GARMIN20.TXT INTERFACING THE GPS-20 TO APRS Document version: 8.3.5 10 Mar 99 Author(s): Bob Bruninga, WB4APR ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The GPS-20 is an OEM GPS circuit card which only needs three wires and an antenna to work. Connect Ground, +5 volts (regulated) and Serial data output to your PC, TNC, or other RS-232 serial device. It will power up and begin sending data immediately. -------------------------- | GPS-20 CARD | | *-|---< pin 10 +5 volts | *-|---> pin 4 TXD to serial port | | | *-|---* pin 8 GROUND (common) -------------------------- ANTENNA: Just scale any favorite antenna to 1575 MHZ (1.8" quarter wave). CAUTION: The antenna jack has +5 volts on the center pin, Dont short it! NOTES: 1) It will take the card up to 20 minutes to get its FIRST ever fix. From then on, it should take only a minute or two.. 2) The 5 volt power supply must be stiff (low impedance). Otherwise, the GPS may not initialize on power up. 3) If you want to run both a TNC and the GPS on the same COMM port with APRS, see the GPS.txt file. 4) The GPS-20 comes with a complete tech manual. But also see GPS.TXT de WB4APR