136 Glossary TB7100 Installation and Operation Manual
© Tait Electronics Limited December 2005
repeater
A repeater receives a radio signal and re-transmits it. Use of a repeater 
increases the coverage area of a two-way radio system and ensures more 
reliable performance in areas where signals are reflected or attenuated by 
buildings or terrain.
In a repeater-based system, the radio’s transmit frequency is the frequency 
the repeater is listening on, and the radio’s receive frequency is the frequency 
the repeater re-broadcasts signals on.
receive (Rx) 
frequency
The receive frequency is the frequency that a radio is currently tuned to.
reverse tone burst Reverse tone bursts (RTB) can be used with CTCSS. When reverse tone 
bursts are enabled, the phase of the generated tones is reversed for a number 
of cycles just before transmission ceases. If the receiver is configured for 
reverse tone burst, it responds by closing its gate faster than if the RTB were 
not transmitted.
RF RF stands for radio frequency and refers to the part of the electromagnetic 
spectrum used to transmit radio and television signals.
RSSI RSSI (Received Signal Strength Indicator) feature that indicates the strength 
of the received signal. 
Rx Rx is an abbreviation for receive or receiver.
S
sensitivity The sensitivity of a radio receiver is the minimum input signal strength 
required to provide a useable output.
SINAD 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 voltage ratio of 4:1.
subaudible 
signalling
Subaudible signalling is signalling that is at the bottom end of the range of 
audible frequencies. The base station supports CTCSS and DCS subaudible 
signalling. 
subtone A subtone (subaudible signalling tone) is a CTCSS tone or a DCS code. 
switching range The switching range is the range of frequencies that the equipment is tuned 
to operate on.
system interface The system interface is the set of inputs to and outputs from the base station 
(excluding RF), provided by a module inside the tray.