[MLB-WIRELESS] Power Over Ethernet in a 5 1/4 inch bay

[Denis Dowling]

> -----Original Message-----
> From: Matthew Boyd [mailto:Matthew.C.Boyd at uts.edu.au]
> Sent: Tuesday, 12 March 2002 4:00 AM
> To: melbwireless at wireless.org.au
> Subject: Re: [MLB-WIRELESS] Power Over Ethernet in a 5 1/4 inch bay
>
>
> >From the pics I think this is using a separate cable for power and one
> for ethernet? Is this right? If its not all on the one cable, then I'd
> prefer to use a different plug on the power lead to reduce the
> possibility of catastrophic errors.

They were using some of the spare pairs in the Cat5 to run power to the
access point. This way you get power to the access point for free.

>
> I'm thinking about doing a similar thing but want to mount a pc in a
> weather proof container. I figure I'll just run a 4 core cable (got
> some good stuff from work) to the PC, problem is that the Motherboard
> connectors have 10ish pins on them. As far as I know the power supply
> box puts out 12v and 5v. Is there a reason I couldn't run a 4 core to
> the box and then hang a motherboard plug off the end? I've had a hunt
> for the specs but can't find out what each pin carries for me to work
> out if it's possible.
>
> Questions are, is it possible and where can I get the power input specs
> for say a Pentium 100 from.

Have a look on the top of the power supply. Most of the time the ratings are
here. For a Pentium 100 you can get away with just +5V and +12V (ATX
motherboards need an additional 3.3V supply). The -12V output from the power
supply is only used on VERY old motherboards and for powering the RS232
ports. You are going to have to watch the voltage drop over the long to your
motherboard. You should connect up the cable between power supply and
motherboard and check the voltage drop. Anything more than 0.5V on the 5V
supply is going to cause problems.


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