utp - What is the reason for T568A and T568B termination? - Network . . . A signal carrying pair cannot shield another signal carrying pair That's not how EM works Especially since they are a TX and RX pair, which are by definition uncorrelated signals The shielding argument is an old misunderstanding, as in my answer, the signals are planned pos-neg-pos-neg for preventing positive signal coupling, but this can be achieved with and without wrapping
layer1 - What do the positive and negative (+ -) transmit and receive . . . Two ways to go as I see, use the fiber to transmit the analog UTP signal or to transmit the digital data after decoding it from the UTP signal You could convert the analog signal from the UTP to transmit over fiber via whatever scheme you're interested and then just pump that signal back into UTP on the other side