Installation
Wiring and Interfacing
| (TX COM 2) |
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DC Positive |
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| (RX COM 2) | (red) + |
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(TX COM 1) | (RX COM 1) |
| Power |
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| (black) - Ground (Power/Data) |
You can download a copy of Garmin's proprietary communication protocol document from the Support section of our web site at www.garmin.com.
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.
(blue) Port 1 Data OUT |
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(brown) Port 1 Data IN | RXD + GPS/NMEA |
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(white) Port 2 Data IN (N/C) | TXD + |
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(green) Port 2 Data OUT |
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| and RXD - |
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(yellow) Alarm Low |
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| NMEA Device |
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Alarm Relay |
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| RXD + |
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100ma max |
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coil current |
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Complete information concerning
National Marine Electronics Association (NMEA) format and sentences is available for purchase from NMEA at:
NMEA
Seven Riggs Avenue
Severna Park, MD 21146
U.S.A.
www.nmea.org
6
Interfacing
The Fishfinder 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 Fishfinder 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 Fishfinder 250/250C does not store the actual waypoint. Only the receiving device, if capable, will store the waypoint.