The GPS 18x units by Garmin are fully compatible NMEA GPS antennas that connect to your PC. The 18x PC is a small puck style antenna, at 61mm in diameter and it is WAAS enabled. The serial version will connect to a DB9 or serial port on your PC and will power from the 12 volt lighter with just about 7' of cable. The USB version also has 7' of cable and will connect to a USB port on your PC obtaining power from the laptop, through the USB port. The GPS 18 will work with most NMEA 0183 GPS software.
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