In article <DAA7E8AD-EFFF-4076-85DB-1CDC19AFA483@cs.columbia.edu>, Steven Bellovin <smb@cs.columbia.edu> writes
Remember, it was this strange time when people were uncertain about how networks were going to evolve, and what the next thing would be, and even then, 10baseT was being deployed over Cat3 (sometimes recycled/ repurposed), so any sort of "enabling" gadget such as these cards had a tendency to be abused in various ways.
Right -- the wire and pin assignments for 10BaseT and 100BaseT were designed to permit sharing the cable between Ethernet and phone.
I wired a new-build house (of mine) like that in 1995. The CAT5 cable was expensive enough that it made sense to share. And it worked. The bigger challenge was getting Internet to the house, not round the house. Ten years later, both voice and data would probably have been better done by wireless (DECT and wifi respectively). -- Roland Perry