Just a CAT5 network jack

[btfdev]

We have all seen them on a daily basis. On the wall, wiring closet and inside data centers. We have plugged network cable into it. Knocking cable out of it when running across the room. The question is ... why not open up a CAT5 jack to see whats inside?

http://www.binarytaskforce.com/photoview-id-Q0FUNWUsRFNDXzA2MTIuSlBH

Upon tear down. WOW. Who would have thought a CAT5 jack PCB can be this complicated?!

http://www.binarytaskforce.com/photoview-id-Q0FUNWUsRFNDXzA2MTkuSlBH

See the bottom of PCB

http://www.binarytaskforce.com/photoview-id-Q0FUNWUsRFNDXzA2MjYuSlBH

Full album is here

http://www.binarytaskforce.com/photocontact-album-26

Cheers, Team BTF

[Marco]

Interesting, so is all the capacitance to compensate for the inductance of the wire connectors and the untwisted parts of the wires?

[crispy_tofu]

Wow that's pretty cool, thanks for sharing! 

[SeanB]

Most is to get the length of all the traces to the same length, so that the signal is not delayed too much differentially so the receive side cannnot decode reliably. Another reason is to keep impedances matched, even with the discontinuity introduced by the punch down blocks.

[Marco]

It is all interdigitation and not meander. When I said compensate I did mean try to get back to the 100 Ohm transmission line impedance disturbed by the more inductive impedance of the untwisted wires and connectors, it's only 100 MHz so you can separate the inductance and capacitance a bit to form a transmission line.

[SeanB]

there is some compensation for length by having the green pair coming off the connector at the front, and it is connected at the front punch block as well, so the length is somewhat matched. The small capacitor are there to make a LC to match the PCB to the cable better.