TABLE OF CONTENTS Parallel transfer of digital data (including measurement data) offers much higher data rates than serial data transfer. Two factors contribute to this transfer step-up. One is simultaneous transfer of information in the form of 4-bit (in Centronics standard) to 32-bit (in VXI standard) words. The other factor refers to the fact that parallel data transfer avoids some routines necessary in serial transfer, such as error check and correction procedures used in dividing the bit stream into words [1, 2]. Parallel interface can be used in measurement systems arranged within a limited area (10 m 2 to 100 m 2, typically). Larger areas involve longer multiwire (at least 24-wire) cables, which is disadvantageous for cost-effectiveness reasons, and additionally involves some technical problems due to the RLC parameters of such cable, and its wave properties at transfer rates in the order of 100 KBps or more. Parallel transfer can be carried out through wired channel only.
There are several parallel interface standards, the dominant one being ANSI/IEEE-488 (ANSI is the acronym for American National Standard Institute). Developed by Hewlett-Packard under the name of HPIB (Hewlett-Packard Interface Bus), IEEE-488 is also known as IEC-625 (international standard). The generic name of IEEE-488 is GPIB (General Purpose Interface Bus). IEEE-488 is the first interface standard developed exclusively for measurement systems. The IEEE-488 interface is designed to interconnect measurement system components such as digital instruments, other electronic devices (e.g., generators, power supply units, and...
