Garmin Fishfinder 250 Owner's Manual page 14

Installation
Wiring and Interfacing
You can download a copy of Garmin's proprietary
communication protocol document from the Support
section of our web site at www.garmin.com.
Complete information concerning
National Marine Electronics Association
(NMEA) format and sentences is avail-
able for purchase from NMEA at:
NMEA
Seven Riggs Avenue
Severna Park, MD 21146
U.S.A.
410-975-9425
410-975-9450 FAX
www.nmea.org
6
(TX COM 1)
To Unit
Note: During a typical installation, only the Red and
Black wires are used. The other wires do not have to
be connected for normal operation of the unit.
Interfacing
The Fishfi nder 250/250C allows for NMEA 0183, Version 2.3 input/output with a compatible GPS or
navigation device. NMEA Input/Output must be set to 'On' to send/receive data (see pg. 20). For additional
information on using your Fishfi nder 250/250C with NMEA devices, see pages 5, 15, and 20.
The following are the sentences for NMEA 0183, version 2.3:
Input — GPBOD, GPBWC (only used if RMB not present), GPGGA, GPGLL (only used if GGA not present),
GPRMB, GPRMC, GPXTE (only used if RMB not present)
Output — SDDBT, SDDPT, SDMTW, SDVHW, SDWPL* (only if a waypoint is "marked" in Pointer Mode)
*Garmin GPS units will accept the SDWPL (WPL) NMEA sentence and create a waypoint (saved location) at that position (see
pg. 15). For compatibility with other brands of GPS or NMEA capable navigation devices, check with that manufacturer to see if their
unit accepts/stores NMEA 0183 SDWPL sentences/waypoints. The Fishfi nder 250/250C does not store the actual waypoint. Only the
receiving device, if capable, will store the waypoint.
(TX COM 2)
(RX COM 2) (red) + 10-35 VDC
(RX COM 1)
(black) - Ground (Power/Data)
(blue) Port 1 Data OUT
(brown) Port 1 Data IN
(white) Port 2 Data IN (N/C)
(green) Port 2 Data OUT
(yellow) Alarm Low
Alarm Relay
100ma max
coil current
To Transducer
Power
10-35 volts
RXD + GPS/NMEA
Device
TXD +
and RXD -
NMEA Device
RXD +