User's Manual

DRAFT 1
TB9300 Installation and Operation Manual Glossary 121
© Tait Limited May 2013
router A router is an internetwork packet switch that switches data packets from
an input interface to an output interface. The interfaces can be of different
types.
RS-232 A protocol for serial communications between a DTE (data terminal
equipment) and a DCE (data communications equipment) device.
RS-485 An updated version of the RS-232 protocol for serial communications
between multiple devices.
RSSI Received Signal Strength Indicator is a level that indicates the strength of
the received signal.
RTP Real Time Protocol is an Internet protocol that supports the real-time
transmission of voice and data.
Rx Receiver.
SAW filter Surface Acoustic Wave filter. A band pass filter that can be used to filter
both RF and IF frequencies. A SAW filter uses the piezoelectric effect to
turn the input signal into vibrations that are turned back into electrical
signals in the desired frequency range.
selectivity The ability of a radio receiver to select the wanted signal and reject
unwanted signals on adjacent channels (expressed as a ratio).
sensitivity The sensitivity of a radio receiver is the minimum input signal strength
required to provide a usable signal.
simplex Able to provide transmission and reception in only one direction at a time.
SINAD Signal plus Noise and Distortion is a measure of signal quality. It is the ratio
of (signal + noise + distortion) to (noise + distortion). A SINAD of 12dB
corresponds to a signal-to-noise ratio of 4:1.
site 1. The base station equipment at a particular location. This includes power
supplies, transmitters, receivers, network interfaces and controllers.
2. The location of that equipment.
SMR Specialized Mobile Radio. A communications system used by police,
ambulances, taxis, trucks and other delivery vehicles.