What are the Advantages of GPS Navigation?
For centuries, man has been searching for an accurate method of navigating the world. From celestial navigating to loran and SatNav, each system has had its problems with weather, range and reliability. GPS helps you get more out of your outdoor recreation by providing accurate position and course information, anywhere in the world, regardless of the weather or your proximity to physical geographic features. The accuracy and coverage of GPS navigation can help make any outdoor navigation safer, smarter and more efficient, wherever you may travel.

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1. A constellation of satellites transmit signals to earth, containing precise position and time information for each satellite. 2. Your GPS unit searches for these signals, and locks on to as many as eight satellite signals for continuous tracking. 3. Once the receiver is locked onto a set of signals, it can determine how far away each satellite is by measuring the time it takes to receive each signal. By knowing the distance and position of 3 or more satellites, the GPS receiver can then calculate your position by using a technique called satellite ranging. This calculation, or triangulation, simply measures your position in reference to a set of known objects (the GPS satellites). 4. As the GPS receiver tracks satellites, it will continuously update your position and provide track and speed information while youre moving.

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Basic Denitions
The GPS 40 is a powerful navigation tool that can guide you anywhere in the world. To better understand its operation and capabilities, it may be helpful to review the basic terms and concepts briey explained below.
Navigation is the process of traveling from one place to another and knowing where you are in relation to your desired course. Position is an exact, unique location based on a geographic coordinate system. Most recreational navigation is based on the latitude/longitude system. Meridians of longitude are a set of imaginary circles around the earth that pass through the north and south poles. Longitude describes position in terms of how many degrees it is east or west of the Prime Meridian (0 longitude). Parallels of latitude are another set of imaginary circles that are perpendicular to the earths polar axis. Latitude describes position in terms of how many degrees it is north or south of the equator (0 latitude). A waypoint marks an exact position x so it can be recalled for future use. The GPS 40 lets you mark waypoints electronically, without physical landmarks. Bearing is a compass direction to a particular destination (waypoint) from your present position. Track is a compass direction representing your course over ground.

The graphic compass display is designed to show your current track and does not serve as a true magnetic compass while youre standing still.
The sky view will help you determine if a satellite signal is being blocked by buildings, mountains or other obstructions. As satellites are locked onto, the sky view indicators will change from a reverse-video highlight to a standard display. If you encounter difficulty acquiring satellite signals, try facing another direction or walk towards a clearer view of the horizon.
The rest of the page shows your current position in three dimensions: latitude, longitude and altitude. The GPS 40 uses this basic information to mark exact positions as waypoints, which help guide you from one place to another.

Position Page

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Marking a Position

Getting to know your new GPS is as easy as taking a quick stroll around an open outdoor area. To get the most out of this tutorial, make sure to walk for at least the time noted for each step. This way, youll reduce the chances of staying within the receivers margin of error. Youll also get a much better indication of the units visual guidance and mapping capabilities. Once youve acquired a position, mark it as a waypoint for future reference.
1. Press the M key to capture and hold your present position.
The Mark Position Page appears, showing the captured position and a default 3-digit waypoint name. Lets change the default name to something thats a little more meaningful.
1. Press theU key twice to move the eld highlight from the save eld to the name eld. 2. Press the E key to begin entry of your waypoint name. 3. Press and hold theU key to scroll through the alphabet until the letter H appears. 4. Press the R key once to move the character highlight to the next character space. 5. Repeat steps 3 and 4 until the word HOME is displayed. 6. Press E to complete entry of the name. 7. Press theD key once to return the eld highlight to the save eld. 8. Press the E key to conrm that you want to save the position as a waypoint named HOME.
The Mark Position Page will be replaced by the page displayed prior to pressing the M key.

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Now that youve marked a position, its time to take off on a brisk walk and put your GPS 40 through its paces.
1. Walk in a straight line for 2-3 minutes at a fast pace and watch the Position Page. You can time your distance with the on-screen clock.

The moving highway provides a visual perspective of the distance and direction to waypoint. The highway will always move to point in the general direction of your destination, with the relative distance indicated by the angle of the outside lines of the highway. 10
As you head towards your destination, the middle section of the screen provides visual guidance to your waypoint on a moving graphic highway. The moving arrow just below the course deviation scale always points to your selected waypoint (HOME) relative to the direction you are moving.

