Glossary
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A slot on either a CPU or Expansion I/O Backplane to which a Link Unit can
be mounted. Backplanes differ in the slots to which Link Units can be
mounted.
A system that includes one or more of the following systems: Remote I/O
System, PC Link System, Host Link System, or Net Link System.
Any of the Units used to connect a PC to a Link System. These are Remote
I/O Units, I/O Link Units, PC Link Units, Host Link Units, and Net Link Units.
n a Link System connected through Branching Link Adapters, the communi-
cations cable that runs from the Unit at each end of the System through the
Link Adapters.
A PC Link System in which at least one PC has two PC Link Units mounted
to it.
A PC Link System in which more than two PCs share a common data area.
Disturbances in signals caused by electrical noise.
In a Wired Remote I/O System, an optical cable connecting two Converting
Link Adapters. Specified because the System otherwise uses wire communi-
cations.
A communications method in which signals are sent over optical fiber cable
to prevent noise interference and increase transmission distance.
Cable made from light conducting filaments used to transmit signals.
An acronym for Programmable Controller.
All of the PCs that share the same part of the LR are in a PC Link System.
PC Link Subsystems exist within a PC Link System when one or more of the
PCs in the System has two PC Link Units mounted to it. If Subsystems exist,
the System is considered a Multilevel PC Link System.
A System in which PCs are connected through PC Link Units to enable them
to share common data areas, i.e., each of the PCs writes to certain words in
the LR area and receives the data of the words written by all other PC Link
Units connected in series with it.
The Unit used to connect PCs in a PC Link System.
With building-block PCs, all of the Racks and independent Units connected
directly to them up to, but not including the I/O devices. The limits of the PC
System on the upper end is the PC and the program in its CPU and on the
lower end, I/O Units, Special I/O Units, Optical I/O Units, Remote Terminals,
etc.
Devices connected to a PC System to aid in system operation. Peripheral
devices include printers, programming devices, external storage media, etc.
Any of the Units in a PC Lin system that share common data areas except for
the Polling Unit.
linkable slot
Link System
Link Unit
main line
Multilevel PC Link System
Multilink PC Link System
noise interference
optical cable link
optical communications
optical fiber cable
PC
PC Link Subsystem
PC Link System
PC Link Unit
PC System
peripheral device
polled unit