Installation guide

242 Glossary
890 USE 100 00
Bridge Plus
A Modicon device that interconnects two Modbus Plus networks.
broadband
A network communications method supporting multiple data
transmission channels, using frequency division multiplexing.
bus
An electrical channel used to send or receive data.
carrierband
A network communications method in which information is
transmitted using a single transmission channel. See
broadband .
channel
The communication pathway between two or more devices.
coaxial cable
A two conductor cable in which an inner conductor is the signal
path and an outer conductor is a shield. A dielectric separates the
two conductors.
Co-Processor
Bridge Multiplexer models BM85S232 and BM85S485. These
models contain a user-defined application program that can
independently control processes at their four serial ports,
accessing Modbus Plus nodes only as required.
CRC
Cyclic Redundancy Checking. An error detection method in which
a sending station computes a mathematical value derived from the
frame’s contents, and sends it as an HDLC field in the frame. The
receiving station recomputes the value as it receives the frame,
and compares it to the received value. If the two values are equal,
the frame is assumed to have been received without error.
data frame
An LLC frame containing data to be transferred between devices.
Data Link Layer
In the OSI model, the layer that provides services for transferring
frames of data between nodes of a network. Defined by the IEEE
802.2 standard. At this layer, a sending device assembles data
into a message packet with addresses and information for error
checking, handles tokens for accessing the network, and sends the