Industrial Remote I/O

I am looking for a suitable technology to serialize and deserialize signals from an FPGA in an industrial environment.  The goal is to combine many outputs from an FPGA onto a single Cat 5/6 cable and then reproduce those signals at the remote location and combine many inputs at the remote location at the FPGA.  

Requirements:

1. > 4 signals per twisted pair
2. Individual signals are < 100 kHz but need < 500 ns jitter.
3. Cat 6 cables STP
4. Up to 50 m length