Slave station with two output circuits commonly and directly connected to a line for serially transmitting data to a master station in two operational modes

A communications system, comprising:

• a master station, at least one slave station, and at least one line connecting said master and slave stations;
• said at least one slave station including a first output circuit and a second output circuit each having an output commonly and directly connected to said at least one line without any active circuitry connected between said outputs of said first and second output circuits;
• said first output circuit of said at least one slave station, in a first operating mode of the system, serially outputting an identification code on said line;
• and
• in a second operating mode, said master station addressing said at least one slave station and said second output circuit of said slave station transmitting data different from the identification code to said master station through said line.