T568A or B - Page 3 - Electrician Talk - Professional Electrical Contractors Forum
CLICK HERE AND JOIN OUR COMMUNITY TODAY, IT'S FREE!
Go Back   Electrician Talk - Professional Electrical Contractors Forum > Electrical Trade Topics > Structured Wiring


Like Tree2Likes
Reply
 
Thread Tools Display Modes
Old 09-12-2015, 10:29 AM   #41
Hackenschmidt
 
splatz's Avatar
 
Join Date: May 2015
Location: Parts Unknown
Posts: 7,697
Rewards Points: 2,798
Default

@drsparky -

I read your reply regarding mixing 568A and 568B with interest. With all due respect, I am really skeptical that there's enough of a difference in the impedance between the green pair and the orange pair to have any real difference with data transmissions.

Have you ever actually measured this with your own eyes? I have certified tons of cat5e over the years and it's never been an issue.

One of the testers I have used came with test leads hardwired into a proprietery plug that screwed into the tester. They only gave you one pair of leads; if different leads were necessary for 568A and 568B pinout, they'd have needed to give you two.

Thinking about it more, having bought thousands of patch cords over the years, never had anyone even offered whether to sell me 568A or 568B - if it was a big deal, you'd think people would look for it. LAN admin types are notoriously fussy about details that are of no practical importance.

Regarding impedance, I would think that the length of the conductor is the main determinant. Different twist ratios are going to make the actual length of the conductors a little different in each pair. This skew is at times a problem on long runs with lousy cable. But by mixing a 568a link with 568b patch cords, you'd actually get less of a total difference in lenth between pairs, and more even impedance / delay skew pair to pair. Not that I think that's of any practical importance. (I am admittedly out on a limb with this, please by all means straighten me out if I am off base.)

Anyways - thanks to pain in the axe VOIP systems I have done a LOT of low level network monitoring and etc. this past couple years. I have seen MANY problems caused by marginal patch cords, but not one by mismatched 568a/568b patch cords. So even if there is a measurable difference, I can say that in my experiece, it seems to be within the tolerances of the encoding etc., too small to cause bad packets.
splatz is online now   Reply With Quote
The Following 2 Users Say Thank You to splatz For This Useful Post:
drewsserviceco (09-12-2015), guest (09-13-2015)
Join Contractor Talk

Join the #1 Electrician Forum Today - It's Totally Free!

ElectricianTalk.com - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that ElectricianTalk.com is a great community to join. Best of all it's totally free!

Join ElectricianTalk.com - Click Here JOIN FOR FREE


Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectricianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Sponsored Links
Advertisement
 
Old 09-13-2015, 08:06 PM   #42
Electric Hair
 
vickieB's Avatar
 
Join Date: Feb 2011
Location: Boston, Massachusetts
Posts: 60
Rewards Points: 77
Default

@480 Sparky
Definitely need some cable management in those pictures! What a mess.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
UGH!
vickieB is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 05:06 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Our Pro Sites Network
ContractorTalk.com | DrywallTalk.com | HVACSite.com | PaintTalk.com | PlumbingZone.com | RoofingTalk.com