Resistance coupled data transmission arrangement

A data transmission arrangement comprising a two-wire direct-coupled transmission path operated in the differential mode and terminated by terminations having its characteristic impedance;

• a data signal transmitter comprising output means for connecting to said transmission path;
• and a receiver comprising input means for connecting to said transmission path, a supply voltage source and a comparator,
• characterized in that said path has two ends;
• portions of said transmission path, output means for connecting, and input means for connecting together form a pure resistance coupling network providing conductive coupling between said transmitter and receiver,
• said network comprises two transmitter resistors, in said output means for connecting;
• at least two termination resistors, in the data transmission path terminations;
• and a plurality of receiver divider resistors and two matching resistors, in said input means for connecting,
• each transmitter resistor being connected to a respective wire of said transmission path, for coupling to said path a signal to be transmitted,
• each matching resistor being connected between a respective wire of said transmission path and a corresponding input of said comparator for producing opposite voltage level differences at the comparator input in response to transmission of a given signal,
• each termination comprising a respective one said termination resistor, each termination resistor having a value equal to said characteristic impedance,
• during data transmission, a voltage difference between the transmission wires having opposite levels, and
• each said receiver divider resistor being respectively connected between said supply voltage source and one or the other of said corresponding inputs of said comparator for producing an absolute voltage level at the corresponding comparator input in response to loss of signal from one wire in the transmission path.

A data transmission arrangement comprising a two-wire direct-coupled transmission path operated in the differential mode and terminated by terminations having its characteristic impedance;

• a data signal transmitter comprising output means for connecting to said transmission path;
• and a receiver comprising input means for connecting to said transmission path, a supply voltage source and a comparator,
• characterized in that the transmitter comprises two transistors for coupling data signals into the output means for connecting;
• and said output means comprises at least one diode connected between each said transistor and a corresponding wire of the transmission path to form a series circuit,
• portions of said transmission path, output means for connecting, and input means for connecting together form a pure resistance coupling network providing conductive coupling between said transmitter and receiver, and
• said network comprises two transmitter resistors, in said output means for connecting;
• at least two termination resistors, in the data transmission path terminations;
• and a plurality of receiver divider resistors and two matching resistors, in said input means for connecting,
• each transmitter resistor being part of a respective said series circuit, for coupling to said path a signal to be transmitted,
• each matching resistor being connected between a respective wire of said transmission path and a corresponding input of said comparator for producing opposite voltage level differences at the comparator input in response to transmission of a given signal, and
• each said receiver divider resistor being respectively connected between said supply voltage source and one or the other of said corresponding inputs of said comparator for producing an absolute voltage level at the corresponding comparator input in response to loss of signal from one wire in the transmission path.