PoE ...

#1 (**permalink**) 10-24-2006, 09:19 PM

Hi,

I saw that some phones (Like the SPA-942) offer the possibility to use
the hub as power...

I suppose that this is s specific hub ?
I suppose that it won't work with a normal hub ?

Thanks and regards

#2 (**permalink**) 10-24-2006, 11:28 PM

Stephane M wrote:
>
> I saw that some phones (Like the SPA-942) offer the possibility to use
> the hub as power...

Usually a switch now. People don't tend to use hubs anymore.

> I suppose that this is s specific hub ?

You can either use a powered switch, or you can use inline POE injectors
and keep your normal switch.

Phihong make a good range of power injectors.

> I suppose that it won't work with a normal hub ?

It will be fine. The way power over ethernet works, is that the power
is only switched on when the switch or injector detects a valid PoE
device on the end of the cable.

This way, no damage is caused if a not PoE device is attached.

PoE injectors also have over current detection, so the power is shut off
in case of short circuit. This is before your 100m of Cat5 acts like a
heating element and melts.

The standard for PoE is IEEE-802.3af

Tim

#3 (**permalink**) 10-25-2006, 05:27 PM

Stephane M wrote:
> Hi,
>
> I saw that some phones (Like the SPA-942) offer the possibility to use
> the hub as power...
>
> I suppose that this is s specific hub ?
> I suppose that it won't work with a normal hub ?
>
> Thanks and regards

Stephane

Make sure the devices you buy are compatible. For instance, the 3Com
4400 PWR and NJ205 claim 802.3af compatibility, but in reality they only
work with other 3Com devices. Apparently the newer 5500 switches are
more compatible. I have never had any trouble with injectors made by
powerdsine.

Regards

Chris

#4 (**permalink**) 10-25-2006, 11:38 PM

Stephane M wrote:
> Hi,
>
> I saw that some phones (Like the SPA-942) offer the possibility to use
> the hub as power...
>
> I suppose that this is s specific hub ?
> I suppose that it won't work with a normal hub ?
>
> Thanks and regards

I am running a set of Grandstream GXP 2000s on a Netgear ProSafe FS108P
network switch. The switch has 8 ports, 4 of which do PoE. A decent
solution for small offices - switch is about £79 inc VAT.

L3K