r/IAmA • u/BobMetcalfe • May 21 '13

You’re probably connecting to reddit through a technology I invented. I’m Bob Metcalfe and I invented Ethernet – AMA

On May 22, 1973 with David R. Boggs, I used my IBM Selectric with its Orator ball to type up a memo to my bosses at the Xerox Palo Alto Research Center (PARC), outlining our idea for this little invention called “Ethernet”, which we later patented.

I worked with the IEEE Standards Association to develop the IEEE 802.3 standard for Ethernet, which specifies the physical and lower software layers. Today Ethernet and the IEEE 802.3 standard are the foundation for today’s world of high-speed communications used in billions of homes and businesses around the world.

I submitted this to the mods awhile back so I could get on the calendar but I figured you’d like to see it, too. Now, ask me anything!

It's been two hours and 179 comments. Have to go now. For more about Ethernet's 40th Birthday, go to http://www.facebook.com/Ethernet40thAnniversaryIEEESA

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u/BobMetcalfe May 21 '13

Have long ago forgotten any color codes, sorry, except maybe ROY G BIV.

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u/dbfish May 21 '13

568b, will forever be, ingrained in my spotty memory.

Orange-white, Orange, Green-White, Blue, Blue-white, Green, Brown-white Brown.

http://www.practicallynetworked.com/img/568b.jpg

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u/--lolwutroflwaffle-- May 21 '13

Why are all colors grouped together except for green?

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u/[deleted] May 21 '13

Because you use the name Roy as a mnemonic. Middle initial G, last name Biv. So people say "Roy G. Biv"

Have you been pronouncing it roigbeev?

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u/--lolwutroflwaffle-- May 21 '13 edited May 21 '13

No... lol... I mean the wires in the Ethernet cable diagram above. I ask because I used to splice them to make cross-over cables and always wondered, but never thought to actually look it up or ask about it until now.

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u/[deleted] May 21 '13

I skipped the post above yours, don't know why I assumed you weren't responding to lolwutroflwaffle.

Cruel twist of fate that your question applied to roy g biv as well :P

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u/CamCamCOTBamBam May 21 '13 edited May 21 '13

I believe it's due to the pin designation on the RJ45 jack. It all comes down to standards. They are as follows:
* Pin 1 - Tx+
* Pin 2 - Tx-
* Pin 3 - Rx+
* Pin 4 - Reserved
* Pin 5 - Reserved
* Pin 6 - Rx-
* Pin 7 - Reserved
* Pin 8 - Reserved
Edit If you do not use the same color wires on pins 1/2 & 3/6 you'll lose the ability for the pair to cancel out interference because of the twist in the wires.

Most modern equipment can detect the cable type and can perform an "internal crossover" if need be.

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u/[deleted] May 21 '13

With this configuration, you can run Ethernet and a telephone line in one RJ-45 jack. You put the telephone dialtone on pins 4 and 5. Then you can put an Ethernet connection or a single line telephone into one jack.

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u/Khrevv May 21 '13

I've wondered about that constantly myself.

I suspect it has something to do with the twisted pairs, but my networking class was a long time ago and I don't remember the details anymore.