Nmea 0183 Connection Considerations; Lamp Or Horn Connections; Video Input And Output Considerations - Garmin GPSMAP 7400 Series Installation Instructions Manual

The port labeled NMEA 2000 is used to connect the device to a
standard NMEA 2000 network.
Item Description
NMEA 2000 compatible Garmin device
GPS antenna
Ignition or in-line switch
NMEA 2000 power cable
NMEA 2000 drop cable
12 Vdc power source
NMEA 2000 terminator or backbone cable
NMEA 2000 T-connector
NMEA 2000 terminator or backbone cable

NMEA 0183 Connection Considerations

• See the installation instructions for the NMEA 0183 device to
identify the transmit (Tx) A (+) and B (-) wires and receive
(Rx) A (+) and B (-) wires.
• Each internal Rx and Tx port has 2 wires, labeled A (+) and B
(-) according to the NMEA 0183 convention. The
corresponding A (+) and B (-) wires of each internal port
should be connected to the A (+) and B (-) wires of the NMEA
0183 device. See the table and wiring diagrams when
connecting the data cable to NMEA 0183 devices.
• You must use 28 AWG, shielded, twisted-pair wiring for
extended runs of wire. Solder all connections and seal them
with heat-shrink tubing.
• See NMEA 0183 Information, page 6
approved NMEA 0183 sentences that are output by and input
to your device.
• The internal NMEA 0183 ports and communication protocols
are configured on the connected Garmin device. See the
NMEA 0183 section of the chartplotter owner's manual for
more information.
• The ground wires on the NMEA 0183 data cable and your
NMEA 0183 device must both be connected to ground.
• When connecting NMEA 0183 devices with two transmitting
and two receiving wires, it is not necessary for the NMEA
0183 devices to connect to a common ground.
• When connecting a NMEA 0183 device with only one
transmitting (Tx) wire or with only one receiving (Rx) wire, the
NMEA 0183 devices must be connected to a common
ground.
• For two-way communication with a NMEA 0183 device, the
internal ports on the NMEA 0183 data cable are not linked.
For example, if the input of the NMEA 0183 device is
connected to the internal output port 1 on the data cable, you
can connect the output port of your NMEA 0183 device to
any of the internal input ports (port 1, port 2, port 3, or port 4)
on the wiring harness.
4
for a list of the
• There are four internal NMEA 0183 input ports (Rx ports),
and two internal NMEA 0183 output (Tx ports) on the
included NMEA 0183 data cable. You can connect one
NMEA 0183 device per internal Rx port to input data to your
Garmin device, and you can connect up to three NMEA 0183
devices in parallel to each internal Tx port to receive data
output by your Garmin device.
NMEA 0183 Connection Diagram
Item Description
12 Vdc power source
Wiring harness
NMEA 0183 compliant device
Item Garmin Wire Garmin Wire
Function Color
Power Red
Ground Black
Tx/Rx
Tx Blue
Rx Brown

Lamp or Horn Connections

The device can be used with a lamp, a horn, or both, to sound or
flash an alert when the chartplotter displays a message. This is
optional, and the alarm wire is not necessary for the device to
function normally. When connecting the device to a lamp or
horn, observe these considerations.
• The alarm circuit switches to a low-voltage state when the
alarm sounds.
• The maximum current is 100 mA, and a relay is needed to
limit the current from the chartplotter to 100 mA.
• To manually toggle visual and audible alerts, you can install
single-pole, single-throw switches.
Item Description
Power source
Power cable
Horn
Lamp
Relay (100 mA coil current)
Toggle switches to enable and disable lamp or horn alerts
Item Wire Color
Red
Black
Yellow

Video Input and Output Considerations

This device allows video input from composite video sources
and video output to a monitor, depending on the model. When
-
+
NMEA 0183 Device Wire
Function
Power
Data ground
Tx/Rx/B (-)
Rx/A (+)
Tx/A (+)
Wire Function
Power
Ground
Alarm