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Everyone, hello!

So I'm building a PCB in my head right now, and I just wanted to quickly eliminate a thought I had in my mind.

When I add a RJ45 jack connector to my PCB board, there are (depending on how the connector is build, of course (with LED or not, etc)) normally 8 PINs for the 8 wires in the cat5/6 cable.

I put together this quick picture: enter image description here

Is this correct? Do the numbers on the RJ45 jack connector correspond with those on my cat wire?

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    \$\begingroup\$ Probably. But the best way to eliminate all doubts is to check the datasheet of this specific jack part. \$\endgroup\$ – dim Dec 8 '16 at 15:25
  • \$\begingroup\$ Looks like a regular jack without magnetics, why just not check it with DMM? \$\endgroup\$ – Flanker Dec 8 '16 at 15:29
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    \$\begingroup\$ The datasheet will tell you, some with magnetics might in rare cases have slightly different layouts \$\endgroup\$ – PlasmaHH Dec 8 '16 at 15:32
  • \$\begingroup\$ @dim it mentions on the documentation: "POSITION 1 INSERT TYPICAL" through "POSITION 8 INSERT TYPICAL", that doesn't really help me though, does it? \$\endgroup\$ – user5740843 Dec 8 '16 at 15:42
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    \$\begingroup\$ If the datasheet does not clearly state the pinout, you should either bin the part and buy a part with a half-decent datasheet, or meter it out. \$\endgroup\$ – uint128_t Dec 8 '16 at 15:48
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Is this correct? Do the numbers on the RJ45 jack connector correspond with those on my cat wire?

Not necessarily. You have to use datasheet for the connector, and create device in your EDA tool as per datasheet with proper symbol and package.

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I found myself asking this exact question at work this week after encountering an RJ45 connector with a somewhat different PCB-side pin-out than what I was expecting (I was expecting something along the lines of what the original poster suggests in their jack diagram).

Digging a little deeper, I found there are two common PCB-side pin-out configurations. This datasheet from TE Connectivity labels them as "traditional" and "Category 5": 5558341-1 Datasheet

Similarly, browsing through entries in the tables in this catalog document indicates a mix of pin-outs out there: TE Connectivity modular jacks catalog

As other people have suggested, definitely check the datasheet for the specific part you intend to use. I realize this answer comes long after the original question was posted, but hopefully it helps someone else avoid the moment of excitement I experienced during a PCB layout review yesterday afternoon.

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Your first problem is that you have labeled the plug contrary to convention; precisely backwards.

enter image description here

Your second problem is that pins out of the jack don't always correspond directly to the pins inside the jack, so you need to check the datasheet and or with a multimeter.

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