Can I use the OPTO-4 when the RS232 port does not provide power on the handshaking lines?

Yes, but you will need to provide power to the 9 pin connector (DB9) independently. Instructions for this are explained in the Quick Start Guide on the OPTO-4 downloads page.

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/