Wavecom W61PC V7.5.0 - Manual (Page 251)

WAVECOM Decoder W61PC/LAN Manual V7.5 Transmission Modes  241
Digit Hz Digit Hz
1 970 9 2000
2 1060 A 886
3 1160 B 810
4 1270 C 740
5 1400 D 680
6 1530 E 2400
7 1670
Tone duration: 70 ms
ZVEI-VDEW
The digital selective calling systems ZVEI and VDEW were defined for selective call and data transmission
in the non-public mobile land radio service. The ZVEI system adheres to the recommendation AK SRDS
87-3D, while the VDEW system was known as DIN45013 until 1992. The systems are identical on the
physical layer. Due to the special requirements of the VDEW some additional features where added to the
ZVEI system.
Parameter Value
Frequency range VHF/UHF
Operation modes Digital Selcal
Modulation FFSK
Symbol rate 1200 Bd
Center frequency 1500 Hz
Shift/Bandwidth 600 Hz
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: