The parallel device operates like the other Amiga devices. To use it, you must first open the parallel device, then send I/O requests to it, and then close it when finished. See "Introduction to Amiga System Devices" chapter for general information on device usage. The I/O request used by the parallel device is called IOExtPar. struct IOExtPar { struct IOStdReq IOPar; ULONG io_PExtFlags; /* additional parallel flags */ UBYTE io_Status; /* status of parallel port and registers */ UBYTE io_ParFlags; /* parallel device flags */ struct IOPArray io_PTermArray; /* termination character array */ }; See the include file devices/parallel.h for the complete structure definition. Opening The Parallel Device Writing To The Parallel Device Reading From The Parallel Device Closing The Parallel Device