According to Michael A. Terrell :
"DoN. Nichols" wrote:

796) A "modular phone plug" model RJ-11. (RJ-13 is the six-conductor
one, and RJ-45 is the eight conductor one, which is used for
twisted pair ethernet among other things.


Actually, the "RJ" numbers are wiring patterns for specific
applications, not the connectors. They are named *p*c, for the number
of postions and the number of conductors.

Hmm ... the phone company (the originator of these, IIRC) uses
RJ-48 for both of the wiring patterns on the identical connector for a
feed from a T1 box on the side of the house to the DSU in the house.
The only difference is the suffix which indicates the differing wiring
pattern for the transmit and receive pairs. The one which I am using is
RJ-48C. I forget what the other one was.

However -- the 8-pin connector involved is usually referred to
as a RJ-45



A somewhat narrower version is used for handset cords for phones
of a certain age.

That is the 4P4C wired as a four conductor handset cord. The one in
picture 796 is the 4P4C, as used for handsets.

I don't believe so. The one shown has the fatter side walls,
producing a connector the same width as the 6-pin version. You can see
the grooves which would accept the extra blades (and in this case,
simply prevent damage to the wire pins in a 6-conductor jack).

The 4-pin used in the handsets (at least in the old ITT one in
my hand at the moment) is narrower, and does not have the unused grooves
outside the four in actual use.


http://www.levitonvoicedata.com/learning/wiring.aspx is a link to some
common RJ numbers.

But -- it does not show the RJ-13, and a Google search for that
seems to be confused by someone who has been posting under the name
"rj13".

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---