Specs for POE on 3com 7250 please ?

Just tried:

4+5 +ve
7+8 -ve

Fed with the points own 3v psu, via a 20M CAT5... and NOTHING !
Do 3com use a different spec ?

In article <oRkRk.18922$(E-Mail Removed)2>,
"Quagmire" <(E-Mail Removed)> writes:
> Just tried:
>
> 4+5 +ve
> 7+8 -ve
>
> Fed with the points own 3v psu, via a 20M CAT5... and NOTHING !
> Do 3com use a different spec ?

PoE uses 48VDC (standard telephony voltage).
If you are building your own power source, make sure you include
suitable current limiting protection (1/3rd Amp, IIRC) so the cable
doesn't burst into flames in the event of a short circuit.

There are two different schemes for feeding the power down the
cable. I don't know which your item uses.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Andrew Gabriel" <(E-Mail Removed)> wrote in message
news:49173796$0$500$(E-Mail Removed)...
> In article <oRkRk.18922$(E-Mail Removed)2>,
> "Quagmire" <(E-Mail Removed)> writes:
>> Just tried:
>>
>> 4+5 +ve
>> 7+8 -ve
>>
>> Fed with the points own 3v psu, via a 20M CAT5... and NOTHING !
>> Do 3com use a different spec ?
>
> PoE uses 48VDC (standard telephony voltage).
> If you are building your own power source, make sure you include
> suitable current limiting protection (1/3rd Amp, IIRC) so the cable
> doesn't burst into flames in the event of a short circuit.
>
> There are two different schemes for feeding the power down the
> cable. I don't know which your item uses.
>
> --
> Andrew Gabriel
> [email address is not usable -- followup in the newsgroup]



So... the original 3v PSU isn't man enough then ! that answers that....
but I have seen DIY adaptors on the net - none that I can remember mention
the higher voltage...