GPS Time and Test is a PC Clock synchronization program. The program synchronizes a PC Clock to the right time using artificial satellites. It is alternative solution to synchronizing with atomic clock using NTP(SNTP) and Internet. The program works in the interactive mode or in background. It uses NMEA protocol. $GPZDA, $ZQZDA or $GPRMC protocol sentences are explored as time source. The program can be used as NMEA and COM port tester. It outputs a port receiving buffer, extracts all NMEA sentences and counts check sum errors. Default protocol version is NMEA 0183. If you want to use this program you need a GPS (Global Positioning System) unit connecting to PC's COM port.