Quick Facts Acts as repeaters, isolators, and extenders. T Isolates the TD, RD, RTS, and CTS channels, supports 115.2-kbps speeds on all four channels, and extends the RS-232 signal beyond 50 feet (15.2 m). Further Details Protect equipment from ground loops and spikes while optically isolating it from the rest of a network and expanding a system beyond node or distance limits.