I read int the cookbook section that its preferred to use a jack with transformers... I have a few of the punch down type jacks you'd put in a faceplate, and mount in a box... Like the jack on the wall in your office you plug your computer into. Does anyone know if this type of jack includes magnetics?? It's not apparent from looking at it..

Thanks Russ

These are just sockets for plugging in an ethernet cable that runs to your pc. The magnetics are only found on either end of an ethernet connection just before the ethernet receiver/transmitter device.

Ok Wim. Makes sense to me.

I was poking around and found an old HP Jet Direct print server here this evening. Looks like it has a jack with the built in link lights. I'm thinking I'll lift it off the circuit board and have a look at it. Hopefully this one will have the magic magnetics. I do read that they're not 100% required for experimentation, and I don't dabble in PoE, but I don't want to risk damage to my new mbed..

Thanks. I appreciate your reply.

Check the circuitboard arond the connector. External magnetics would be a rather large component (eg 1cm x 1cm x 1 cm) with maybe upto 12 pins. It should be located within 3 cm from the connector.