This 2006 design is commercially
sold, the circuit is provided here


RS232 to RS485 Converter

RS232 to RS485 Converter specification

  • Data (vs RTS) controlled - does not rely on PC handshake timing
  • TxD and RxD translated from RS232 to RS485
  • DB25 RS232 connector compatible with PC
  • Direction of transmission controlled by Data
  • Handshake loop the PC connection so it works with all software
  • RS485 signals output on D9 male with lots of Ground pins
  • Indicator LED(s) to show communications traffic
  • Line powered - powered by RS232 handshake lines
  • RS485 Termination resistor not included
  • Baud rate is dipswitch selectable 1200 - 115.2k
  • Pullup/Pulldown resistors on RS485 to establish line-idle condition
  • $256 Australian 2-49pc
  • $99 Australian 50pc and up
  • Manufacturing Rights to the design (including source code) available for the cost of 50 units

Our new model of RS485 converter overcomes the RTS controlled problem experienced by our free design. However, to do that requires a microprocessor, so there is a greater complexity to the design. We sell this unit, although currently we are limiting our sales to customers who can pay by bank transfer - which in reality is local Australian companies. This design has been relatively trouble free, and if you require quantities we can adapt the connector pinout to suit your application - however then the device will no longer fit the simple little D25 case in which you see it pictured.

Our 232 to 485 converter

The RS232 to RS485 converter

Circuit - 232 to 485 converter

The RS485 converter circuit diagram

©2013 AirBorn - Last updated 23 April 2013