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Your present position is represented by the diamond in the center of the course deviation scale.

Steering Guidance

Destination Waypoint

Desired Track Line

Position Indicator Horizontal Finish Line

Pointer to Waypoint

The line down the middle of the highway represents your desired track. As you navigate toward a waypoint, the highway will actually move, indicating the direction youre off course, relative to the position diamond on the CDI scale. To keep your vessel on the desired course, simply steer toward the center of the highway. If you do get off the desired course by more than 1/5th of the selected CDI range, the exact distance you are off course will be displayed where the CDI scale setting normally appears (see the example at right). As you approach a waypoint, a horizontal nish line will move toward the bottom of the highway. When the nish line reaches the CDI scale, youve arrived at your destination. Whenever the GPS 40 has something it needs to tell you, a message indicator box will ash on screen. When you are less than one minute from reaching your HOME waypoint, the message box will begin ashing.
1. To view a message, press the P key when the message indicator appears. 2. Press P to return to the previous page.
In this example, you are off the desired course to the right by 0.19 miles. To get back on course. steer left to center the position diamond on the highway.
This example shows you are off the desired course to the left by 0.08 miles. To get back on course. steer right to center the position diamond on the highway. 11

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Page Sequence and Menus
Now that youve arrived HOME, scroll through the main pages of the GPS 40.
1. Press the P key to scroll through the ve main pages in sequence. 2. Press the Q key to scroll through pages in the opposite direction.
Use the Page and Quit keys to continuously scroll through the main pages in either direction.
The Menu Page allows you to view waypoint or route information and customize various functions of the GPS 40. To get a feel of how the Menu Page works, lets set the time of day for your location.

Use the left and right arrow keys to move the selected character eld and to move the eld highlight from eld to eld.
key changes the display to with G The GOTOhighlighted. Pressing GOTOthe Navigation PageMOB the waypoint eld twice activates the mode.
The POWER key turns the unit on and off and activates screen backlighting. To turn the unit off, press and hold the POWER key for 3 seconds.
you Q The QUIT key returnsvalue.to a previous page, or clears data entry, restoring a data elds previous The PAGE key scrolls through main P display from a submenu page to the data pages in sequenceItand returns the previous page viewed. also displays the message screen when a message alert appears.
The MARK key captures a position and displays the Mark Position Page.
ENTER key entry E The also activatesconrms dataelds toand on-screen responses. The ENTER key highlighted allow data entry.

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Satellite Status Page
Satellite Not Currently Tracked Satellite Numbers (1-32)
The GPS 40 Status Page displays the status of various receiver functions. The status information will help you understand what the GPS is doing at any given time. The sky view and signal strength bars give you an indication of what satellites are visible to the receiver, whether or not they are being tracked, and the signal quality. When a satellite is visible but not being tracked, the signal strength bar will remain blank and the sky view indicator will remain highlighted in reverse video.
If you are losing coverage or having trouble acquiring a position, use the sky view and signal strength bars to guide you towards a better location for GPS reception. If you have lost coverage and the unit has trouble reacquiring satellites, try shutting the unit off momentarily to reset the unit.
The satellite sky view shows a birds eye view of the position of each satellite relative to the receivers last known position. The outer circle represents the horizon (north up); the inner circle 45 above the horizon; and the center point a position directly over your head. Use the sky view to help determine if there are obstructions shading your reception of satellite signals.

Receiver status is indicated at the top left of the screen, with the current horizontal accuracy (in feet or meters) at the top right. The status will show one of the following conditions: Acquiring Satellites is the rst status youll see in normal operation. The GPS 40 is looking for satellites to track based on its last known position.

