Explaining how to use the printer adapter to make the PC a tool for developing microprocessor applications, this text shows how to build a complete data acquisition system. Applications such as recording weather parameters and posting them to the World Wide Web are illustrated. Additional tools discussed include PC hardware, the Enhanced Parallel Port (EPP), the Extended Communications Port (ECP), interfacing Analog to Digital converters and vice versa. There is also an economic approach to interfacing with instruments through the parallel port.