Sierra Wireless DART 200, User Manual

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DART 200 CDPD Modem User’s Guide Glossary
Sierra Wireless, Inc. Glossary-6
PPP
Point-to-point protocol
An alternative communications protocol used between
computers, or between computers and routers on the
Internet. An enhanced SLIP.
See also, SLIP.
RC4
The encryption algorithm used by CDPD for data
transmissions between the M-ES and the MDIS.
RF
Radio Frequency
RI
Ring Indicator
One of the RS-232 signal lines. Not currently used by the
DART.
RRM
Radio Resource Management
The process of managing CDPD channel acquisition,
channel hopping, cell transfer, and transmitted signal
strength.
RS-232 An EIA hardware standard; it defines the most common
type of serial communications port hardware. It covers
signal definitions, pin assignments, voltage and
impedance levels, and inter device-signaling rules.
RSSI
Receive Signal Strength Indication
The signal power level at the antenna of the modem,
usually measured in dBm.
See also, dBm.
RTS
Request To Send
One of the RS-232 signal lines. Used in hardware flow
control.
RTU
Remote Terminal Unit
Another name for a MAS; usually implies a fixed location
telemetry device
RXD
Received Data
One of the RS-232 data lines.
SABME
Set Asynchronous Balanced Mode Extended
Sent by the M-ES as the first step in CDPD link
establishment.
S-Registers
Status Registers
A set of storage locations within the modem that hold
status and control information for use by the modem
firmware and the users application. Many can be set by
the user when configuring the modem, or when activating
diagnostic functions.
SER
Symbol Error Rate
Percentage of symbols in error. See also, SIE.