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2D Navigation status indicates that at least three satellites with good geometry have been locked onto and a 2 dimensional position x (latitude and longitude) is being calculated. 2D Diff will appear when you are receiving DGPS corrections in 2D mode. 3D Navigation indicates that at least four satellites with good geometry have been locked onto and your position is now being calculated in latitude, longitude and altitude. 3D Diff will appear when you are receiving DGPS corrections in 3D mode. Searching the Sky indicates that the GPS 40 is collecting new almanac data or AutoLocateTM mode has been selected (see page 38). This process can take 7.5 to 15 minutes. Poor GPS Coverage indicates that the receiver is no longer tracking enough satellites to provide a 2D or 3D position x. Simulating Navigation indicates that the receiver is in simulator mode. Below the receiver status eld and to the left of the satellite sky view is the battery level indicator.
The battery level indicator is calibrated for alkaline batteries. Ni-Cad and lithium batteries will not accurately display the battery level due to voltage differences. No other receiver functions are affected by using Ni-Cad or lithium batteries.
On the right side of the screen, just below the horizontal accuracy eld is the screen backlight indicator. When backlighting is on, a bulb icon will appear. To turn the screen backlighting on or off:
1. Press the B key. 2. To adjust the duration of screen backlighting, refer to the operation setup section (page 39). 16

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The GPS 40 Position Page displays your current positions latitude, longitude, altitude and time numerically. It also displays your track (compass direction) and speed whenever youre moving. The Position Page also lets you enter a positions latitude and longitude manually. During satellite acquisition, the position displayed is the last computed position stored in memory. If the receivers position has moved several hundred miles with the power off or memory has been lost due to battery failure, the unit may take 7 1/2 to 15 minutes to acquire satellite data. To speed up the acquisition process, you can enter a more accurate initial position. Most maps and charts show the latitude and longitude of major cities.

1. Press the D key until the position eld is highlighted. 2. Press E to begin entry of your position. 3 Use the L and R arrow keys to select the character position you want to edit. 4. Use the U and D arrow keys to select the value for each eld. All elds must have a value. 5. Press the E key to conrm your changes. The unit of measure for speed, position and altitude are all user-selectable. To change the default settings for these elds, refer to the navigation setup instructions on page 41.

Position Page Options

When the GPS 40 is acquiring satellites or navigating in the 2D mode, the last known altitude will be used to compute your position. If the altitude shown is off by several hundred feet, enter a corrected altitude manually for greater accuracy.
1. Press the D key until the altitude eld is highlighted. 2. Press E to begin entry of your altitude. 3. Use the U and D keys to enter a value in each character eld, using the L and R keys to move to the next character position. 4. Press the E key to conrm the altitude. 17

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Marking and Naming Waypoints
Knowing your present position is only part of any navigation equation. You also need to keep track of where youve been and where you are going. Waypoints serve as electronic markers that let you keep track of starting points, destinations, navaids and any other important position. The GPS 40 allows you to mark, store and use up to 250 waypoints. A waypoint position can be entered by taking an instant electronic x or by manually entering a coordinate or range and bearing in reference to an existing waypoint. To mark your present position (make sure you have acquired a satellite position) as a waypoint:
1. Press the M key to capture your position.
The Mark Position Page appears, showing the captured position and a default 3-digit waypoint name. To change the default position name :
1. Press the U key twice to move the eld highlight from the save eld to the name eld. 2. Press E key to begin entry of the name. Pressing the L key will clear any existing data. 3. Use the U and D keys to enter a value in the appropriate character eld, using the L and R keys to move to each character position. 4. Press E to conrm the waypoint name. The eld highlight will move to the route eld.
If youd like to add this waypoint to a route:
1. Press the E key. 2. Use the U or D keys to enter a route number. 3. Press the E key to conrm the route number. 4. Press the E key again to save the waypoint.

To return to the waypoint list page (when the done eld highlighted):
To delete all user dened waypoints:
1. Use the U or D keys to move the cursor highlight to the delete all waypoints eld. 2. Press the E key.
A warning page will appear, asking if you are sure you want to delete all user-dened waypoints and routes. If you want to continue and delete:
1. Press the L key to highlight the Yes eld. 2. Press the E key. 3. Press the Q key to return to the Menu Page.
If you do not want to delete all waypoints:
20 1. Press E with the no eld highlighted.

