On 12/14/2006, Daniel Roman wrote:
I'd like to take this opportunity to point out the misuse of the "RJ-45" name when really what is meant is an 8-position modular jack. RJ-45 refers to a specific T1 wiring scheme using an 8 position modular jack (8P4C). Similarly, we often see RJ-11 misused as well. RJ-11 is a 2 wire connection utilizing a 6-position modular jack (6P2C) and RJ-14 is a 4 wire connection also utilizing a 6-position modular jack (6P4C). These all date back to the Bell System USOC (Universal Service Ordering Codes) that have been used and misused for years. I cringe every time RJ-45 is used when referring to Ethernet. I'm not an old Bell System guy who wrote these specs originally, but I guess it is a pet peeve of mine! I'm constantly correcting the engineers I work with. :-) Hi Dan: Well, I'm an old Bell Labs guy and I no longer bother to correct people when they use the RJ-11 and RJ-45 terms to describe modular plugs and jacks. In fact, I now use those terms myself. Like many other technical terms that have morphed over time, I think these terms have entered the engineering vernacular and we are unlikely to excise them at this point. I think that one problem with calling them "modular connectors" is that this term may not be sufficiently specific for clear communication. To some people, the term "modular connector" might sound like a generic description of a broad category of connectors that is not limited to the specific connectors we have in mind. On the other hand, the terms "RJ-11 connector" and "RJ-45 connector" seem to be widely recognized and unambiguous for most people, even if the definition these people associate with each term is not strictly correct with respect to the original meaning of the term. There are numerous other examples of such evolution of terms within the telecom industry, such as DAA, FXO, and FXS, which are also routinely used to describe something different from what they originally meant. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) [email protected] http://www.randolph-telecom.com <http://www.randolph-telecom.com/> ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
