LAN
Local Area Network. An interconnection of devices in which data is transferred without the use of public communications services. Modbus Plus is an example of a LAN for controlling and monitoring industrial processes.
layer
In the OSI Model, a portion of the structure of a device which provides defined services for the transferring of information. See Data Link Layer and Physical Layer.
LLC
Logical Link Control. The part of the device that performs the protocols for identifying users of the network and for providing reliable frame delivery. The LLC handles the framing and checking of messages.
MAC
Medium (or Media) Access Control. The part of the device that performs the protocols for sharing the network with other devices. The MAC handles the queueing and transmission of outgoing LLC level messages, address recognition for incoming messages, and resolution of access contentions.
MAP
Manufacturing Automation Protocol. A network protocol that allows devices or cells within an industrial environment to communicate with each other.
master
A networked device which controls other devices to which it connects. It initiates transactions, and schedules and transmits tasks to a slave device. See slave.
medium
The entire cable system: the network cable, taps, connectors, and terminators.
Modbus
An industrial networking system that uses RS232 serial
Modbus Plus
An industrial networking system that uses
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