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The last of the three waypoint management pages is the waypoint denition page. This page lets you create new waypoints manually, as well as review and edit existing waypoints.
Waypoint Name Comment Field Rename and Delete Fields Position Coordinates Reference Waypoint Done Prompt returns the display to previous page

Waypoint Denition

To create a new waypoint manually, youll need to know its position coordinates or its distance and bearing from an existing waypoint. If you know the position coordinates for your new waypoint:
1. Press the D key to highlight the name eld. 2. Press E to begin entry of the waypoint name. 3. Use the U and D keys to enter your waypoint name, using the L and R keys to move to the next character position. 4. Press E to conrm the waypoint name. The position eld will now become highlighted, with the receivers last known position shown. 5. Press E to begin entry of the position. 6. Use the U and D keys to enter your position, using the L and R keys to move to each character eld. 7. Press the E key to conrm and save your coordinates. The default waypoint comment (UTC date and time of creation) will appear and the highlight will move to the done eld. 8. Press the E key to return to the Menu Page. 21

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Reference Waypoints
To create a new waypoint manually without knowing its position coordinates, youll need to enter its bearing and distance from an existing waypoint. The GPS 40 will then calculate the position coordinates for you.
Waypoint Name Reference Waypoint Bearing from Reference Waypoint Position Coordinates are calculated after entering reference data Distance from Reference Waypoint
1. Press D until the name eld is highlighted. 2. Press E to begin entry of the waypoint name. 3. Enter the name of your new waypoint. 4. Press the E key to conrm the waypoint name. The position eld will now become highlighted, with the receivers last known position shown. 5. Press the D key to move the cursor highlight to the reference eld. 6. Press E to begin entry of reference waypoint. 7. Use the U and D keys to enter the name of your reference waypoint, using the L and R keys to move to each character eld. 8. Press the E key to conrm your entry. 9. Enter the bearing and distance of your new waypoint from the reference waypoint. Remember to use the E key to begin entry and conrm each eld. The coordinates will be calculated and saved for your new waypoint. 22 10. Press the E key (when the done eld is highlighted) to return to the Menu Page.

1. Highlight the estimated time enroute (ETE) eld and press the E key. 2. Use the U or D keys to select DTK or ETA and press the E key.

Active Route Page

To invert a route from the Active Route Page:
1. Press the U key once to move the eld highlight to the invert eld. 2. Press the E key to invert the route.
To clear the active route from the Active Route Page and stop route navigation:
1. Use the U and L keys to select the clear eld. 2. Press the E key to clear the active route.
Once a route has been created and stored in the GPS 40, it can be edited at any time, even if it is the active route. To edit a route from the Active Route Page or the route submenu page:
1. Use the U and D keys to select the waypoint you want to edit and press E.
An on-screen menu of editing choices will appear, with options for reviewing, inserting, deleting or changing the waypoint eld highlighted. Use the U and D arrow keys to select among the editing choices.

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Editing Routes and On-Route GOTOs
Once youve selected a waypoint from the route list, choose a menu function:
1. To review the denition page for the waypoint, highlight the review eld and press E. 2. To add a new waypoint that precedes the selected waypoint, highlight the insert eld and press the E key. 3. To remove the selected waypoint, highlight the remove eld and press the E key. 4. To replace the selected waypoint with a new waypoint, highlight the change eld and press the E key.
Use the route waypoint editing instructions described earlier (see page 29) for creating a route to complete your changes. If you are editing the active route (route 0), copy your new route version to an empty route to save it, as the active route will be overwritten by a new route activation. If you add, delete or change the rst or last waypoint of a route, the default comment (rst and last waypoint) will automatically be updated after your changes. At the beginning of this section, we mentioned that the GPS 40 will automatically select the route leg closest to your position as the active leg. This will give you steering guidance to the desired track of the active leg. If you would prefer to steer directly to a route waypoint, you can perform an on-route GOTO from the active route page.

1. Use the U and D keys to highlight the desired route waypoint and press the G key. 2. Once the Navigation Page appears, press E to conrm the on-route GOTO waypoint.
Note that after you reach the on-route GOTO waypoint, the GPS 40 will automatically resume navigation of any previous route.

