FDDI over unshielded twisted pairs

Experiments aimed at transmitting 62.5 Mb/s nonreturn-to-zero data stream over 24 AWG PVC unshielded twisted pair are described. Data transmission is performed over a 100-m cable with two active interfering pairs with data retiming using recovered clock. The transmission system is based on modified duobinary modulation. A solution is presented to one of the problems which must be solved in order to send fiber distributed data interface (FDDI) signals over unshielded twisted pairs. The results indicate that FDDI may operate on this medium given a suitable mechanism for multiplexing the full data rate between two separate signal paths. The multiplexing circuitry represents an area where additional study is needed.<
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