Re: ethernet jack

snertking wrote:
Reed wrote:

bob@xxxxxxxxxxxxxx wrote:

Why does ethernet use a different jack than the phone system? (RJ45 vs
RJ11)?

Possibly because the *plugs* are different ?? :-)

One reason is so you don't plug a PC's NIC cable into a phone jack and destroy it when the NIC gets hit with the 90 volt ringing signal of a phone call.

BTW, the use of the term "RJ-45" for LAN jacks and plugs is, was, and always will be technically incorrect. The entire RJ-series of Registered Jacks and Plugs are telephony applications. The early LAN builders liked the 8 pin 8 conductor form of the mini-modular series so much they usurped it for their use, apparently not being imaginative enough to label it something appropriate to LAN applications. I suppose they were tired of the grief they got over the infamous AUI slide-lock connector they decided not to risk their own design again.

If you are curious, RJ-45 correctly means a "data modem with programmable transmit level" operation. The installing telco would install a resistor within the jack, after selecting a value that would tell the attached modem what transmit level to use to insure the modem's signal reached the local telco CO at a -12dB level, accounting for the loop loss of that specific installation.

If you get the impression that I have been on a 20+ year, Don Quixote-like, crusade against the usurpation of the term RJ-45, you are most correct.

--reed




OK, then maybe we can all start calling them RJ-48 connectors
;-P

Now don't get me started on T-1 access jacks ;-)

(or we could call them "ya know, those 8 pin modular jacks used for ethernet"?)


Sadly today, no one would know what you meant....


.

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