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Investigating an "evil" RJ45 dongle

(lcamtuf.substack.com)
320 points zdw | 2 comments | 17 Jan 25 20:41 UTC | HN request time: 0.479s | source
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baq ◴[17 Jan 25 20:53 UTC] No.42743115[source]▶
RJ45 nazi here: these should be called 8P8C

I’ll show myself out

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leptons ◴[17 Jan 25 21:27 UTC] No.42743463[source]▶
TIL. After maybe 25 years of using this connector, I've never heard it called 8P8C. I knew Ethernet has used other physical layers including coax, which I used to run between Amigas way back in the day. But, today I finally learned about 8P8C.
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SAI_Peregrinus ◴[17 Jan 25 22:07 UTC] No.42743794[source]▶
RJ45 isn't even actually the same connector, at least not in the original FCC naming. That was an 8P8C keyed modular connector. RJ45 connectors had only two of the positions connected to wires (one phone line) an internal resistor between two of the other positions, and a keying bar that stuck out of the plug so they wouldn't even go into the unkeyed 8P8C jacks we use for Ethernet.

So I'll still call them RJ45 connectors. Because nobody has time to say "8P8C unkeyed modular connector" every time!

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1. Brian_K_White ◴[18 Jan 25 02:11 UTC] No.42745192[source]▶
Similarly, it's DE9 not DB9
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2. SAI_Peregrinus ◴[18 Jan 25 03:31 UTC] No.42745564[source]▶
Yep, and these days ribbon cables are rare, instead we have Flexible Flat Cables or Flexible Printed Circuits. Ribbon cables are the old cables like IDE hard drives used, with insulation displacement connectors, while FFCs and FPCs are much thinner and use integral connection schemes (tinned pads on the cable itself get clamped by some sort of connector on a PCB).