MA-49 Rack Mount RS-485 Converter
The MA-49 is used for conversion between RS-422/485 and RS-232/V.24 signals. This device is often used in multidrop applications mounted in the Westermo RV-01 rack system. In 2-wire half duplex transmission (RS-485) the direction of the bus is controlled by handshaking signals. In 4-wire mode the RTS line is used to tri-state the transmitter when other connected devices are transmitting data. Transmission rates up to 115.2 kbit/s are possible and the unit meets the RS-422/485 standard allowing up to 32 nodes over a total distance of 1 200 metres.


  • Conversion between RS-232/V.24
  • Suitable for 2- and 4 wire systems
  • DIP switch selectable fail-safe and termination circuit
  • Total galvanic isolation
  • Protects connected units from lightning/ transients
  • Completely data transparent
  • Bus state controlled by RTS
  • Use to connect equipment on different earth potentials
  • Guarantees reliable long-distance communication

MA-49 Diagram