Rockwell Automation 1747-L40 SLC 500 Fixed Hardware Style - Manual (Page 210)

Glossary
G–1
Glossary
Auto Answer — The type of modem that has self-contained timeouts and
tests. They can answer and hang the phone up automatically.
Backplane Current Draw — The amount of current the module requires
from the backplane. The sum of the backplane current draw for all modules
in a chassis is used to select the appropriate chassis power supply.
Baud Rate — The speed of communication between devices on a network.
All devices must communicate at the same baud rate. For example, the
DH–485 network devices default to 19,200 baud.
Calculated Watts — The amount of heat generated by those points
energized on an I/O module.
Channel — Communication port on a module.
Chassis — A hardware assembly that houses devices such as I/O modules,
adapter modules, processor modules, and power supplies.
Continuous Current Per Module — The maximum current for each
module. The sum of the output current for each point should not exceed this
value.
Continuous Current Per Point — The maximum current each output is
designed to continuously supply to a load.
CPU — Central Processing Unit or processor.
DF1 protocol — A peer–to–peer link–layer protocol that combines features
of ANSI X3.28–1976 specification subcategories D1 (data transparency) and
F1 (two–way simultaneous transmission with embedded responses).
Direct Connect — A type of modem that is connected to a dedicated, leased
phone line and is active at all times.
DH–485 Network — The DH–485 network is a collection of devices
connected to the communication cable allowing information exchange. A
communication network based on the EIA Standard for RS–485 using an
Allen–Bradley proprietary protocol.
DTE Controlled Answer — type of modem that is unattended and is
attached directly to the phone lines. The interface module or the 5/03
processor acts as the Data Terminal Equipment (DTE), which controls the
modem via the DTR, DSR, and DCD signals. The module incorporates
timeouts and tests to properly operate these types of modems.