Most tone arms have either two RCA outputs or a DIN output. Most of the TT cables that I see have either RCA plugs on both ends or DIN on the TT end and RCA on the pre-amp end. (Plus a ground, of course).
Why don't you see "Balanced" or "XLR" connections on the pre-amp end? I suppose it has something to do with cartridges being unbalanced, but I'm not certain. Does anyone know for certain why this is the case?