Patent ID: 6728309
Filing Date: 2004-04-27
Classification: H04L

Abstract:
A communication system for transmitting data over a four-wire subscriber line, the system including:a first data terminal device, the first data terminal device having a data output control terminal, a data output terminal, a data input control terminal and a data input terminal; and a first modem having a receive section and a transmit section, where: the receive section of the first modem has first and second line input terminals for coupling to a first pair of wires of the four-wire subscriber line, a receive control output terminal coupled to the data input control terminal of the first data terminal device for outputting a signal to the first data terminal device when a first encoded data signal is present on the first pair of wires, and a receive data output terminal coupled to the data input terminal of the first data terminal device, where the receive section of the first modem is configured to decode the first encoded data signal present on the first pair of wires according to a predetermined data transmission protocol in order to generate a first unencoded data signal at the receive data output terminal, and the transmit section of the first modem has first and second line output terminals for coupling to a second pair of wires of the four-wire subscriber line, a transmit control input terminal coupled to the data output control terminal of the first data terminal device for receiving a signal from the first data terminal device that the first data terminal device is going to output a second unencoded data signal on the data output terminal of the first data terminal device, and a transmit data output terminal coupled to the data output terminal of the first data terminal device, where the transmit section is configured to encode the second unencoded data signal received on the transmit data output terminal according to the predetermined data transmission protocol in order to transmit a second encoded data signal on the second pair of wires.