The Humminbird 688ci HD DI Combo is one of the new 600 series fish finders. It shares many similarities with the 788ci HD DI Combo, but it’s considerably cheaper.
This unit has a 5-inch vertical layout screen, 480 x 640 pixel resolution, with a backlit, 256 color display (TFT). As its name suggests, its a High Definition fish finder, even though it’s a smaller unit, and does provide crystal clear images.
In terms of sonar capabilities, the 688ci HD DI Combo is equipped with the standard Dual Beam Plus sonar which has two operating modes: 20° / 200 kHz, 60° / 83 kHz. This fishfinder also features Down Imaging technology, and to provide crystal clear images in Down Imaging, a beam of 455 kHz frequency is used. This makes it capable of scanning waters up to 350 ft. deep in Down Imaging, and up to 600 ft. with the regular sonar.
The wattage of this unit is 500 Watts RMS / 4000 Watts PTP, and the unit’s transducer is the standard XNT 9 DI T.
Regarding the unit’s GPS and navigational capabilities, the 688ci HD DI Combo includes a built-in Precision GPS, trackplotting and chartplotting, with the UniMap cartography package. It’s also compatible with the Lakemaster and Navionics Gold / HotMaps, but these are optional. It does not support Navionics Platinum+, C-Map or 360 Imaging. This unit is capable of storing up to 2,750 waypoints, 45 routes, and 50 / 20,000 tracks / points.
Other functions and features that this fish finder comes with are the Fish ID+, SwitchFire Sonar, Sonar Recording and ScreenShot functions, PC Connection, Temperature and Temperature Alarm, X-Press Menu System, MMC Compartment and 1 MMC slot.
