Bidirectional communication

A method for two-way communication between a master system including a master transmitter and at least one slave system including a slave transmitter connected by an active connection wire, the master transmitter and the slave transmitter having a common reference, the master transmitter being able to transmit a master signal to the slave transmitter and the slave transmitter being able to transmit a slave signal to the master transmitter, wherein the method comprises:

• operating the master transmitter , in active state, to cause the master signal to be a digital modulation in voltage, and in standby state, to cause the master signal to be a constant logic state, to detect a current consumption by the slave transmitter and upon detecting such current consumption operable to switch from standby state to active state,
• operating the slave transmitter to signal the master transmitter to switch to active state by consuming current, and to cause the slave signal to be a digital modulation in current, and
• operating each of the master and slave transmitter to use a generic bit frame for communication between the master transmitter and the slave transmitter, said bit frame starting with a start flag comprising six consecutive bits at logic one, and, in the bit frame, a logic zero is inserted on transmission each time there are 5 consecutive bits at logic one.

A master system comprising:

• a transmitter having a common reference connection and an input/output,
• the common reference connection being intended to be connected to a common reference connection of a slave transmitter and the input/output being intended to be connected to an input/output of the slave transmitter, the master transmitter being capable of, in active state, transmitting a master signal to the slave transmitter, the master signal being a digital modulation in voltage, and the master transmitter being capable of receiving a slave signal from the slave transmitter, the slave signal being a digital modulation in current, and in standby state, transmitting a constant logic state to the slave transmitter, and while in standby state is operable to detect a current consumption by the slave transmitter and upon detecting such current consumption operable to switch from standby state to active state,
• and wherein a generic bit frame is used for communication between the master transmitter and the slave transmitter, said bit frame starting with a start flag comprising six consecutive bits at logic one, and, in the frame, a logic zero is inserted on transmission each time there are 5 consecutive bits at logic one.

A slave system comprising:

• a slave transmitter having a common reference connection and an input/output, the common reference connection being intended to be connected to a common reference connection of a master transmitter and the input/output being intended to be connected to an input/output of the master transmitter, the slave transmitter is capable of receiving a master signal from the master transmitter, the master signal being a digital modulation in voltage, the slave transmitter being capable of transmitting a slave signal to the master transmitter, the slave signal being a digital modulation in current, and is capable of signalling the master transmitter to switch to active state by consuming current, and
• wherein a generic bit frame is used for communication between the master transmitter and the slave transmitter, said bit frame starting with a start flag comprising six consecutive bits at logic one, and, in the frame, a logic zero is inserted on transmission each time there are 5 consecutive bits at logic one.