[Tfug] Yet another poser

[Bexley Hall]

--- johngalt1 <johngalt1 at uswest.net> wrote:

> ----- Original Message ----- 
> From: "Rich" <>
> To: "Tucson Free Unix Group" <tfug at tfug.org>
> Sent: Tuesday, September 18, 2007 12:11 PM
> Subject: Re: [Tfug] Yet another poser
> 
> > On Sep 14, 2007, at 6:48 pm, Rich wrote:
> -snip-
> > PoE devices still require PoE whatever device
> they're connected to.
> > If you connect a PoE device to a PC, you need a
> crossover cable *and*
> > it should carry power. Real world application?
> Simple:
> >
> > big wide world <-> PC <-> wireless base station
> 
> This still sounds hypothetical.
> 
> > The base station runs off power over ethernet, the
> PC supplies it,
> > but you have to use a crossover cable.
> 
> What, a PoE NIC for your PC? Please specify a make
> and part number.
> 
> Otherwise, you could use a PoE power inserter like
> this:
> http://www.dlink.com/products/?sec=0&pid=332
> 
> Then the crossover cable can be placed between the
> PC and the wart supplying 
> power.
> 
> => No conductors 4,5,7,8 necessary in the crossover
> cable. 

I'm not sure of this.  The whole point of *my* widgets
is that you can insert them with *minimal* and *known*
impact on the interconnections you are modifying.

E.g., I run the "reserved" and "unused" EIA232
signals "straight through" on almost all of my
DB25 (serial) widgets.  "It's just a couple of
extra strands of wire..."

As a result, I can (and often *do*!) cascade
different widgets without introducing any
unexpected side-effects.  E.g., when I *don't*
want the aforementioned signals to pass through,
I insert a M-F widget called "EIA232 defined"
that passes the *defined* EIA232 signals through
and interrupts those that are not.  So, unless
this widget is present, I can count on those
signals being available to me at the end of an
arbitrarly deep "widget stack".

Of course, that's because many old "serial devices"
put things on those extra signals that I *might*
want to have access to -- even though the data
lines aren't as I would want/need them (e.g., null
modem, gender change, etc.).

I don't think this is as common a situation nowadays.
Especially wrt RJ45's.


       
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