Re: pic network thingy

[swelsh000]

The 802,3af standard has just been ratified, should be published by
next month.

<a href="http://grouper.ieee.org/groups/802/3/af/";>http://grouper.ieee.org/groups/802/3/af/</a>

>
> POE is a definite requirement, but Cisco's probably isn't... it's
the opposite polarity to everyone else!

Cisco's is the same polarity as the 802.3af standard:

7,8 -ve (source)
4,5 +ve (return)

I suspect things should now migrate to the standards based POE
method.

Cisco will now release their Catalyst 2950T-24PWR, 24 Port of POE
with 2 1000BaseT ports. This model has been held back until the
standard has been ratified. This will be the most cost effective way
to get an excellent spec'd switch with standards based POE.

I'm guessing it will cost £1233 UK List, £666 Global Cost, so you
should be able to get it for about £900.

If you are looking for a cost effective 802.3af 'hub' (just supplies
power in a patch through from switch) otherwise known as midspan
power.

<a href="http://www.powerdsine.com/";>http://www.powerdsine.com/</a>

They have been key to the 802.3af standard, so I'm sure they will
have some certified products for shipping real soon, if not already.

Power available per port is typically 15Watts, not bad for a Cat5
cable!

>
> That being said.. I have this idea that if I use a bridge
rectifier on the power inputs, it will automatically give me both
polarity protection for DC power, and also rectify AC power, so *in
theory* with some clever component selection (max reverse voltage
etc) I could run off of Cisco +- 48V DC, Intel -+ 24V DC, or
Homebrew -+12V AC

Powerdsine have recomended the use of a bridge rectifier for POE,
primarily for when mistakes are made i.e. plugging in a crossover
cable etc. but this is more relevant to used pair power.

Thanks

Stephen


>
> Would be handy!
>
> Ian.
> ----- Original Message -----
> From: Dean Smith
> To: <a
href="/group/ukha_xpl/post?postID=GyAajGw-oDqD24qFv2uSzUFpUYscHyDGiDWp8X2VndTVGLY7JLI33zjEb15eXSbbD5sPoBed1t6zuY7uT9ft82ot">ukha_xpl@xxxxxxx</a>
> Sent: Saturday, June 07, 2003 11:52 AM
> Subject: RE: [ukha_xpl] pic network thingy
>
>
> Ian
>
> Which PIC will you be using - and can you fit both IP and XPL
code into it ?
>
> <Fantasy Mode On>
> If it uses power from the ethernet I could "borrow" the
spare
Catalyst 6506 and 48 Port Powered Ethernet card from work.....
> <Fantasy Mode Off>
> Then cover it in 10 layers of sound proofing so I cant here the
fans !
>
> Dean
> -----Original Message-----
> From: Ian Lowe [mailto:ian@w...]
> Sent: 07 June 2003 11:42
> To: <a
href="/group/ukha_xpl/post?postID=GyAajGw-oDqD24qFv2uSzUFpUYscHyDGiDWp8X2VndTVGLY7JLI33zjEb15eXSbbD5sPoBed1t6zuY7uT9ft82ot">ukha_xpl@xxxxxxx</a>
> Subject: Re: [ukha_xpl] pic network thingy
>
>
> That's my first project ;)
>
> Ian.
>
> ----- Original Message -----
> From: Steve B
> To: <a
href="/group/ukha_xpl/post?postID=GyAajGw-oDqD24qFv2uSzUFpUYscHyDGiDWp8X2VndTVGLY7JLI33zjEb15eXSbbD5sPoBed1t6zuY7uT9ft82ot">ukha_xpl@xxxxxxx</a>
> Sent: Saturday, June 07, 2003 11:33 AM
> Subject: Re: [ukha_xpl] pic network thingy
>
>
> Ian,
>
> Will there be any ethernet to the vac displays in the
pipeline ?
>
>
>
>
> xPL Links: <a href="http://www.xplproject.org.uk";>http://www.xplproject.org.uk</a>
<a href="http://www.xplhal.com";>http://www.xplhal.com</a>
<a href="http://www.xpl.myby.co.uk";>http://www.xpl.myby.co.uk</a>
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