Three components are required in order to produce a computer interface:
The computer allows information to flow back and forth between the computer and peripherals through the parallel port. The interface such as printer consists of electronic components that require commands to be operated. The peripherals allow commands to be sent to the interface, and one most common example is parallel port.
The main peripheral that can be used in a computer is a parallel port, where pins 2-9 are outputs that send signals to external devices, pins 10-13 and 15 are input pins that receive signals from external devices, and pins 18-25 are ground pins. Such peripheral allows you to construct an interface between a printer or scanner and a computer. It can also allow you to construct an interface between sensory devices and a computer. Thus, the common parallel port can be used for several interface system between computer and interface.
The software controls functioning of the interface system. The parallel interface, mouse, and graphical user interface must be controlled by the software. The interface software sends appropriate commands to signal such activities as printing, turning LED on and off, or starting or stopping a motor. Mouse software is required to allow the user to input information and control the interface such as the printer. Graphical User Interface consists of clickable boxes, and visual representation of the peripherals operation is helpful visuals that can allow the user to determine the progress of the operation. In summary, this software is necessary for control over the interface.
Parallel port can be used to interface:
LEDs - turn on or off, display a pattern
Motors - starting or stopping, controlling further operations
Sensory devices - such as miniature robots
Printer - executing printing instructions
Scanner - executing scanning...