Displaying Sonar Images on a GPSMAP 172

To display a Sonar image on a GPSMAP 172, you will need to purchase and connect two items. The first item is a remote sounder box. You can use either of the two discontinued sounder boxes, the GSD 20 or GSD 21.

The second item you will need is a transducer. To find a compatible transducer, please visit the webpage for the remote sounder box that will be connected to the GPSMAP 172. From this webpage, click on the Accessories tab and then choose Transducers.

The Installation Manual for the remote sounder box will provide a diagram that shows how to connect the GPSMAP 172 to the sounder box. The transducer will then plug directly into the sounder box.

Once everything is connected correctly, you will need to change a setting in the GPSMAP 172. Please follow these directions to change this setting:

1. With the device powered ON, press the Menu button twice
2. Highlight the Comm tab on the left side of the screen
3. Press the Right arrow once to highlight the Port 1 tab at the top of the screen if you used the Blue and Brown wire of the GPSMAP 172c to connect to the sounder box
   1. If the Green and White wires were used to connect the GPSMAP 172c to the sounder box, press the Right arrow button one more time to highlight the tab called Port 2
4. Press the Down arrow one time
5. Press the Enter button
6. Highlight Garmin Remote Sonar
7. Press the Enter button

Once all of the above steps are done, the device should now be able to display a Sonar image.