Hello, Mr. TechmanJed:
The Universal Service Order Code (USOC) was developed between the Bell System and the FCC as a uniform standard for ordering network connection jacks. These registered jacks (RJs) were devised so that a customer could order their service from any telephone company in the country and be assured of receiving the exact same thing. For example, an RJ11 is a single CO line appearing on pins 3/4 of a 6P4C modular jack, an RJ21X is a block containing up to 25 CO lines, etc.
There never was an RJ9, RJ10 or RJ22 handset connection developed under this program. USOC "RJ" designations are wiring patterns upon different types of jacks, not specific pieces of hardware. Additionally, any "RJ" designation ends at the wall. No component of a telephone set has an "RJ" designation, period.
The fact that you and yours have developed your own home-grown connector terminology is all well and good, but don't come here with the intention of insulting others with your inaccurate information. I challenge you to take a handset cord from a Toshiba phone and plug it into the handset of an AT&T Trimline phone and expect it to work. This little test itself should prove that there is no uniform standard in handset jack wiring.
From another forum:
RJ-numbers are well defined standards in a telco environment. It describes signal names and wires used on several plugs/jacks. So using the name RJxx in a data network or other non-telco environment is misleading. It is about the same common error like using RS232 for a DB25 or DB9 connector. As a wiki article has stated, handset leads and the like have no RJ-- definition, being a part of an appliance, not of the network itself. There is no official standard for this type of connections, nor can there be, so 4p4c is the best you can name it. At the same time you'd better be aware that not all manufacturers use the same pin out.
HERE IS SOME ADDITIONAL SUPPORTING INFORMATION Oh, and Mr. TechmanJed, I'd think twice about coming here, dragging up a thread that started 3.5 years ago and slinging insults at senior management of this forum in the future.