Many hand held GPS receivers deliver time information accurate to within 3 to 70 milliseconds via a serial cable which can be connected to your PC's RS-232 serial port. Many GPS clocks advertise accuracy to within the nanosecond range. PresenTense Server supports both hand held GPS receivers as well as GPS clocks that communicate via the NMEA 0183 protocol. The benefits of hand held GPS receivers are cost effectiveness and availability - they may be purchased at many outdoor outfitters and office supply stores in every major city. Depending on the construction of the building in which you intend to operate your time server and GPS receiver, you might require an external antenna for your GPS to guarantee availability of satellite signals. See Recommended Parts List  |