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The GPS 40 features a powerful moving map display that can do much more than just plot your course and route. The Map Page also provides you with a moving map cursor that will let you pan ahead to nearby waypoints, determine the distance and bearing to any map position and mark new waypoints while you navigate.
Zoom Control Field 8 x 10 Grid Scale (10 vertical) Bearing and Distance Fields Panning Control Field

Moving Map Page

Present Position Indicator

Track and Speed Fields

The Map Page can be broken down into three main sections: The zoom function and panning control elds are located at the top of the screen. There are 12 selectable zoom ranges from 0.2 to 320 miles or 0.5 to 600 km, measured vertically. The map portion of the page is bordered by an 8 x 10 grid to help you estimate distances based on the map scale you are using. Your present position is indicated by a position diamond, with your track and/or route displayed as a solid line. Nearby waypoints are represented as squares, with the waypoint name also listed. You may select which of these features are shown through the map setup submenu page (see page 43 for more information). The last elds directly below the map show your bearing and distance to one of three selectable destinations: an active destination waypoint; a highlighted on-screen waypoint; or to the panning target crosshair. Your current track and speed are displayed just below the bearing and distance elds.
The GPS 40 has onscreen range rings to help you estimate distances relative to your present position. The value of each ring is determined by the current zoom scale. The distance value of each ring is equal to 1/5th of the current zoom range, with the interval of each ring noted below the rst range ring. To turn the range ring display on or off (the default setting is off), see the map setup instructions on page 43.

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Moving Map: Zooming and Panning
There are three main functions you can perform from the Map Page zooming, pointing and panning. Each of these functions has its own eld, which may be selected and activated for use. Whenever the Map Page rst appears, the zoom eld (at the top left) is always selected. The Map Page has 12 map scales which are selected through the zoom function eld. To select a zoom scale:

Once a waypoint has been selected in the map eld, its distance and bearing from your present position will be displayed in the destination eld. You can also review its waypoint denition page or select it as a GOTO destination by following the same steps outlined above for waypoints highlighted on the map eld.

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Map Page: Advanced Zooming and Panning
One of the benets of a moving map display is being able to pan to different map areas and see whats out there. To get the most out of panning, youll need to be able to zoom in and out while youre panning. This lets you move the map at a faster speed and zoom in for waypoint details. Once the pan function is activated, the cursor highlight moves back to the zoom eld. To adjust the zoom range while panning:
1. Press the E key to begin range selection. 2. Use the U and D keys to select the desired zoom range. 3. Press E to return to normal panning mode.
During panning, the crosshair represents a target position right on the moving map, with the range and bearing to the target displayed at the bottom of the screen. You can also use the target crosshair to mark a new waypoint position or as a GOTO destination right from the map eld. To mark the target crosshair position as a new waypoint:
1. Press the M key to capture the position. 2. Enter a new name and route number if you wish. 3. Press the E key to return to the Map Page.
You can also use the target crosshair as an instant GOTO destination. Similar to the MOB mode, this function will mark and instantly set a course for a new waypoint called MAP. To GOTO the target crosshair:
1. Press the G key to capture the position. 2. Press the E key to conrm the MAP GOTO. 3. Press Q to return to the Map Page.
If you want to save the MAP waypoint, be sure to rename it, as it will be overwritten the next time a map GOTO is executed.

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The GPS 40 Menu Page provides access to submenu pages that are used to select and customize operation and navigation setup. The 11 submenus are divided into categories by function. The waypoint and route management submenus are discussed in their own respective sections. Well now address the rest of the submenus in the order they appear on the Menu Page. To select a submenu page from the Menu Page:
1. Highlight the submenu page you want to view. 2. Press the E key to display the submenu page. 3. To return to the Menu Page, press the P key.
Sun Calculation and Messages
The distance and sun calculation page will give you the distance and bearing between any two waypoints and calculate the sunrise and sunset (in local time) at a destination waypoint for a particular date. To perform a distance and sun calculation:

1. Move the eld highlight to the datum eld and press the E key. 2. Use the U and D keys to toggle through and select the desired setting. Conrm the setting by pressing the E key.

