Icom M504 Instruction manual

©2011 Icom America Inc Page 1
Icom America, Inc.
12421 Willows Rd NE
Kirkland, WA 98034
Connecting a GPS to Your Icom M504/M504A radio
The back panel of your M504/A radio has 2 wires that you can use to connect to your
GPS.
M504 Connections
Radio
GPS
NMEA in + (red wire)→
NMEA / Data out
NMEA in

(red wire shield) →
NMEA / Data ground
NMEA out + (white wire) →
NMEA / Data in
NMEA out (white wire shield)
→
NMEA / Data ground
GPS Example Connections
You will need to solder the 2 wires and their shields to the NMEA wires from your
GPS. For more specific information, consult the individual instruction manual from
the GPS manufacturer.
Garmin GPS

©2011 Icom America Inc Page 2
Icom America, Inc.
12421 Willows Rd NE
Kirkland, WA 98034
Raymarine GPS
Note: When using some Raymarine equipment you may need to connect your Icom
radio directly to the Raymarine GPS itself, not through a repeated port from other
equipment, such as a plotter. This ensures that the proper NMEA sentence passes to
the radio.
Standard Horizon GPS

©2011 Icom America Inc Page 3
Icom America, Inc.
12421 Willows Rd NE
Kirkland, WA 98034
Troubleshooting Your GPS Connection
•Your Plotter/GPS receiver must be capable of sending the proper sentences
(listed below) set for NMEA 0183 (Check your Plotter/GPS instructions for
information.)
•Verify that the plotter/GPS device is sending GPRMC, GPGGA, GPVTG, GPGLL, or
GPGNS sentences. (Check Plotter/GPS Instructions.)
•If you are still not receiving latitude and longitude, you can try setting the plotter
to send one sentence at a time (if possible). This can help it find the most
compatible sentence.
•Have a technician check the plotter/GPS using test equipment to verify it is
sending the GPS sentence.
•Check the solder points on the radio and plotter connectors. Some connectors are
very small, increasing the likelihood of solder bridging.