[Asterisk-Users] IP Phone with Standard Power Ethernet

[Kevin P. Fleming]

Tom wrote:

> Cisco supports 802.3af with a special cross-over cable which is easy and 
> cheap to make.

Nope, Cisco phones do _not_ support 802.3af. With the cross-over cable 
you can make them work off a 'dumb' power injector, but a true 802.3af 
injector without Cisco-proprietary support will not supply them power, 
as they will not negotiate for it since they don't support the same 
protocol. On top of that, a switch with built-in PoE can choose to 
supply power on the _data_ wires instead of the spare wires (which is 
fully supported by the spec), in which case a Cisco phone would have no 
hope of working.