Section 4 Definitions; Meter Or Dce; Computer Or Dte; Point To Point - Omega DP41-B Series User Manual

4. Definitions
This Guide uses some abbreviations and compact wording to signify devices and
concepts with detailed descriptions. Significant items are:

4.1 METER OR DCE

The term "METER" signifies one or more meters (or devices with compatible
communications) which respond to the commands (requests) of a controller device
such as a computer. Such meters are classified as "DCE" devices, from the older
"Data Communication Equipment" telephone specifications.

4.2 COMPUTER OR DTE

These descriptors signify the device controlling the communications, such as a
computer ("HOST" device) or programmable controller. Telephony specifications refer
to controllers as "Data Terminal Equipment" or DTEs.
4.3 POINT-TO-POINT
Direct connection between two (and only two) devices for data exchange, such as the
meter and your digital computer. No addresses are used unless the meter is
programmed for a "one-meter bus".

4.4 MULTIPOINT (MULTI-DROP)

Shared wiring for a DTE and more than one DCE, designates a "BUS". Several panel
meters and a personal computer can share a bus, with the computer serving as
controller. The controller can acquire data by transmitting the preassigned address for
a meter followed by a command for the meter to send selected information. When
used with the meter, up to 31 meters can share a bus (with addresses from 01 to
decimal 199); all meters receive the data when the address is "00".

4.5 SIMPLEX

A channel (path, typically a twisted pair of wires) with unidirectional data flow.

4.6 HALF DUPLEX

A channel (e.g., twisted pair) with bi-directional data flow, but only in one direction at a
time.

4.7 FULL DUPLEX

Two channels (e.g., two twisted pairs) with bi-directional data flow at any time (one
simplex channel in each direction).
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