Motorola Portable Radio Ep450 Basic Hkln4215a Manual

							December 3, 2003HKLN4215A
G-2 
PLLPhase-Locked Loop: a circuit in which an oscillator is kept in phase with a refer-
ence, usually after passing through a frequency divider.
PTT Push-To-Talk: the switch located on the left side of the radio; when pressed, 
causes the radio to transmit.
RAMRandom Access Memory: the radio’s RAM is loaded with a copy of the EEPROM 
data.
Registers Short-term data-storage circuits within the microcontroller.
RESETReset line: an input to the microcontroller that restarts execution.
RF PA Radio Frequency Power Amplifier
RIBRadio Interface Box
ROM Read Only Memory
RSSIReceived Signal-Strength Indicator: a dc voltage proportional to the received RF 
signal strength.
RPT/TA Repeater/Talk Around
SoftpotA computer-adjustable electronic attenuator
Software Computer programs, procedures, rules, documentation, and data pertaining to 
the operation of a system.
SPI (clock and data 
lines)Serial Peripheral Interface: how the microcontroller communicates to modules 
and ICs through the CLOCK and DATA lines.
Squelch Muting of audio circuits when received signal levels fall below a pre-determined 
value.
Standby ModeAn operating mode whereby the radio is muted but still continues to receive data
TOT Time-Out Timer: a timer that limits the length of a transmission.
TPLTone Private-line
µC Microcontroller
UHFUltra High Frequency
µP Microprocessor
VCOVoltage-Controlled Oscillator: an oscillator whereby the frequency of oscillation 
can be varied by changing a control voltage.
VCOBIC Voltage-Controlled Oscillator Buffer Integrated Circuit
VHFVery High Frequency
VSWR Voltage Standing Wave RatioTerm Definition