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RJ-12?

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rpearson

Technical User
Jul 25, 2002
297
US
I have recieved a request by a customer to construct a patch cable consisting of RJ-12 mod plugs on each end per spec.In all my years in this field I have never came accross the term RJ-12(aside from the usual RJ stuff).The spec sheet (Cisco) tels me this will be a 6P6C utlizing only 3 of the pins.Now my assumption is this is going to be a standard RJ-11(telephone)with 6P6C in place,and the term"RJ-12" is just a technical description of the mod plug.Please iterate.Thanks.
 
Just to clarify.....

RJ-11 is a 6P2C connection, in other words: 6 Position, 2 Contact

RJ-12 is a 6P4C connection, in other words: 6 Position, 4 Contact, it does have specific applications for key systems when there are issues of electrical line compatibility with the tip and ring.

RJ-14 is also a 6P4C connection, in other words: 6 Position, 4 Contact

And just for the record...there is no such thing as a RJ-45 in the USOC book, it is a 8P8C connection.

Hope this helps for anyone that is confused.
This is not my opinion, just the facts from the USOC book. :)
 
My USOC book shows a RJ45s as tip (pin 5) ring (pin 4)and a programming resistor across (pins 7 & 8) typical useage is programmed data equip.
 
You are correct, there is an RJ-45S, but not an RJ-45. An RJ-45S is a keyed jack as well, it is basically a 8P4C, and not even close to what people refer to as an RJ-45, since it has a resistor shunting pins 7 and 8, and only communicates on pins 4 and 5.
 
Yes, an RJ25 is a 6 Position 6 Contact connection. The pairs on it are pins 1 & 6, 2 & 5, and 3 & 4.
 
The USOC (Universal Service Order Code) as I understand it is a standard adopted by FCC that defines how particular plugs and jacks are terminated. An RJ whatever does not reference a plug, but more precisely it references a method of connecting a service on a plug or jack. The suffix after the number generally describes the physical type of jack or plug (surface mount, wall mount, etc.)

Now, several posts have loosely referenced some sort of reference material. The "USOC" book sounds interesting, but what specifically is that? I can find references to USOC in my BICSI TDDM, the Newton Telecom Dictionary, old Bell Labs references, etc. So...share the wealth here would ya? Point me to the USOC book and lets see who wrote it and when.

The data industry is terrible at using that RJ-45 designation for what more correctly is an 8 pin modular plug and jack. However, it would be really nice to know the actual answer from the actual source so we can put this to rest.





It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
 
Daron

As a fellow RCDD let me say you are absolutely correct about RJXX designations. Each is a specific type of termination in a specific type of jack/plug.

The book I go by is the USOC book published by Suttle, who as you know has been making jacks since dirt was created. The info in it is reprinted from FCC documents.

I have looked on their web site for a downloadable pdf, but to no avail....sorry...

I have scanned most of them I will package them and put them on my web site for download later.


Hopefully by tomorrow afternoon.

Richard S. Anderson, RCDD
 
Thanks for the reference Richard, very nice work. I have similar documents from various vendors as well, I was hoping to find something with an FCC logo in the corner or something that would definatively show their recognization of the designation, but your reference is very good.

Thanks again for taking the time to compile and upload this information.



It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
 
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