Model 245 - RS-232 to RS-422/RS-485 Optically Isolated Interface Converter - 24 Volts

The Model 245 RS-232 to RS-422/RS-485 Optically Isolated Interface Converter is an optically isolated version of the Model 285. When operating as an RS-232 to RS-422 interface converter, the Model 245 converts full duplex data, TD and RD, between RS-232 and RS-422.When operating in RS-485, Model 245 has an "intelligent" mode which provides control of the RS-485 line. The Model 245 controls its transmitter data flow in two ways, the use of RTS, pin 4 of the RS-232 port, or turning it on when TD data is applied to the RS-232 port. In the 2-wire mode when no data is received by the RS-232 receiver, the RS-485 receiver is switched ON. When data is detected for transmission the receiver is switched OFF. In the 4-wire mode the RS-485 receiver is constantly ON while the transmitter is switched as required. The Model 245 has an eight-position dip switch that is used to select the following: RS-422 mode - 4 wire RS-485 mode - 2 wire or 4 wire RS-485 mode - controlled by the RTS, DTR or data 220-Ohm terminator A DTE/DCE switch reverses pins 2 and 3 of the RS-232 interface. TD and RD LED's on each side of the optical barrier help verify operation. Both ports of the Model 245 are implemented with DB-25 connectors; a male for RS-232 and female for RS-422/RS-485. Power is by 24 volts DC.