Nah, you're thinking of a Transceiver, that was yet another intermediate interface. Old ethernet interfaces had a Mac chip, a phy chip to the DB15 connector, and then a tranceiver chip off in a box that would talk to other things. I don't think that the MII interface used between the MAC and PHY can be coerced into a transceiver interface, can it (10base2) ? That'd be sorta neat; I still have some 10baseT transceivers lying around.