Patent ID: 7359433

Claim:
A data transmission system for serial asynchronous data transmission between a first unit and a second unit, the data transmission system comprising: a first circuit part associated with the first unit, the first circuit part including: a first transmitter circuit part connected to a first transmitter terminal of the first unit; a first receiver circuit part connected to a first receiver terminal of the first unit; a first terminal for a data transmission line; and a first terminal for a reference potential line; a second circuit part associated with the second unit, the second circuit part including: a second transmitter circuit part connected to a second transmitter terminal of the second unit; a second receiver circuit part connected to a second receiver terminal of the second unit; a second terminal for the data transmission line; and a second terminal for the reference potential line; the second circuit part being interconnectable with the first circuit part via the data transmission line such that the data transmission line directly connects the first transmitter circuit part, first receiver circuit part, second transmitter circuit part, and second receiver circuit part for bidirectional data transmission; and a current source configured for feeding a current into the data transmission line so that: a first signal state of the first receiver terminal is capable of being changed as a function of a second signal state of the second transmitter terminal; and a third signal state of the second receiver terminal is capable of being changed as a function of a fourth signal state of the first transmitter terminal, wherein the current source is a power supply to the first transmitter circuit and first receiver circuit of the first circuit part.