Electronic – Interface two Ethernet (10 Base) devices without 4 twisted pairs cable (Common ethernet cable) and 10 Base-T Filter

ethernetfilterinterconnectNetworknetwork-interface

I'm autumn and recently working on a project that wants to connect two IC with part: ENC28J60 (that connects microcontrollers (with SPI interface) to Ethernet and LAN Networks) directly in a PCB board (witouth cables and only with cupper tracks in my PCB.

As you know for connecting ENC28J60 (or any 10mbps LAN device) we need a 1:1 filter (it used for CMRR increasing) and you can find lots of schematic for that in google.

for the Ethernet cable (4 twisted pairs cable) we connect the TPIN+, TPIN-, TPOUT+ , TPOUT- pins of ENC28J60 to 10 Base-T Filter and then Connect Ethernet Cable to otherside of the filter. it's common and simple.

But the Question is: How can i connect two 10Base Ethernet Device (Like ENC28J60) without filters in short distance? (like a small PCB) (short distance will not cause noise and we don't need any filter for CMRR and twisted pairs).

Thanks,

Best Regards.

Best Answer

Try this application note from Micrel. It's their app note, so they promote their devices that they've tested it with, but I'd be very surprised if it doesn't work on pretty much any Ethernet PHY - they're all interoperable.

edit: The app note tells you exactly how to wire two PHY's back to back, including if one or both of them are "current mode", or "designed to interface to a transformer".