Serial Communication Adaptor

• RS232 to RS485
   

RS-232 side

• Connector: DB-9 female
• Signals:
  • Passes through pins 3 (TD) and 2 (RD)
  • Pins 7 (RTS) and 8 (CTS) are tied together
  • Pins 4 (DTR), 6 (DSR) and 1 (CD) are tied together
     

RS-485 side

• Connector: 4-pin terminal block
• Signals:
  • Half-duplex two-Wire operation only
  • Automatic control circuit enables driver only when transmitting
  • Receiver is disabled when transmitting to prevent echo back to RS-232 device
  • Can transmit up to 4000 feet at 19200 baud.
     

Power Requirements

• At least two RS-232 handshake lines, derives power from hosts serial port