National Instruments GPIB-COM - Manual (Page 21)

© National Instruments Corporation 3-1 GPIB-COM User Manual
Section Three
Function Description
This section contains a block diagram of the GPIB-COM, followed by a description of each of its
functional components.
The GPIB-COM Interface
The GPIB-COM is a completely transparent interface between GPIB devices and any IBM PC
software that uses serial ports. A set of I/O registers identical to those on the standard IBM serial
adapter is used. On the GPIB side, the GPIB-COM includes a limited subset of interface
functions that address a GPIB device to listen when the computer sends data to the serial port and
to talk when the computer is waiting to receive data from the serial port. In order to be able to
respond immediately to commands and data sent to the serial port, the GPIB-COM must be the
GPIB System Controller and cannot work with other Controllers present.