Welcome to the MacNN Forums.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

You are here: MacNN Forums > Enthusiast Zone > Networking > Basic Network Questions

Basic Network Questions
Thread Tools
ghporter
Administrator
Join Date: Apr 2001
Location: San Antonio TX USA
Status: Offline
Reply With Quote
Oct 1, 2020, 09:27 PM
 
I think this may be broader than “just” a networking questions, but let’s have at it...

Let’s start out with this: what is the practical difference between T-568A and T-568B standards for Ethernet connections? Historical relevance aside (apparently T-568B pinout matches an old AT&T system pinout), does it really matter if a particular cable is terminated A or B? In particular, all things being equal, won’t an Ethernet patch cord connect just as well whichever termination pinout it has?

And then there’s Cat6 specific terminations. Since those I have on hand are keystone jacks rather than something else, I haven’t been able to determine if it’s just a layout issue on the punch down jack, if it’s T-568B, or something else... Yes, Cat6 is physically thicker than Cat5, but why do Cat6 keystone markings not match Cat5 keystone markings? Or am I missing something here?

Does this come down to “it’s an in-crowd thing”, or is it something else more practical?

Glenn -----OTR/L, MOT, Tx
     
subego
Clinically Insane
Join Date: Jun 2001
Location: Chicago, Bang! Bang!
Status: Offline
Reply With Quote
Oct 1, 2020, 10:42 PM
 
My understanding is it only matters for compatibility with phone jacks. T-568A can run two phone lines, while B can only run one.
     
ghporter  (op)
Administrator
Join Date: Apr 2001
Location: San Antonio TX USA
Status: Offline
Reply With Quote
Oct 2, 2020, 05:28 PM
 
That's what I thought, but why it's still a thing to begin with boggles the mind...

Glenn -----OTR/L, MOT, Tx
     
ghporter  (op)
Administrator
Join Date: Apr 2001
Location: San Antonio TX USA
Status: Offline
Reply With Quote
Oct 2, 2020, 09:22 PM
 
A little more info here...

It turns out that the "Cat6 specific" thing I was seeing was simply me misreading a picture.

The color code on the side of this keystone jack shows good old T568a/b wiring. It's just the arrangement of the pin numbers threw me. (The other side is appropriately marked for pins 7, 8, 3 and 6 front to back.) These are the keystone jacks I bought to update my network wiring.

Honestly, the color coding (now that I'm actually understanding it...) seems to make this particular jack pretty goof resistant.

You'd think someone who could actually use a 110 punch tool would be able to read numbers, wouldn't you?

Glenn -----OTR/L, MOT, Tx
     
   
Thread Tools
 
Forum Links
Forum Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Top
Privacy Policy
All times are GMT -4. The time now is 02:18 AM.
All contents of these forums © 1995-2017 MacNN. All rights reserved.
Branding + Design: www.gesamtbild.com
vBulletin v.3.8.8 © 2000-2017, Jelsoft Enterprises Ltd.,