09/25/02 GPS_field_guide 8:19 A9/P9133.2 Utilisation of the eTrex unitThis section presents the major elements that will be used in the context of the WHO WHS.It introduces you to the basic features of the eTrex as well as some basic definitions ofterms in a more detailed way than presented on the Quick Reference guide.3.2.1 Installation of the batteriesTo install the batteries, remove the battery cover (Figure 10) by turning the D-ring at theback of the receiver 1/4 turn counter-clockwise. Insert the batteries into position observingproper polarity. Attach the battery cover by turning the D-ring 1/4 turn clockwise.Important Battery Installation Information:Warning : Improper installation may cause damage and/or battery leakage.Be sure to observe the proper polarity when inserting the batteries:It is very important to install the TWO batteries with the proper polarity, positive (+) andnegative (-) orientation as indicated in the unit's battery compartment and in the QuickReference Guide.Remove the batteries from your eTrex if you don't expect to use it for several months.3.2.2 The eTrex operating systemIn order for the user to read information and setup the unit, theeTrex receiver contains an operating system. To access this system,hold the unit so the built-in antenna (the flat area above the display)is parallel to the ground, the screen facing upwards. Press and holdthe POWER Button firmly to turn on the unit.The 'WELCOME' page (Figure 11) is then displayed on the screenwhile the unit conducts a self test.Once testing is complete this page will be replaced by the'NORMAL SKYVIEW SATELLITE' which represents the firstelement of the operating system.Figure 11 -The Welcome page