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The course deviation indicator (CDI) scale denition eld lets you select the +/- range of the CDI bar scale. Three scales are available: +/- 0.25, 1.25 and 5.0 miles or kilometers, with 0.25 being the default setting. To enter a CDI scale setting:
1. Highlight the CDI scale eld and press E. 2. Use the U and D keys to select the desired CDI scale setting. 3. Press the E key to conrm the selection.
CDI, Speed & Heading Setup
The GPS 40 lets you select statute (default), nautical or metric units of measure for all speed and distance elds. To change the unit of measure:
1. Highlight the units eld and press the E key. 2. Use the U and D keys to select the desired unit of measure. 3. Press the E key to conrm the selection.
The GPS 40s heading information can be displayed referencing magnetic north (automatic or user-dened), true north or calculated grid headings. The default setting is automatic magnetic north, which is suitable for most applications. To select a reference:
1. Highlight the heading eld and press E. 2. Use the U and D keys to select the desired heading preference. 3. Press the E key to conrm the selection.
To enter a magnetic heading:
. 1. Select the user mag heading and press E. 2. Use the U and D keys to enter the degrees and direction of magnetic variation. 3. Press the E key to conrm the magnetic variation value. 41

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Track Log and Map Setup

The track log setup page lets you manage the GPS 40s tracking data. From this page, you can select whether or not to record a track and dene how it is recorded. To turn the track log on or off:
1. Highlight the record track eld and press E. 2. Select yes or no and press E.
The stored track criteria determines how often positions are stored in the track log. The default setting is automatic, which stores track based on resolution. This setting gives you the most efficient use of track memory. To change the criteria to record points based upon a specic time interval:
1. Highlight the criteria eld and press E. 2. Use the U or D key to select time interval and press E. 3. Press E to begin entry of the interval. 4. Enter a value in hours, minutes and seconds in the eld and press the E key.
The rest of the track log setup page displays the percentage of available memory currently used to store track log data and a function eld to clear the track log memory. To clear the track log:
1. Highlight clear track log? and press E. 2. A warning page will appear, asking you to conrm your actions. Use the L key to move the eld highlight to the yes eld and press E.

Never store the GPS 40 without batteries. A built-in capacitor will save data while you are changing the batteries, but only for a limited period of time (a few hours). If youre storing the unit for an extended period of time, put in a fresh set of alkaline or lithium batteries. Storing the unit with Ni-Cad batteries may result in data loss due to the self-discharge characteristics of Ni-Cad of batteries.

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Appendix A

Glossary

Almanac DataSatellite constellation information (including location and health of satellites) that is transmitted to your receiver from every GPS satellite. Almanac data must be acquired before GPS navigation can begin. BearingThe compass direction from your position to a destination. Course Made Good (CMG)The bearing from the active from position (your starting point) to your present position. Crosstrack Error (XTE)The distance you are off a desired course in either direction. Desired Track (DTK)The compass course between the from and to waypoints. Differential GPS (DGPS)An extension of the GPS system that uses land-based radio beacons to transmit position corrections to GPS receivers. Estimated Time of Arrival (ETA)The time of day of your arrival at a destination. Estimated Time Enroute (ETE)The time left to your destination at your present speed. GridA coordinate system that projects the earth on a at surface, using square zones for position measurements. Ground SpeedThe velocity you are travelling relative to a ground position. LatitudeA north/south measurement of position perpendicular to the earths polar axis. LongitudeAn east/west measurement of position in relation to the Prime Meridian, an imaginary circle that passes through the north and south poles. PositionAn exact, unique location based on a geographic coordinate system. Track (TRK)The direction of movement relative to a ground position. Universal Transverse Mercator- (UTM) A grid coordinate system that projects global sections onto a at surface to measure position in specic zones. Velocity Made Good (VMG)The speed you are closing in on a destination along a desired course.

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Appendix B

Messages

The GPS 40 uses a ashing on-screen message indicator to alert you to important information. Whenever the message indicator appears, press the P key to view the message page. There are two types of messages: temporary alerts and condition alerts. Temporary alerts are cleared from the message page after viewing, while condition alerts remain on the message page until the condition has been resolved. Pay careful attention to all messages for your own safety. Accuracy has been DegradedThe accuracy of the GPS 40 has been degraded beyond 500 meters due to poor satellite geometry or data quality. You should check other navigational sources to verify the position indicated. Already ExistsThe waypoint name you are entering already exists in the GPS 40s memory. ApproachingYou are less than one minute away from reaching a destination waypoint. Battery Power is LowThe batteries are low and should be replaced. Cant change Active WPTYou have attempted to change the active to or active from waypoint. Clear the active route or GOTO before making your changes. No DGPS PositionNot enough data is being received to compute a DGPS position. No RTCM InputBeacon receiver is not properly connected or baud rates do not match. Poor GPS CoverageThe GPS 40 cannot acquire the necessary number of satellites to compute a position. Try moving to a location with a clearer view of the sky. Power Down and Re-initThe GPS 40 is not able to calculate a position due to abnormal satellite conditions. Turn the unit off and verify the last position shown by other means. Try the unit again later, possibly in a different location. Read Only Mem has FailedThe permanent memory has failed and the unit is not operable. Take your unit to an authorized GARMIN dealer for repairs. 49

