for a communication system for the transmission of digital information over a bus channel using pulses having a considerably different pulse length for the transmission of &# 34 ; 0 &# 34 ; and &# 34 ; 1 &# 34 ; bits , respectively . in the preferred embodiment the length of a &# 34 ; 0 &# 34 ; pulse is at least 2 . 1 times longer than the length of a &# 34 ; 1 &# 34 ; to pulse , so that the tolerance on detection of the reception has ample room to absorb wide tolerances in the frequency of a rc - clock generator , e . g . ± 25 %, for propagation time delays and for any inaccuracy in the moment of detection when pulse edges of low steepness must be used .