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08/06/07
68P81096E90-F
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S
SCM
Station Control Module; station controller.
SINAD
Acronym for the ratio of signal plus noise plus distortion and noise plus distor-
tion.
SMR
Schaumburg Manual Revision
Smart Repeater
Trunking system in which channel control is distributed among several repeat-
ers.
Spectra-TAC
Analog Total Area Coverage voting comparator used to select wide area receiv-
ers.
SPI
Serial Peripheral Interface (clock and data lines); simple synchronous serial in-
terface for data transfer between processors and peripheral ICs.
Squelch
Automatic receiver quieting accomplished by muting audio circuits when re-
ceived signal levels fall below a pre-determined value.
SRAM
Static RAM, memory chip used for scratchpad memory.
T
TCC
Trunking Central Controller; main control unit of the trunked dispatch system;
handles ISW and OSW messages to and from radios in the field (See ISW and
OSW).
TOC
Turn Off Code; alternating binary pattern used by DPL signalling to provide fast
muting of the receiving radio.
TRC
Tone Remote Control
Trunking
Radio control system which permits efficient frequency utilization and en-
hanced control features.
Type II Trunking
Motorola trunking system which provides extended features.