O Offset, local time..38,51 Operating Mode Setup..38 Operation Setup..38,39 Output Setup..43-45 P Packing List..v Page Sequence...12 Panning...35,36 Position Entry..17 Position Page...17 Power Off...13 Power On..6 R Range Rings..33,43 Reference Waypoints...22 Relative Bearing Pointer..10,11 Resolution, track storing.42 Routes...27 Active Route Page..31 Creating and Copying..29 Clearing and Activating..30 Inverting Routes..30 Editing Routes..32 On-Route GOTOs...32 S Satellite Status...15,16 Satellite Status Page..15,16 Searching the Sky...16 Setup Pages..38-45 Simulator Mode..46
V Velocity Made Good (VMG)..10,48 W Waypoints..18 Waypoint Denition Page..21 Waypoint List Page..20 Nearest Waypoint Page..19 Marking Waypoints..18 Creating Waypoints..21 Naming Waypoints..18 Deleting Waypoints..24 Editing Waypoints..23 Renaming Waypoints.23 Welcome Page...6 Wiring Installation..55 Wrist Strap Attachment..58

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1994 GARMIN INTERNATIONAL 9875 Widmer Road, Lenexa, KS 66215, USA GARMIN/Europe Ltd Robert House, Station Approach Romsey, Hampshire SO51 8DU UK Part Number 190-00063-00 Rev. B

How to Construct a Cable for Garmin GPS receivers
Thank you for obtaining a connector for Garmin GPS receivers from us. This document will provide you with the information you need to construct virtually any type of cable you may require, whether you want to connect your GPS to a computer, two GPS units to each other, or to provide power to your GPS. Please remember that this information is provided without warranty of any kind. Though every effort is being made to ensure that the information is accurate, we cannot be held responsible for any errors or omissions. If you construct a cable that doesnt work (or even worse, damages your GPS, computer, or yourself) as a result of a mistake in these instructions, we would appreciate learning about the error so that it can be fixed, but we cannot be held liable for any damages.
Connector Pinouts and Signals
Diagrams represent the view of the connector as seen from the side that plugs into the computer or GPS. In other words, this is the side of the connector that you do NOT attach wires to. Keep this in mind when constructing your cable.
Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 7 Pin 8
DCD RxD TxD DTR GND RTS CTS

5 Male

A note about supplying power to your GPS
Some Garmin GPS receivers are capable of running off external power ranging up to +32VDC or more, whereas others can only accept a maximum of +8VDC. If your receiver can only accept 8 volts and you connect it directly to a car battery, you will damage your GPS (sometimes 18 volts or more can be present at the terminals of a 12 volt car battery, depending on its state of charge). If you want to build a cable providing power to such a receiver, you must incorporate a voltage regulator circuit to bring the voltage down to an acceptable level (the schematic diagram for such a circuit appears later in this document). Such a circuit isnt necessary if your receiver can deal directly with the voltage you are giving it. Were aware that the GPS-12, GPS-38, and GPS-40 receivers are limited to 8 volts, thus requiring a voltage regulator, and there may be others. Garmin provides a centre plastic pin on the connector of their GPSes which are limited to low input voltages. This enables a non-regulated power supply cable to be constructed which cannot be accidentally used on such receivers. But the safest thing is to check your user manual before supplying power to your GPS.
Female Carrier Detect Receive Data Transmit Data Data Terminal Ready Signal Ground Ready to Send Clear to Send
Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 7 Pin 8 Pin 20

13 Male 25 1

Assembling the Connector
The parts making up a Garmin-compatible GPS connector are shown in the exploded view below: Screw Cap Top Pins Base Plug
Female 14 Shield EMI Shield TxD Transmit Data RxD Receive Data RTS Ready to Send CTS Clear to Send GND Signal Ground DCD Carrier Detect DTR Data Terminal Ready

