[ale] OT: GigE Copper specs

[griffisb at bellsouth.net]

>  
> From: Greg Freemyer <freemyer-ml at NorcrossGroup.com> 
> > 
> You do have to count the amount of cable that was untwisted when putting 
> on a connector, but that is not a punch down. 
>  
> Punch downs are typically used on patch-panels and first came from phone 
> system wiring, but they are now used in "structured wiring" for 
> networks. 
>  
> You can buy punch down blocks and tools at Home Depot, etc.. 
>  
> Typically, the punchdown block has a lot of metal posts sticking out of 
> a pc board.  The posts are then connected together on the board: 
>  
 
My big punchdown fun was in an office move in San Diego. I worked for a company 
headquartered in Danbury, CT, and put out an RFP. Selected a company to do the 
cabling, and did the status meetings. Flew out to do the move, and out of about 
50 PC's, only came active. Hmmmm - what happened? 
 
The switches looked good (Cisco 5000 series, it was a bunch 'o years back). The 
fiber between switches was good, with Fast Ethernet for backup. Punchdowns 
looked a little odd at the patch panel. Terminations looked good at the 
desktop. 
 
The group had wired all the desktop jacks EIA568B and the patchpanel punchdowns 
568A. This was Saturday AM we finally diagnosed it, with a monday morning live 
date. I grabbed a 110 punchdown tool and re-terminated all the punchdowns on 
the patch panel. That was my first time using a punchdown tool, and probably my 
last. I didn't give the cabling company good references, and don't recommend 
"remote controlling" projects. You have to be able verify what's going on long 
before a live data.