On Sat, Feb 18, 2012 at 1:19 AM, Bob Vaughan <techie@w6yx.stanford.edu> wrote:
"Ethernet/Token Ring/Cisco Console/whatever uses an RJ45 connector" RJ45 defines a keyed 8P8C type connector, wired in a specific manner, for a specific 2 wire telco service. Incompatible with the above on several levels. "RJxx" == specific connector/wiring pattern for specific telco applications. Non-telco uses need not apply.
RJ45 is really an example of what was originally a misconception became so widespread, so universal, that reality has actually shifted so the misconception became reality. When was the last time you ever heard anyone say "8P8C connector?" Joe public caught on to "RJ45", so now that word means something different in common usage than what it was specified to be. When was the last time you heard someone say 8P8C connector in reference to Ethernet? Nowadays it is technically ambiguous to say "RJ45"; are you talking about [a] The original standard, Registered Jack 45, which was a specific connector together with a specific pinout (which is not Ethernet over UTP)? Usage of the connector is exceedingly rare, and will hardly ever be referred to. Or [b] "Ethernet" connector; The generic 8P8C connector (which has a certain resemblance to RJ 45) is specified for use with TIA/EIA 568 compliant cable termination ? Now instead of [a] being correct and [b] being always the misconception..... [b] is "correct" in common usage. And you have to decide based on context of the conversation which defintion of RJ45 is intended, but [b] will almost always be the correct definition. -- -JH