Garmin GPS III Plus Manual

The Garmin GPS III Plus is a rugged, waterproof handheld GPS receiver featuring a high-contrast display, built-in worldwide basemap, external antenna capability, 12 parallel channel GPS receiver, TracBack® feature to retrace your path, 500 waypoints with graphic symbols, 20 reversible routes, and user-selectable map datums. It operates on 4 AA batteries and includes a PC interface cable. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation & Power 3. First-Time Setup 4. Specifications 5. Controls and Display 6. Connecting to External Devices 7. Basic Navigation Operations 8. Advanced Features 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: High-contrast LCD display, Power/Backlight key, Page key, Rocker keypad, Enter/Mark key, Zoom In/Out keys, external antenna port, PC interface port.

Feature	Description
12-Channel GPS Receiver	Fast acquisition and reacquisition, tracks up to 12 satellites
Built-in Worldwide Basemap	Includes cities, highways, borders, and water features
TracBack® Feature	Reverses your route to guide you back to your starting point
500 Waypoints	Store and name locations with graphic symbols
20 Reversible Routes	Plan and follow complex routes
External Antenna Port	For optional external antenna for improved reception
PC Interface	Connect to a computer for data transfer and software updates
Waterproof Design	Meets IEC 529 IPX7 standards (submersible in 1 meter of water for 30 minutes)
Backlit Display	For use in low-light conditions
Track Log	Automatically records your path for later review

Installation & Power

Unpack and inspect contents. Install batteries for first use.

Install Batteries: Open battery compartment on back, insert 4 AA batteries observing polarity.
External Power (Optional): Can use optional 12V DC adapter for vehicle or AC use.
Attach Wrist Strap: For secure handling.
Acquire Satellite Signal: Power on unit and take outdoors with clear view of sky for initial fix.

WARNING! Use only recommended batteries. Do not mix old and new batteries or different types.

First-Time Setup

Power on GPS; follow initialization prompts.

Select Language: Use the rocker key to highlight language, press ENTER.
Set Time Format: Choose 12-hour or 24-hour format.
Set Units: Select statute (miles/feet) or metric (kilometers/meters).
Initialize GPS: Allow unit to acquire satellite signals (may take several minutes first time).
Set Position Format: Choose coordinate system (Lat/Lon, UTM, etc.) and map datum (WGS 84 default).

CAUTION! For best initial satellite acquisition, be outdoors away from tall buildings and trees.

Specifications

Receiver: 12 parallel channel GPS receiver.
Update Rate: 1 second continuous.
Accuracy: <15 meters RMS.
Dynamics: Supports speeds up to 999 knots.
Interface: NMEA 0183, RTCM 104 DGPS, and proprietary GARMIN.
Display: 5.2 x 3.8 cm (2.0" x 1.5") high-contrast LCD, 120 x 160 pixels.
Waypoints: 500 with names and graphic symbols.
Routes: 20 reversible routes with up to 50 waypoints each.
Track Log: 1024 points with trackback.
Power: 4 AA batteries (alkaline or NiMH), 12-16 hours typical use.
Waterproof: IEC 529 IPX7 standard.
Operating Temp: -15°C to 70°C (5°F to 158°F).
Dimensions: 5.4 x 14.9 x 3.2 cm (2.1" x 5.9" x 1.3").
Weight: 255 g (9 oz) with batteries.

Controls and Display

Access functions via dedicated keys and page sequences. Front Panel: POWER (also controls backlight), PAGE, ROCKER (up/down/left/right), ENTER/MARK, ZOOM IN, ZOOM OUT.

Display Pages: Use PAGE key to cycle through: Satellite Status, Map, Navigation, Highway, and Main Menu.

Satellite Page: Shows satellite positions, signal strength, and estimated position accuracy.

Map Page: Displays your position on the basemap, waypoints, and track. Use ZOOM keys to change scale.

Navigation Page: Shows bearing, distance, and time to destination.

Highway Page: Provides a compass-like display for course guidance.

Main Menu: Access to waypoints, routes, track log, setup, and system functions.

Connecting to External Devices

External Antenna: Use optional GA 27C or similar via external antenna port. PC Connection: Use PC interface cable (optional) to transfer data or update software.

Turn off GPS before connecting cables.
For PC connection, install GARMIN MapSource software (optional purchase).
Select appropriate interface format (NMEA or GARMIN) in System Setup if needed.

Tip: Ensure connections are secure and ports are free of debris.

Basic Navigation Operations

Creating and navigating to waypoints, following routes.

Mark Your Position: Press and hold ENTER/MARK key. Edit name/symbol if desired, press ENTER to save.
Go To a Waypoint: From Map page or via Main Menu > Waypoints, select waypoint, choose "Go To".
Follow a Route: Main Menu > Routes. Select route, choose "Navigate".
Use TracBack®: Main Menu > Tracks > TracBack. Select saved track to reverse.
Zoom on Map: Use ZOOM IN/OUT keys to change map scale.
Pan on Map: Use ROCKER key to move map cursor to view surrounding area.

WARNING! GPS is a navigation aid. Always use in conjunction with maps, compass, and local knowledge.

Advanced Features

Simulator Mode: Practice navigation indoors (Setup > System > Simulator > On). Proximity Waypoints: Get alerts when within a set distance of a waypoint. Sun/Moon Information: View sunrise/sunset and moon phase data for any date/location. Area Calculation: Calculate the area of a polygon you walk around.

Care & Maintenance

Clean with a soft, damp cloth. Do not use harsh chemicals or abrasives. Periodically check battery compartment for corrosion. Store in a cool, dry place.

CAUTION! Do not expose to extreme temperatures for prolonged periods. The unit is waterproof but ensure port covers are securely closed.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits. This device complies with part 15 of the FCC Rules. Operation is subject to the condition that this device does not cause harmful interference. Copyright © Garmin Ltd. or its subsidiaries. Garmin and the Garmin logo are trademarks of Garmin Ltd. or its subsidiaries. For support, visit www.garmin.com or contact Garmin Product Support.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Unit will not turn on	Dead batteries, improper installation	Install fresh batteries; check polarity.
No satellite acquisition	Obstructed view, indoors	Move to open area with clear sky view; ensure unit is stationary during initial fix.
Inaccurate position	Poor satellite geometry, multipath	Wait for better satellite alignment; move away from tall buildings/reflective surfaces.
Display is dim or blank	Backlight off, contrast setting	Press POWER to adjust backlight; adjust contrast in Setup > Display.
Waypoint/Route data lost	Batteries removed for extended period	Internal memory backup lasts only a few minutes without batteries. Save data to PC regularly.
PC interface not working	Wrong cable, incorrect settings	Use correct GARMIN interface cable; verify interface format in System Setup matches PC software.

Reset: If unit locks up, remove batteries for 30 seconds, then reinstall.

Service: Contact Garmin Product Support or visit www.garmin.com.