The Model 542B Fiberoptic Transceiver was the world's first repeating, multi-drop, fiberoptic RS-232 modem. This transceiver is specifically designed for multi-drop SCADA systems applications. The unit has built-in repeater and resynchronizing circuitry that is configurable for different baud rates from 300 to 19,200 baud. At 1200 baud, the delay per transceiver is 8.0 milliseconds (a bit time of 1.6 ms). Delay is approximately linear with bit time. At 300 baud, transceiver delay is 32 ms and at 19,200 baud it is 0.5 ms.
The Model 542B features: