7960G & Netgear Switch (FS752TPS) - POE not working

williamLisaw · ‎08-11-2008

My company currently installed some 7911G and 7960G VOIP phones. We have a Cisco 1861 Router and a Netgear Prosafe (FS752TPS) 48-port (24 POE) switch. We got the 7911G to work with POE but the 7960G won't.

Do I need a Cisco Power Splitter? Cross-over cable (if so, what is the layout for it)? Cisco POE injector? Or just use a power cube?

Any and all help would be greatly appreciated.

TIA,

WL

Rob Huffman · ‎08-12-2008

Hi WL,

I think you have discovered that the 7940 and 7960 models are supported by Cisco pre-standard power and not IEEE 802.3af from the Netgear as shown below;

Q. What IP phone models support the Cisco pre-standard method of powered device detection?

A. These Cisco IP phones can accept Cisco pre-standard PoE from a card integrated with a Cisco Catalyst switch or a Catalyst in-line power patch panel:

7985G

7960G

7940G

7910G

7910G + SW

7912G

7905G

7902G

These phones can draw local power from a power cube (CP-PWR-CUBE-2=) in addition to a country or regionally specific power cord (CP-PWR-CORD-xx=).

Q. What IP phone models support the IEEE standard method of powered device detection?

A. These Cisco IP phones support IEEE 802.3af PoE:

7961G-GE

7971G-GE

7931G

7911G

7941G-GE

Note: These Cisco IP phones support both the Cisco pre-standard PoE and IEEE 802.3af PoE:

7970G

7961G

7906G

From this doc;

Power over Ethernet (PoE) Power Requirements FAQ

http://www.cisco.com/en/US/products/hw/phones/ps379/products_qanda_item09186a00808996f3.shtml

I have not tried these products, (Cisco PoE switches are all backwards compatible) but this is what you are referring to. It might be easier to just go with the Power Cube but the Dongle may be worth a try;

PD-PS-401-Cisco Passive splitter for Cisco

http://www.simnetsa.ch/upload/File/Microsemi/PowerDsine_Product_Selection_Guide.pdf

http://microsemi.com/PowerDsine/Documentation/SelectionGuide/SelectionGuide.pdf

Hope this helps!

Rob

Rusty Haferkamp · ‎12-10-2008

I am a fan of the Cisco switch coupled with their phones. We have had a very stable environment.

For testing purposes are there other less expensive PoE switches that support the 7940G and 7960G phones or is the Cisco inline power or cube the only answer?

Thanks!

wesleyterry · ‎12-21-2008

So as Rob mentioned, the powerDsine product from microsemi has a dongle that converts the 802.3af to support phones that are pre-standard power.

Basically it swaps two pairs but I don't remember which ones. You could do the exact same thing with a custom cable. I've had to make some custom cables before when I ran out of the dongles. Works like a charm.

I'm just sure it isn't Cisco "supported"