Unable to use Power over Ethernet with a cisco 3500

Older Cisco "Inline Power" switches like the WS-C3524-PWR-XL-EN were designed before the 802.3af "Power over Ethernet" standard was finalized. As such it will ONLY work with Cisco phones and access points. Inline Power and PoE are 2 different animals.

Grandstream (and all other PoE devices) are designed to work with PoE switches or injectors.

The issue is that switches talk via CDP with Cisco devices regarding inline power support. If a device can't talk CDP the switch doesn't enable inline power to protect his port from overload.

The only thing you can do is use inline power injectors. Even pre-AF Cisco Injectors work by changing the pin layout. While normally using a straight cable to connect a device to a switch port you just need to swap pin 4/5 with 7/8.

Switch ---Swap cable --- Cisco AF Injector --- Straight cable --- Grandstream

Swap Cable:
1-----1
2-----2
3-----3
4-----7
5-----8
6-----6
7-----4
8-----5

Configure your cisco ports as:

power inline delay shutdown 20 initial 300

I have prove, and it work!!!!!

Regards,
Rafael

"Inline Power and PoE are 2 different animals."

not to be nit-picky but: Inline Power is PoE. I think what you meant to say is: Inline Power PoE and 802.3af(industry standard) PoE are two different animals.

Power over ethernet is just a generic term to describe supplying power through an ethernet cable. Inline is pre-IEEE standared Power over Ethernet and still qualifies as PoE, just a different flavor. This is similar to the way that 802.3at is/will be considered PoE.

Great post, I just thought I'd throw that out there.