Actisense NMEA 0183 PC OPTO-Isolator Cable, RS232 DB9 Female, Shielded (Isolated to PC) [OPTO-4]NMEA 0183 PC OPTO Isolator Cable, RS232 DB9 Female, Shielded (Isolated to PC) Add isolation to an RS232 port to protect against ground loops. The OPTO 4 provides a safe and low cost way of connecting an RS422 (NMEA 0183) system to an RS232 (PC COM port) system, or any other device with a standard RS232 9 pin port. The OPTO 4 provides comprehensive galvanic OPTO isolation to protect the PC input receiver, plus important spike suppression to improve the