General Interface Concepts; Definition - HP 9000 Series 300 Tutorials Manual

General Interface Concepts
The remainder of this chapter discusses interfaces in general and the HP-IB
and GPIO interfaces in particular. This background information is helpful
for understanding system operation, but is not prerequisite to being able to
successfully use DIL routines.
Definition
An interface is a built-in or plug-in electronic subassembly that manages the
transfer of information between the computer and one or more peripheral
devices. It converts electrical signals from the computer to a form that is
compatible with the requirements of the peripheral device and converts signals
from the peripheral device to a form that can be used by the computer. The
interface also controls information transfer paths and transfer timing such that
data flows in an orderly manner in correct sequence.
HP 9000 computers are equipped with both built-in as well as plug-in
interfaces that can be purchased as standard or optional items. Separate
interface cabling connects the peripheral device( s) to the interface unless the
peripheral device is built into the computer housing. The following functional
block diagram illustrates the functional architecture of a typical interface:
Computer
I/O
Backplane
Connector
Electrical I/O
Level Conversion Device
Circuitry Connector
Interface Logic
and Peripheral
Control Circuitry Device
Figure 1-1. Interface Functional Diagram
Interfacing Concepts 1-5