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Humminbird 688ci HD Combo

Humminbird 688ci HD Combo
688ci HD Combo Sonar and GPS from Humminbird
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5"DualBeam Plus1500'Internal,

The 600 series from Humminbird was launched in 2014. It includes several, pretty decent fish finders, all of them with HD, color display. Most of the units also include GPS and trackplotting, and the 688ci HD Combo is one of them.

Even though it does not have any superior sonar features, this unit still has a lot to offer in terms of fish finding and navigational features.

Features and Specs

  • Screen: 5″ diagonal, 480H x 640V pixel resolution, color TFT, with backlight
  • Sonar: DualBeam Plus with SwitchFire
  • Depth Capability: 1500 feet (457 m)
  • Frequency and Coverage: 200 kHz / 20° and 83 kHz / 60°
  • Transducer: Transom XNT 9 20 T
  • Power Output: 500 Watts (RMS)
  • Power Input: 10-20 VDC
  • GPS: Internal, Precision, Speed
  • Maps: UniMap
  • Routes, Waypoints, Tracks: 45, 2,500, 50 (20,000 points each)

One of the most important aspects to be mentioned about the 688ci HD Combo is that the box includes the transducer for it, so you do not have to purchase one additionally. However, the included transducer is transom-type. Therefore, in case you need a through-hull one or a transducer for a trolling motor, you’ll have to pay extra for one. The included XNT 9 20 T transducer also has a water temperature sensor already built in.

The unit is IP67 protected, meaning that it’s dust-tight and submersible at 1 meter, for up to 30 minutes.

The sonar capabilities of this unit are rather basic. It does have DualBeam Plus sonar, which allows you to view both transducer returns on screen, blended in the same image, or in split screen. This unit has quite a fair depth capability. It works at depths up to 1,500 ft (457 m), with a target separation of 2.5 inches (6.35 cm).

Like most Humminbird units, the 688ci HD Combo also includes SwitchFire mode. This function allows you to quickly control the view of the sonar returns. It has two settings: Clear Mode and Max Mode. Clear mode quickly filters the unwanted clutter, focusing on fish size accuracy. Max Mode gives you the maximum, raw sonar information caught by the transducer beams, for more fish arches and better jig tracking.

Along with SwitchFire, this fish finder offers several other sonar functions. Selective FishID+ and the Ice Flasher view are two of them. The fishID function analyzes the sonar returns in a different manner, and if a return meets a specific array of parameters (characteristic to a fish), that particular return will be displayed on the screen with a fish symbol. There are 3 fish icon sizes: small, medium and large. Therefore via this function, you can get a better idea of how big a certain fish caught by the sonar is.

As the terminology suggests, the ice flasher function is useful for ice fishing, or down-dropping. It’s a much simpler function for tracking your lure, track depth and observe the fish coming in contact with your lure.

One of the best features of the 688ci HD Combo from Humminbird is the sonar recording. This function gives you the possibility to record the sonar return for a specific area and review it later. However, to be available, this function requires an SD card to be inserted in the SD card slot of the unit. The recorded data is saved on that particular card. The SnapShot function of the unit, which basically allows you to save a desired sonar or map view, also requires an SD card. Other useful functions for the sonar reading of this unit are Freeze Frame, Mark Structure, Temperature, and Fish Alarm.

The Humminbird 688ci HD Combo is equipped with a 50-channel built-in Precision GPS/WAAS receiver, providing fast satellite acquisition, and location accuracy up to 2.5 meters. Speed is also measured via the unit’s GPS. Also, this unit includes the UniMap cartography pack, which covers the contiguous U.S. coastline, inland lakes, and rivers at 30 meters per pixel resolution.

Upgrade Possibilities

First of all, the unit’s software is upgradable. Second of all, since it does have a microSD card slot, you can upgrade the mapping of the unit with several packages, such as Navionics Gold and HotMaps and Humminbird Mapping.

The mounting system of the head unit is also upgradable. The box includes a quick disconnect mounting system, but there’s also an in-dash mounting kit available. Also, the transducer mounting system can be replaced with one compatible for a trolling motor, in case you have one.

What’s Best About This Unit

On the pluses list of the Humminbird 688ci HD Combo, there can be mentioned quite several of its capabilities that many other fish finders with GPS simply don’t have. First of all, this unit offers a Dual Beam Plus sonar, which not only gives you the possibility to scan the water column under your boat in two modes, you can have both views blended on the screen into one image, or view them in split screen.

The unit offers high-definition imaging. Even if you won’t benefit from Side Imaging, Down Imaging or CHIRP sonar, you will still get the best quality imaging on both sonar and maps.

Sonar recording is also quite a plus. This feature gives you the possibility to have a second, better look at the underwater environment, structure, and fish, and select the best fishing spot, without having to follow the same route several times.

The transducer is included with the unit, just as for most units from Humminbird. Therefore, you won’t have to bother ordering it.

The waypoints, routes, and tracks are great functions to have, which many other units either from Humminbird or other manufacturers, don’t have. Marking the best fishing spots on the map, or recording your course is a great plus.


The display of the unit has a vertical layout, which gives less screen surface horizontally, for split screen. However, in case you don’t like this type of display layout, you can always have a look at the HELIX 5 GPS from Humminbird.


The Humminbird 688ci HD Combo is a unit that comes with a fair price/quality/capability ratio. It offers the basic fish finding and navigational functions that any angler needs on the water. It’s not one of the top fish finders out there, but it gets the job done in helping you locate the best fishing spots, and accurately telling your your position. It’s a unit worth every penny.

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