Nikon RADIUS CM200 User Manual
Outbound Signalling Word: data transmitted on the control channel from the
central controller to the subscriber unit.
Printed Circuit Board
Private-Line® tone squelch: a continuous sub-audible tone that is transmitted
along with the carrier.
Phase-Locked Loop: a circuit in which an oscillator is kept in phase with a refer-
ence, usually after passing through a frequency divider.
Push-To-Talk: the switch located on the left side of the radio which, when
pressed, causes the radio to transmit.
Random Access Memory: the radio’s RAM is loaded with a copy of the
Short-term data-storage circuits within the microcontroller.
Remote transmit/receive facility that retransmits received signals to improve
Reset line: an input to the microcontroller that restarts execution.
Radio Frequency Power Amplifier
Radio Interface Box
Read Only Memory
Received Signal-Strength Indicator: a dc voltage proportional to the received
RF signal strength.
Software Potentiometer: a computer-adjustable electronic attenuator
Computer programs, procedures, rules, documentation, and data pertaining to
the operation of a system
SPI (clock and data
Serial Peripheral Interface: how the microcontroller communicates to modules
and ICs through the CLOCK and DATA lines.
Muting of audio circuits when received signal levels fall below a pre-determined
An operating mode whereby the radio is muted but still continues to receive
System Central Con-
Main control unit of the trunked dispatch system; handles ISW and OSW mes-
sages to and from subscriber units (see ISW and OSW).
The act of selecting the desired operating system with the system-select switch
(also, the name given to this switch).
Time-Out Timer: a timer that limits the length of a transmission.