Глоссарий терминов APCO25
к английской версии
Glossary of Terms of APCO25
к русской версии
ACP – Adjacent Channel Power
APCO International—Association of Public-Safety Communications Officials - International, Inc.
ARQ – Automatic Retry Request (to retry corrupted packets)
BER-Bit Error Rate
BR—Base Radio (A reference designating a base station)
C4FM—Compatible four-level frequency modulation
CAI- Common Air Interface
CQPSK – Compatible quadrature phase shift keying
CRC—Cyclic Redundancy Checksum (For data error detection)
DES – Data Encryption Standard
DiBit—Two bits grouped together to represent a four-level symbol
DPSK – Differential Phase-Shift Keying
ES—Encryption Synchronization (Information embedded in voice)
FDMA – Frequency Division Multiple Access
FS—Frame Synchronization (Marks the first information bit)
FSK—Frequency Shift Keying
Golay—A standard error correction code
Hex Bit—Six bits grouped together to represent a Reed-Solomon code symbol
IMBE vocoder -- Improved Multiband Excitation vocoder, providing 4400 bits/s of digitized voice
IQ – In-phase / quadrature
KID—Key Identifier (Indicates the encryption key for the message)
LC—Link Control (Information embedded in voice)
LLC—Logical Link Control (Sub-layer of the OSI Data Link Layer)
LSD—Low Speed Data (Data embedded in voice)
MAC—Media Access Control (Sub-layer of the OSI Data Link Layer)
MI—Message Indicator (To initialize encryption)
MSK – Minimum-shift keying
NASTD— International and the National Association of State Telecommunications Directors
Project 25 Phase I – The backwards compatible migration path to full
Project 25 specification that specifies a 12.5 kHz bandwidth using C4FM
modulation
Project 25 Phase II – The backwards compatible migration path to full
Project 25 specification that specifies a 6.25 kHz bandwidth using
CQPSK modulation
NID—Network Identifier (The code word following the frame link)
Octal—Base 8 notation for numbers (also called radix 8)
Octet—Eight bits grouped together (Also called byte)
OSI—Open Systems Interconnection reference model
QPSK—Quadrature Phase Shift Keying modulation for data
QPSK-c—Compatible Quadrature Phase Shift Keying (Family of modulations)
RS—Reed-Solomon error connection code
SAP—Service Access Point (Where a network provides service)
STS – System to system, one of the proposed approaches to interoperability testing
TDMA – Time Division Multiple Access
TETRA – Terrestrial Trunked Radio: An open digital trunked radio
standard defined by the European Telecommunications Standards Institute
TIA – Telecommunications Industry Association
Type III Encryption—Type of encryption used for non-classified communications
Type IV Encryption—Type of encryption used for export
UM—Common Air Interface reference point |