RJ? 4

[clarke123]

Just always wondered what does the RJ stand for in rj45, rj21, rj11,......?

 

[skip555]

i beleive its registered jack as they wiring config was registered

 

[clarke123]

Well that would make sense. Thanks

 

[curlycord]

RJ stands for Registered Jacks(Skip is right). These are telephone and data jacks or applications registered with the FCC. Numbers like RJ-11, RJ-45, etc. are widely misused in the telecommunications industry. They are not actually jack types. A much more precise way to identify a jack is to specify the number of positions (width of opening) and number of conductors. For example: "8-position, 8-conductor jack" or "6-position, 4-conductor jack".

http://www.spoctel.com

 

[jerryreeve]

as curlycord states the "rj number" is often mis-stated, even the 8X8 or 6X4 naming can get you in a bit of trouble if you are using a wiring pattern that needs more than 1 pair. by that I refer to specifically the 568A and B patterns although the USOC standards aren't always used in telephone work. On an installation, I beleive in clearly marking in the equipment room the standard used. This stemmed from working on a location that, for whatever unknowable reason, there was a mix of 568 A and B (it was a mess to keep straight.)

For a fairly deep monograph on the subject of Jacks and Plugs try:

http://www.shout.net/~wildixon/telecom/rj/rj.html

JerryReeve
Communications Systems Int'l
com-sys.com

 

[wmdowns]

Below was copied and pasted directly from a technical manual I found on the net.
ENJOY!


The Universal Service Ordering Code (USOC) system was developed by the Bell System and introduced by AT&T® in the 1970s to connect customer premises equipment to the public network. These codes, adopted in part by the FCC, Part 68, Subpart F, Section 68.502, are a series of Registered Jack (RJ) wiring configurations for telephone jacks that remain in use today.Registered Jack numbers end with a letter indicating the wiring or mounting method being used.· "C" —Identifies a surface or flushmounted jack. · "W" —Identifies a wallmounted jack. ·
"S" —Identifies a single-line jack. ·
"M" —Identifies a multi-line jack. ·
"X" —Identifies a complex multi-line or series-type jack.
You'll also often see these terms associated with USOC:
"T/R" —Denotes connections to the tip and ring wires of a telephone communications line, trunk, channel, or facility.
"A/A1" —Signifies connections to the hold functions of key telephone systems. The "A" lead corresponding to a particular telephone line is shorted to the "A1" lead when that line is off-hook in order for that line's "hold" functions to operate correctly. ·
"Bridged" —Signifies a parallel connection. ·
"Data" —Data configurations use jacks that incorporate components to limit signal power levels of data equipment.

USOC Type of Jack
RJ-11C Surface- or flush- mounted jack
RJ-11W Wallmounted jack
RJ-48X Surface-, flush-, or wallmounted jack
RJ-45M Surface-, flush-, or wallmounted jack
RJ-45S Surface-, flush-, or wallmounted jack
RJ-48C Surface-, flush-, or wallmounted jack
RJ-48S Surface-, flush-, or wallmounted jack

 

[PhoneGuy2000]

The USOC quote is correct but incomplete. to expand on what Curly cord said, People use RJ designations just like Kleenex, Xerox, and Coke.

RJ11 - a 4 or 6 position jack with Tip and Ring on the center 2 pins
RJ14 - a 4 or 6 position jack with tip and ring on the center 2 pins and Tip1 and Ring1 on the next 2 pins out from the center
RJ125 - a 6 position jack in addition to RJ14 has Tip2 and Ring2 on the outermost 2 pins.
RJ45S - a 8 position jack wired with Tip and Ring on pins 1 and 2 and Tip1 and Ring1 on pins 5 and 4 in 12345678 configuration (typical application is a T-1 circuit)
RJ48C - a 8 position jack wired with Tip and Ring on pins 1 and 2 and Tip1 and Ring1 on pins 7 and 8 in 12345678 configuration (typical application is a 56K circuit)
RJ21X - a 50 position/25 pair block with a "Champ" or Amphenol style connector on one side used to create a point of demarcation from the Local Telco.

Also, 568A is the old EIA TIA wiring standard, 568B is the Current wiring standard and has been revised (global engineering documents or bicsi.org) T568A is a termination style. It is prevalent in Government installations and is the termination style recognized now for the home market (see TIA570). Its unique characteristic is that the first 2 pair are terminated to the center pins like an RJ14. T568B is a termination style equivalent yo the old Bell 258A style. It is extremely prevalent in commercial Network wiring. Incidently, AT&T used the 258A/T568B wiring for its proprietary phone systems. To spite them, the Government proposed the T568A wiring standard. Because of the large installed base, the created 568B as an acceptable alternative.

Larry McNeill, RCDD
lmcneill@rx-tech.com

http://www.bicsi.org

 

[PhoneGuy2000]

In my last reply, reverse the RJ48S and RJ48C definitions.

also, check out this link

http://www.levitonvoicedata.com/learning/usoccodes.asp

and

http://www.levitonvoicedata.com/learning/training.asp