Is there bi-directional isolation with the Opto-4?

No, only the RS232 (PC) input is isolated from the NMEA 0183 Talker. An NMEA 0183 Listener connected to the RS232 (PC) output must have an isolated input. For bi-directional isolation, two OPTO-4 cables can be connected back to back.

For more information on NMEA 0183 and how it works, please download our free guide to NMEA 0183 networking here: https://actisense.com/everything-to-know-about-nmea-0183-guide/