the 3750 with POE that each switchport gives out 15.4W of power automatically be default. I am trying to find out if there is a way to decrease this value to a lower W for class 0 or class 3 devices. Does anyone have any information on this, or if it could be done. I have not seen anything in the Cisco technical documents.


Cisco Employee

Re: Adjusting POE on Cisco 3750

The maximum power a port in a 24 port inline powered 3750 is 15.4W and it is not a fixed value. Are you having any issues with powering certain devices? If so, please open a TAC service request and have it addressed.

Community Member

Re: Adjusting POE on Cisco 3750

We are going to be connecting the following platforms of IP Phones to the 3750, that have the following wattage requirements.

Avaya 4610 average watts is 4, worst case 6

Avaya 4620 average watts is 6, worst case 8 (Class 3)

Avaya 4612 average watts is 5, worst case 6.5

Avaya 4624 average watts is 5, worst cast 6.5

As you can see, we do not need to provide 15.4W per device, due to the fact that it does not need that amount. We are just needing to know how to adjust the POE requirments at the port level. If you have any suggestions, please let me know. Thanks for your help.


Community Member

Re: Adjusting POE on Cisco 3750

As long as the Avaya phones you mention meet the IEEE 802.3af Power over Ethernet standard, they should work fine automatically with the Cisco switch. As you mentioned in an earlier post, inline power is automatically supplied on the 3750 ports. The IOS command "power inline" is set to "auto" by default according to:

Although each port can supply up to 15.4W, each phone will only draw as much power as it needs individually. The concept is similar to a battery in a flashlight--if the switch isn't turned on, the electrical circuit remains "open" and no current flows. In other words, no power is transferred from the battery to the lightbulb. But even if you have huge batteries, the lightbulb is only going to draw as much current as it needs to stay lit.

I would suggest testing one phone of each type with the switch before a full production install, just to be sure you won't have interoperability problems.

For more info on Power over Ethernet, check out:



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