I know that gigabit ethernet needs to use all four pairs of wires. The idea is that POTS is such low frequency that I believe it should be possible to separate it from the gigabit signal using a filter.
Is there any other technical problem that makes it difficult? e.g. The effect of a filter on gigabit signal timing (I'm just making this up. I don't actually know much about how ethernet signaling works.)
Best Answer
Encode the telephone signal, assign it to a VLAN, send it across with the rest of the data, as data, pick off the VLAN, decode the signal. Any other route is madness. (If doing POTS at all. VoIP obviously solves it at a higher level.)