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Transmission Modes WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V9.1.0
DUP-FEC-2 has a radio channel rate of 125 or 250 Baud. A data frame is 32 bits long. For error protection
a five bit CRC-sum (inverted Hamming) and a single bit for global parity (odd parity) is used.
DUP-FEC-2 is often used as a full-duplex system. As is the case with other full-duplex systems transmis-
sion simultaneously takes place on two different frequencies. If an error occurs special sequences are
transmitted to signal this condition and a block repetition is requested (RQ).
If errors are received the two last 32 bit blocks are retransmitted when the radio channel rate is 125 Baud
and three blocks when working at 250 Baud.
Like DUP-ARQ-2, DUP-FEC-2 has many special blocks for IDLE and RQ.
DZVEI
The entire call number is transmitted by consecutive tones in decade sequence. When two identical digits
are to be transmitted consecutively, then an eleventh frequency is used as a repetition identifier.
If more than two identical digits are to be transmitted, the repetition tone is appended to the digit tone
(e.g., 22222 is transmitted as f2 fw f2 fw f2, where f2 is the tone for "2" and fw is the repetition tone).
In most systems the accuracy of the single frequencies has to be within +1/-1.5% of the nominal value.
For ZVEI modes having nominal tone durations of 70 ms, the duration of a single tone may vary ± 15 ms.
Decoding the selective calls is started by clicking on a system. If transmission and system selection con-
form, the call sign is displayed on the monitor. In the Options menu a Time stamp function can be enabled
to add date and time to each call.
Tone Allocation
Tone duration: 70 ms.
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