RJ45 is a specific AT&T USOC order code to slap a normal 8P8C jack on someone's wall to provide something like multi-line analog telephone service.

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LukeShu 5 days ago | parent | next [-]

RJ45 is a keyed 8-position jack, not a normal 8-position jack. ("Keyed" means that there's a notch in the side making it a different shape; you would not be able to fit an "Ethernet" connector into it.)

Closer is RJ38X, which is a series 8-position jack, not a normal 8-position jack. ("Series" means that the jack shorts pint 1 to pin 4 and pin 5 to pin 8 when there's not a cable plugged in to it; you would be able to fit an "Ethernet" connector into it, but even so it's probably not what you want.)

AFAICT (skimming 47 CFR part 68, and the historical AT&T documents that became 47 CFR part 68), there is no RJ-number for a normal 8-position jack.

	▲	pests 5 days ago \| parent [-]
		> you would not be able to fit an "Ethernet" connector into it Because of the size being different? Surely a keyed female plug will take a male connector with or without the key. Or did you mean you couldn't fit a RK45 connector into a Ethernet plug because then the key would interfere?

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arghwhat 5 days ago | parent | prev | next [-]

RJ45 is a mechanically (slightly) different connector, but indeed all RJ specs were for phone lines, with RJ45 focused on several lines for high speed modem connections.

The regular ethernet 8P8C connector was defined by both an ANSI and ISO spec, neither of which gave the connector an actual name as it covers modular connector designs. :/

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Sammi 5 days ago | parent | prev [-]

I used to do phone support for a phone company / isp and I have no idea what you just wrote.

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craftkiller 5 days ago | parent | next [-]

To be fair, 5 out of the 6 phone support agents I talked to at Optimum (an ISP) did not know what IPv6 is, so saying you used to do phone support for an ISP isn't really saying much.

	▲	gjvc 5 days ago \| parent [-]
		you tell him!

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SAI_Peregrinus 5 days ago | parent | prev | next [-]

RJ45 is a connector with a key notch sticking out and a "programming" resistor joining two of the pins. It won't work for Ethernet at all, the plug side can't even fit in the 8P8C socket Ethernet uses. If you grind off the key it'll still not work, because of the embedded resistor. Also the pinout is totally wrong, so even if you didn't have the resistor it wouldn't work. None of the RJ connectors have the correct pinout for Ethernet.

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SV_BubbleTime 5 days ago | parent | prev [-]

He said RJ45 is an AT&T part/reference number. Just like RJ11 which is your small phone plug that had 6pins, more rare.

	▲	arghwhat 5 days ago \| parent [-]
		Nit: RJ11 has two contacts. RJ11, RJ14 and RJ25 all used the same 6P housing though, making them 6P2C, 6P4C and 6P6C connectors, respectively. Things sold as RJ11 is often 6P4C, making for another error. The rule of thumb is that anything referred to as RJ-something is likely wrong.