Data communication apparatus especially for facsimile transmission

摘要

The apparatus includes a switching selector which switches the transmission mode between a high transmission mode and a low transmission mode dependent on a received switch signal. A modus detector detects if the selector has switched the transmission mode to the low transmission mode. A timer start measuring the time after the selector has switched the transmission mode from the high transmission mode to the low transmission mode. A rate detector detects the data bit rate in the high transmission mode. A calculator calculates a waiting time based on the detected bit rate. An interruption unit is provided which interrupts a telephone line, if the measured time exceeds the waiting time.