Siemens SIMATIC Field PG P4 Manual page 134

Glossary
Interface Module
Module which controls and extends the hardware periphery.
IRQ
Acronym for interrupt request. One of a set of possible hardware interrupts,
identified by a number. The number of the IRQ determines which interrupt handler
will be used. In the AT bus, ISA, and EISA, 15 IRQs are available. Each device's
IRQ is hardwired or set by a jumper or DIP switch.
ISA
Industrial Standard Architecture (bus for expansion modules)
K
Keyboard
A keyboard is the collection of keys which are used to input data, text, characters,
letters, numbers, special characters, and control commands in a computer. The
keyboard forms the input interface between the user and the computer.
L
LCD
Liquid Crystal Display. Display type on the base of liquid crystals with a thin film
polarized molecular structure, enclosed between two transparent electrodes.
LED
Light Emitting Diode (for example, status display). Semiconductor diode that
transforms electrical energy into light.
License Key
The license key is the electronic key for a license. Siemens AG issues license
keys for software that is legally protected by license.
LPT1 Port
The LPT1 port (Centronics port) is a parallel interface that can be used to connect
a printer.
Glossary-8
SIMATIC Field PG P4 Manual
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