Y1-03-0174 Rev. A Draft12SECTION 7 - GPSI/O Frequently Asked QuestionQ. How do I download position data from my GPS to my beacon?A. You must have a NMEA 0183 version 1.5 or higher output ready GPS unit and a GPS interface cable.The NMEA 0183 optical interface connector supplied with your TerraFix must be connected to theGPS interface cable using a universal serial adapter. Turn on your GPS unit and allow it to acquirethe necessary satellites. Make sure the output is set to NMEA 0183 with the GGA sentenceconfigured if necessary. Connect the NMEA 0183 interface cable to the GPS unit and the TerraFix.The TerraFix will initiate a data preload when the GPS I/O button is pressed for more than ½ secondand less than 5 seconds.Q. How long does it take to down load position coordinates from my GPS to my beacon?A. Upon connection with a properly operating and fully acquired GPS unit, the ACR beacon usuallytake less than four minutes to synchronize and download coordinates. Subsequent position updateswill take from a few seconds to no more than 20 seconds to complete.Q. How does the GPS data get from my GPS to the beacon?A. The GPS unit transmits data as electrical energy through the GPS interface cable to the ACR opticalinterfacing connector. The ACR optical interfacing connector has an infrared LED and sensor locatedin it. The electrical energy supplied by the GPS unit is converted to infrared light in the ACR opticalinterfacing plug. Data from the GPS unit is transmitted via infrared light to the beacon through thetranslucent beacon top cap or lens when the ACR optical interface plug is properly engaged. Thebeacon has an infrared detector that decodes the light pulses. ACR uses an optical interface design toeliminate the potential for leaks and corrosion common to mechanically interfacing devices. An externalLED flashes to confirm that GPS data is being sent from the handheld GPS.Q. Does my beacon need any special set up to accept GPS data?A. No. If it is hooked to a valid data source, that has been properly set up to deliver NMEA format with theGPGGA sentence, it will automatically attempt to download the data and form an emergency messagethat includes the position data when the preload function is initiated.Q. Does my GPS unit have to be set up in a special way to transmit position coordinates via theNMEA 0183 interface?A. For the GPS to transmit data, go to GPS setup and make sure the NMEA 0183 output is turned on andthe GGA NMEA sentence is selected or turned on. Consult your GPS user’s manual for information onconfiguring the NMEA output.Q. What is the maximum length my GPS cable can be?A. ACR Electronics recommends a maximum length of 400 feet using 24 AWG wire. Contact your GPSowner’s manual for more detailed information.