Wavecom W74PC V8.7.0 - Manual (Page 274)

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Transmission Modes WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V8.7.0
Parameter Value
Receiver settings FM, BW = 12 kHz
Input format(s) AF, IF
Additional Info BCD-Code, ZVEI and VDEW digital selective calls differ in codeword inter-
pretation and BAK
In the VDEW system it is possible to concatenate up to four telegrams. The basic telegram (Grundtele-
gramm) is followed by one or more follow-up telegrams (Folgetelegramme).
The difference between both systems is the BAK (Betriebsartenkennung). VDEW uses the BAK to indicate
follow-up telegrams, ZVEI does not. The BAK for the whole message is transferred in the last follow-up
telegram. By means of the BAK the decoder detects if it is a VDEW message with follow-up telegrams.
The transmission speed is 1200 bps and the FFSK nominal frequencies are 1200 Hz for logical '1' and 1800
Hz for logical '0'. Indirect modulation (sub carrier) is used. A data packet consists of 64 bits. After a carrier
pre-keying, an 8 bit telegram preamble and a 15 bit Barker sequence follow. Data is protected by using 8
bit redundancy.
Mode labeling for ZVEI and VDEW (BAK:)
There are 16 different values for the various call types:
Parameter hex Value ZVEI (first data word) Value VDEW (following data words)
0 User defined Not used
1 Call to mobile Call to mobile
2 Call to base station Direct Access
3 Identification Identification
4 Acknowledgement Acknowledgement
5 Spare (indicate VDEW) Sequence telegram
6 Separation call Separation call
7 Spare Recall
8 Priority call Emergency call
9 Status request Status request/response
A Spare Position request
B Acknowledgement Acknowledgement
C Spare Quick dialing
D User defined Data
E User defined Spare
F Emergency call Not used
Status for ZVEI and VDEW (STAT:)
Four bits are available. In the VDEW system these four bits indicate the number of follow-up telegrams.
The last follow-up telegram and a basic telegram without follow-up telegrams are indicated by 0xA. In
ZVEI the status bits can be used by the carrier.
Rhombic labeling (RAUTE:)
Four bits are used as additional distinction for a producer designation. The use is not determined.
Manufacturer identification (Herst:)
Two digits are used. The classification is determined by ZVEI.