atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring telephone jack standard for commercial

Remember guys, at one time the idea was data on pins 1,2,3 and 6, phone on 4 & 5, and 7 & 8 Future. Future = Spare 'cause we don't know what to do with the other pair from this 4-pair AT&T unloaded on us.
Now I've REALLY confused icpeanuts!And if he thinks there's lot's of money in this field, somebody set him straight.
Who, me, bitter? NAH!
John C.

Speaking of a standard...
How come non phone people (usually data or electricians) instinctively install phone jacks upside down, with the tab on top?

since electrical outlets are installed with the ground up it probably makes sense to them

That makes sense. Another reason may be that most of us have thumbs on the top. :thumb:

What I don't get is why they didn't use pairs 1-2 and 7-8 for data, leaving the middle two pairs for phone lines 1 and 2. As it is, if you plug a data cable into an 8 position, two-line, phone jack, it will apply voltage to the data circuit that is using pair 3-6 and possibly fry it, expecially when the phone rings.

Michael:

The origin of the 8P8C plug/jack in mainstream use came long before data ran on anything but coax. AT&T's systems in the early 1970's required three pairs, sometimes four for long runs on their electronic sets. They set up their own pin assignments, one for voice, one for data and one for power. Again, this was years before 568A/B was even on the drawing board.

I would assume that since AT&T systems were dominant in many major markets, their wiring became the "standard". Their wiring pattern is what is known today as 568B. I would imagine that if their systems hadn't been developed with this wiring pattern, 568A would be the only standard today.

I guess the simple answer is that the concept of LANs as we know them today didn't exist back then. As they today's LANs developed, they were adapted to work in harmony with what had pretty much become the wiring norm.

Also private line data, to two digital data circuits do use pins 1,2 and 7,8. To me data is not the same as computer network wiring. Also a 4 wire phone system wouldn't fry anything on a computer network as pins 3,6 if used would be the digital portion of the phone system so there's just not that much voltage. As far as plugging the incoming lines into a network jack, well that's a good arguement for using the right jack for the job you're doing.

What I heard was this.

Back when TIA/EIA was coming up with a wiring standard for data networks, they were essentially strong armed by AT&T to use their prevalent pattern as we know it today, 568B. Essentially, w/o an AT&T approval on a new standard back then was like toothpaste w/o an ADA emblem stamped on the tube. So the compromise was 568A, everyone was happy; AT&T could still keep their equipment running on the new wiring standard and the TIA/EIA felt as if they didn’t really give in to it.

Like i said this is what was told to me.

~r

Rusty, that might have been what you heard BUT ----

Bell Specs were in use before anyone even heard of TIA/EIA.

568B came first, 568A came only about 10 years ago.

568A was pushed by the off-shore manufactureres so their two pair telephone sets would x-connect straight. The IT types loved that as one patch panel could do data and voice.

icpeanuts as U work in your area and find the work of others and see what shceme they used. For data pick either 568a or b. Make sure that all ends match. jacks, patch panel, patch cords, etc... I my area we use 568b and I have not come cross one using 568a. Maybe one time long time ago. Most phone business systems use one pair now. 4 and 5 are the pins used,that's the same for rj11,568a,and 568b. Sets a standard for yourself and use it until you find a need to change it. U will get the hang of it. Good Luck!

If your terminating to a patch panel then it doesn't matter a two pair will work fine on either scheme .

so the same patch panel always will do two pair a or b

it only becomes a issue if your terminating one end to a block