New computers are now being made without serial ports. If you have a GPS cable which requires to connect to a serial port, and you have a compter which does not have a serial port, these USB serial adaptors will let you connect your cable to your PC. They allow connection of serial (RS232) siganal to a standard USB 2.0 port. They will also work with a USB 1.0 port, but you will not get a fast transfer rate.