Start-of-message generator for facsimile transceiver - describes mode of operation using clock pulses between two synchronisation words

摘要

The start-of-message generator selects one special mode from amongst several modes of operation each having a given code. The selected mode is coded. A start-of-message sync. word is generated and immediately afterwards a clock is triggered to produce a selected number of clock pulses depending on the coded selected mode of operation. At the end of the clock-pulse train a second sync. word is generated. A start-of-message decoder receives the first and second start-of-message sync. words. The clock pulses are counted by a counter which is enabled in the time interval between the sync. words. The number of counted clock pulses is translated back into the selected mode of operation.