Preliminaries on Latching Low Level Physical Signals from a parallel port of a PC

Abstract

In this study, a practical approach is viewed to capture low level physical signals, which are in form of TTL (Transistor-Transistor-Logic) signals, from a standard parallel port of a personal computer, PC. Both hardware and software consideration is taken into account. An appropriate hardware design to latch TTL signal out of the PC, is proposed. High level programming language commands as well as operating system commands are mentioned in context with programming issues.