Port-Powered RS-232 to RS-422 Converter

  • Extend RS-232 data signals up to 1.2 km (4,000 ft.)
  • Converts RS-232 TD and RD to balanced RS-422 signals
  • Baud rates up to 115.2 kbps
  • Powered from RS-232 handshake lines - no power supply required
Model 422LP25R, RS-232 to RS-422 converter, converts unbalanced RS-232 signals to balanced RS-422 signals. The power used for this converter is derived from the Transmit Data line (pin 2) and the Handshake Control Lines (pins 4, 5, 6, 8, and 20). The converter can derive power from these lines when they are in the Positive or Negative voltage state. This permits the converter to be used in applications without regard to software control of the handshake lines. If no handshake lines are available and all power must be derived from the Transmit Data line, the converter can drive limited cable lengths. A guide for this condition would be to drive only several hundred feet of transmission line and not to terminate the transmission line with a resistor of less than 1000 Ohms. When more handshake lines are available, longer lengths of cable can be driven. This converter has been tested at 115.2k baud with 1220 meters (4000 feet) of cable.