Knowledge Base

Can I use the NMEA Opto-isolator for other non-NMEA uses?

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Yes. The NMEA Opto-isolator adapter has been specifically designed to work as an isolator for the NMEA system. However, it can also be used in most systems that use the RS422 or RS485 (4-wire) connection protocols.

The Opto-isolated adapter cable utilises a full Galvanic Opto-isolated input circuit to protect the RS232 / PC’s receiver and a TransZorb diode to protect the RS232 / PC’s transmitter.

This adapter cable also converts the RS422 / RS485 (NMEA) voltage levels to RS232 (PC) voltage levels, and vice-versa.

As an example of alternative uses, by using two adapters at each end of a cable (back-to-back), the normal maximum RS232 cable length of 20 metres can be extended up to and beyond 100 metres.

In the RS232 / PC receive direction, it provides complete isolation of expensive RS232 / computer hardware when connecting to an NMEA 0183 bus link that may have picked up potentially hazardous voltages around the electrically noisy environment of a boat.

In the RS232 / PC transmit direction, a TransZorb diode provides a high level of static spike protection, but does not offer the complete protection of an opto-isolator and so is only recommended for connection to equipment with Opto-isolated inputs.