Digital I/O The circuits use an 82C55A PPI with mode 0 supported. Ports A, B, C High, and C Low are buffered with 74ABT245 transceivers and pulled up to 5V. COS Detection Change of State Detection allows the card to generate an interrupt, port by port. Either direction will set the change of state interrupt. Your application can run much smoother by using this feature as processor overhead is greatly reduced, polling is not required. Counter/Timers The optional 82C54 has three-sixteen bit counters within one chip. These counters are useful for making frequency outputs, measuring frequency of square waves, pulse width outputs, pulse width measurements etc. The 104-DIO-48S is supported in most operating systems and include a free DOS, Linux and Windows 95/98/Me/NT/2000/XP/2003 compatible software package. This includes sample programs and source code in "C" and Pascal for DOS, and Visual Basic, Delphi, C++ Builder, and Visual C++ for Windows. Also included is a graphical setup program in Windows.