Mini Din-8

Note that the base section is oriented so that the side with the larger centre hole is to the right.
To assemble the connector, first insert the contact ends of the pins into the side of the base with the small centre hole. Then place the top over the pins so that it is flush with the base (the top and base together will hold the pins securely in place). Solder wires to the ends of the appropriate pins protruding into the top piece, ensuring that you dont let the pins get too hot, or the plastic connector may melt. You can then place the cap over the top and use the screw to hold everything together. If you are making an unregulated power supply cable, consider inserting the plug into the large centre hole in the base (its a friction fit). This will help to ensure that the cable you make is not accidentally used with a low voltage GPS receiver. If youre building a regulated circuit for a low voltage receiver that has a centre plastic pin, this plug must be left out. For specific details on how to construct a cable, please refer to the Connector Pinouts and Signals diagrams to the right, as well as the information on the following page.

Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8
HSKo Handshake Output HSKi Handshake Input TxD- Transmit Data SG Signal Ground RxD- Receive Data TxD+ Transmit Data + GPi General purpose Input RxD+ Receive Data +

GPS Connector

2 Female 4 Signal/Power Ground Transmit Data Power Receive Data

Gnd TxD V+ RxD

Constructing a Data Cable for the IBM with a DB-9 Serial Connector
First, determine whether or not you need a male or female DB-9 to plug into the serial port of your computer (most computers will require a female DB-9). Use the pinout diagrams on the preceding page for the DB-9 and GPS connectors, and connect the following pins: GPS Pin 4 (RxD) Pin 2 (TxD) Pin 1 (Gnd) DB-9 Pin 3 (TxD) Pin 2 (RxD) Pin 5 (Gnd)
GPS Pin 4 (RxD) Pin 2 (TxD) Pin 1 (Gnd)
Mini DIN-8 Pin 3 (TxD-) Pin 5 (RxD-) Pin 4 (Gnd)
If your GPS emits a true RS-232 signal (most dont), tie Pin 8 on the Mini DIN-8 to Pin 4 to ground it.
Incorporating a Power Source into your Cable
If your GPS is one of those capable of dealing with relatively high voltages, all you have to do is connect the positive supply to Pin 3 (V+) on the GPS connector, and the ground to Pin 1 (the same pin is used on Garmin receivers for both power and signal ground). If you have a receiver limited to lower voltages, youll have to incorporate a regulator circuit into your cable if you want to use your GPS with anything like a car battery (via a lighter adapter, for example). In either case, dont forget to add a fuse inline with the external power source. The following circuit will provide a steady output of 6VDC to a GPS receiver, which should work for most Garmin models (though as always, check with your manual to be sure of the maximum voltage tolerated by your receiver, and double check the output voltage before connecting it up).
Constructing a Data Cable for the IBM with a DB25 Serial Connector
First, determine whether or not you need a male or female DB-25 to plug into the serial port of your computer. Use the pinout diagrams on the preceding page for the DB-25 and GPS connectors, and connect the following pins: GPS Pin 4 (RxD) Pin 2 (TxD) Pin 1 (Gnd) DB-25 Pin 2 (TxD) Pin 3 (RxD) Pin 7 (Gnd)
Constructing a Data Cable to connect two Garmin GPS receivers
Obtain two GPS connectors and wire them as follows: GPS 1 Pin 4 (RxD) Pin 2 (TxD) Pin 1 (Gnd) GPS 2 Pin 2 (TxD) Pin 4 (RxD) Pin 1 (Gnd) 9-35V External Power Gnd + in
7806 out + 0.1F 1F Pin 3 (V+) GPS Pin 1 (Gnd)
Constructing a Data Cable for the Macintosh
The Macintosh serial port can deal with either RS-232 or RS422 signals, and uses the Mini DIN-8 connector. Wire the cable as follows:

In this circuit, 7806 is a 6V voltage regulator, and the values and types of capacitors are not critical. If you find your GPS still wants to run off its internal batteries with the external supply connected, chances are that it needs a bit more than 6VDC to trigger it into using the external supply. To fix this, try a voltage regulator with a bit higher outputjust dont exceed the maximum input voltage for your GPS.

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