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Transmission Modes WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V9.1.0
bottom of the first column (left) to the top of the last column (right) covering a matrix of 7 columns x 14
lines. Pixels are always sent in pairs.
Graphic Mode, Broadcast/simplex
By selecting the mode with a baud rate of 122.5 Bd, reception is started. Selecting Polarity will determine
normal or inverse screen color.
FMS-BOS
FMS-BOS is a radio signaling system for security authorities and organizations. The system allows for a
major reduction in message interchange between mobile units and a control center by digital transmission
of abbreviated telegrams.
BCD-Code with block coding
FMS-BOS operates at 1200 bit/s using FSK modulation of 1200 Hz and 1800 Hz tones.
FMS-BOS Transmission Example
The FMS-BOS data telegrams always have the same structure and a length of 48 bits regardless of the
transmission direction or message contents. The actual information is contained in 40 bits. The BCD code
is used to transmit the digits in the telegram.
A FMS-BOS message is preceded by 12 bits of carrier and a sync character (0x1a).
The message itself consists of 10 BCD blocks.
Block 1 is the BOS service identifier (0...f) identifying the service issuing the message.
Block 2 is the state identifier (0...f) identifying the German state. Due to the fact that the number of
states exceeds the number of available identifier digits, digits E and F are additionally identified by the lo-
cation identifier to be used by two states each.
Blocks 3 - 4 are the location identifier (e.g., OK 10) and can assume one of 99 different possibilities.
The actual value is determined by each individual state.
Blocks 5 – 8 are the vehicle identifier (e.g., 4213) and can contain one of 9999 combinations. The indi-
vidual identifiers are assigned by each specific service.
Block 9 is the status field contains the actual information. 16 different messages may be transmitted. De-
pending on the R direction bit status messages attain different meanings. Furthermore the actual meaning
of a status message is determined by the service and the individual states.