Receipt acknowledgement method in multiplex transmission

A receipt acknowledgement method in multiplex transmission in which data transmission is conducted data frame by data frame among a plurality of nodes connected to one another through a common multiple transmission line, each data frame including a data frame area followed by an acknowledgement signal as measured along a time axis, said method being of the type including a step of returning an acknowledgement signal at a predetermined timing from each of receiving ones of normal ones of said nodes which have normally received one said data frame, after entry into the acknowledgement signal area of each data frame, said method comprising the steps of:

• periodically sending out first signals from a transmitting one of said nodes, each said first signal including at least one dominant bit at a predetermined bit interval,
• periodically sending out second signals, each including at least one recessive bit at the predetermined bit interval, from the transmitting node,
• returning an acknowledgement signal from each of the normal receiving nodes in the form of an NRZ code in synchronization with one corresponding said dominant bit included in a corresponding one of the first signals periodically sent out from the transmitting node,
• setting the predetermined bit interval so that a bit stuff rule is established with respect to the acknowledgement signal area irrespective of the number of the normal receiving nodes so that when there are a predetermined number "n" of consecutive bits of the same sign where, at least one bit whose sign is opposite to that of the "n" bits is inserted immediately after the "n" bits, and
• dividing each of the acknowledgement signal areas into a plurality of small areas, each small area starting with a respective said first signal and ending with a respective said second signal, each small area being assigned to less than (n-1) of said plurality of nodes, and including less than (n+1) bits.