Wavecom W40PC, Manual

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Transmission Modes WAVECOM Decoders v6.15 W40PC, W41PC, W51PC
ZVEI-VDEW 1200 INDIRECT-FM
ZVEI-1 70 ms INDIRECT-FM
ZVEI-2 70 ms INDIRECT-FM
ACARS
Parameter Value
Frequency range VHF
Frequency Europe 131.725, 131.525, 131.825 MHz
Frequency USA 131.550, 130.025, 129.125, 131.475 MHz
Frequency Japan 131.450 MHz
Center frequency 1800 Hz
Shift frequency 1200 Hz
Baudrate 2400 bps
System Packet oriented ARQ (CSMA/CD), Aircraft
communications system
Modulation INDIRECT-AM
Receiver settings AM, narrow
Signal source(s) AF (only)
Alphabet ITA-5 with parity and block coding
A ircraft C ommunications A ddressing and R eporting S ystem (ACARS) is a carrier sensing,
multiple access packet radio system for aircraft communications. ACARS operates in the VHF
band, mainly around 130 MHz, using 2400 bps NRZI coded coherent audio frequency MSK
(Minimum Shift Keying - a particular form of FSK) on AM to make use of standard aircraft
AM communications equipment.
To receive ACARS an omni-directional 108-136 MHz antenna, a VHF AM receiver (scanner)
with 13 kHz channel bandwidth and a corresponding AF output is necessary. As the ACARS
packets are very short turn the squelch of the receiver OFF.
As only one speed (2400 Baud) is used presently, the ACARS menu does not offer the option
of manually selecting a speed.
ACARS Frame
Parameter Value
Pre-key 16 characters All binary „ones„
Bit Sync 2 characters „+„ , „*„
Character Sync 2 characters SYN, SYN (16h)
Start of Heading 1 character SOH (01h)
Mode 1 character
Address 7 characters
Technical Acknowledgement 1 character
Label 2 characters
Block Identifier 1 character
Start of Text 1 character
STX (02h) - if no text ETX (03h)
Text 220 characters maximum, Only printable characters
Suffix 1 character , If single or terminal block ETX, else