39• TEXT OUT - allows simple ASCII text output of location and velocity information, withoutany input capabilities.• RTCM IN - allows DGPS input using a standard RTCM SC-104 format without any outputcapabilities.• RTCM/NMEA- allows DGPS input using a standard RTCM SC-104 format and supportsthe output of standard NMEA 0183 version 3.0 data.• RTCM/TEXT- allows DGPS input using a standard RTCM SC-104 format and simple ASCIItext output of location and velocity information.• NONE - Provides no interfacing capabilities.If ‘GARMIN DGPS’ or ‘RTCM/NMEA’ format is selected, additional fields are provided tocontrol a Garmin differential beacon receiver (e.g. GBR 21) directly from your eTrex. You canenter the beacon frequency and bit rate when you select ‘User’ from the Beacon pop-up list tomanually tune the receiver (you can also ‘scan’ if you don’t know what the nearby station is,but the unit could continue scanning if reception is temporarily lost).To select an I/O Format:1. Press the PAGE button to switch to the MENU Page. Press the UP and DOWN button andhighlight the ‘SETUP’ field. Press ENTER. The SETUP Page appears.2. Press the UP or DOWN button to select the ‘INTERFACE’ field. Press ENTER. The INTER-FACE Page appears.3. Press ENTER on the ‘I/O FORMAT’ field. Press the UP or DOWN button to select thedesired format. Press ENTER. Press PAGE to return to the page of your choice.The interface options will allow you to use a PC todownload waypoints, routes, and Track Logs.NMEA stands for “National Marine ElectronicsAssociation” and RTCM stands for “Radio Techni-cal Commission for Maritime Services.” Both areinvolved in developing technical standards for themarine electronics industry.Setup PageInterface Page