Arq-N; Arq-M2-342 And Arq-M2-242 - Wavecom W40PC Manual

ARQ-E3 systems often operate at speeds of 48, 50, 96, 192 and 288 Baud on the radio link.
ARQ-E3 synchronization may be started with the selection of a baud rate. An "AUTO"
program start causes the automatic determination of the frequency shift and baud rate to be
executed first. The signal polarity (USB or LSB sidebands) is automatically detected.
After synchronization to an ARQ-E3 system has been achieved the detected repetition rate is
displayed (4 or 8 cycles). This parameter may give clues to the identity of the transmission.
If the same continuously repeated character (often FFFF) is decoded whilst working in the
ARQ-E3 mode, it is most likely an ARQ-E system which is being monitored. ARQ-E3
employs the ITA-3 alphabet (balanced 3:4 mark-space ratio) for data transmission and error
detection.
For short-wave transmissions synchronous full duplex ARQ (Automated Request) modes have
become very significant.
Full duplex systems transmit a RQ character after having detected an erroneous character or in
the presence of excessive signal distortions. The remote station subsequently repeats the last
three or seven characters preceded by the RQ character.
To maintain synchronization between the two stations both transmitters operate continuously
and send the idle bit pattern if no traffic is transmitted.

ARQ-N

Parameter
Frequency range
System
Baudrate
Modulation
Receiver settings
Signal source(s)
Alphabet
Known ARQ-N systems operate exclusively at a speed of 96 Baud on the radio link.
The synchronization phase for the ARQ-N mode of operation may be initiated via the "Auto"
function or by manual selection of the baudrate.
ARQ-N uses the ARQ-1A alphabet (like ARQ-E). Character inversion (as in the case of ARQ-
E or ARQ-E3) is not defined for ARQ-N. The lack of inversion makes it impossible to
automatically determine the length of the RQ cycle. However, known systems operate
exclusively with a single RQ character and three repeated characters.
Signal polarity (USB or LSB sidebands) is automatically detected.
For short-wave transmissions synchronous full duplex ARQ (Automated Request) modes have
become very significant.
Full duplex systems transmit the RQ character after having detected an erroneous characters or
in the presence of excessive signal distortions. The remote station subsequently repeats the last
three characters preceded by the RQ character.
To maintain synchronization between the two stations both transmitters operate continuously
and send the idle bit pattern if no traffic data is transmitted.

ARQ-M2-342 and ARQ-M2-242

Frequency range
System
WAVECOM Decoders v6.15 W40PC, W41PC, W51PC
Value
HF
DUPLEX, Single channel
96-192 Baud, variable 30-650 Baud
SSB or DIRECT-FSK
CW, LSB or USB
AF, HF or IF
ITA-2 with parity and identification bit
HF
DUPLEX, TDM, REC242/REC342-2
Transmission Modes • 121