OPTO-4 is a marine serial interface cable designed to connect NMEA 0183 / RS-422 navigation equipment to a computer or other device with an RS-232 9-pin serial port. It provides optical isolation on the NMEA input to help protect connected equipment from electrical ground loops, with additional spike suppression for the PC output. The unit is powered through the RS-232 port’s handshaking lines in typical installations, simplifying connection without a separate power supply. It is suitable for marine navigation data interfacing, including GPS and other NMEA 0183 data sources.

Technical Specification

Specification	Details
Make	Ami
Model	OPTO-4
Part Number	A-OPTO-4
Product Name	NMEA 0183 Serial Opto Isolator
Equipment Type	Serial Data Interface / Opto-Isolator Cable
Primary Function	Connects NMEA 0183 / RS-422 equipment to an RS-232 serial port
Communication Standards	NMEA 0183, RS-422 and RS-232
Isolation	2 kV optical isolation on NMEA input
NMEA Input	1 isolated RS-422 input
NMEA Output	1 RS-232 output
Baud Rate	4,800–115,200 baud
NMEA Input Voltage	±15 V continuous maximum; ±35 V for less than 1 second
NMEA Input Signal Thresholds	Logic 0: +2 V to +15 V; Logic 1: −15 V to 0 V
RS-232 Host Voltage	±7 V to ±15 V
Output Voltage / Current	Depends on host RS-232 interface; typically ±7 V to ±15 V at up to 10 mA
Current Consumption	Approximately 2–5 mA, depending on RS-232 voltage
Power Supply	Normally powered through RS-232 RTS/DTR handshaking lines
PC Connector	9-pin female DB9
NMEA Wire Connections	Red: input A/+; Black: input B/−; White: output A/+; Blue: output B/−; Bare: shield
Cable Length	1.5 m
Cable Wire	22 AWG tinned stranded copper
Cable Outer Diameter	5.5 mm
Cable Jacket	PVC
Shielding	Internal foil shield
Housing	Black PVC over-moulded case
Operating Temperature	−20°C to +70°C
Electrical Standard	Meets IEC 61162-2
Weight	Approximately 100 g
Compliance	RoHS compliant; cable UL certification E137250
Manufacturer	Active Research Ltd. (Actisense)
Origin Country	United Kingdom