Sierra Wireless DART 200 CDPD Modem - Manual (Page 186)

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.