WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V9.1.0 Transmission Modes
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Variable Information Field With Supplementary Information
The ETS 300 133-4 standard has a very fine grained subdivision of the VIF and this enables ERMES to be
used for a wide range of applications.
ERMES and other pager systems are losing importance in Europe due to the surge in GSM usage, and sev-
eral networks have been closed down.
EURO
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.
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 ena-
bled to add date and time to each call.
Tone Allocation
Tone duration: 100 ms.
FEC-A
FEC-A uses a convolutional error correction scheme based on data bits being read into a shift register, the
length of which may be changed. Values of 72 and 128 bits are common.
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