Abstract: An open circuit detection apparatus is provided for detecting whether a connection is closed between a local node and a remote node having a known impedance. A ping source is connected to the local node. The ping source has an output for transmitting an address unique to the remote node and an input for sensing the impedance of the remote node. A test circuit is connected to the remote node. The test circuit has an address decoder for receiving the address from the output. The address decoder has a unique address and asserts a control signal upon the address matching the unique address of said address decoder. An impedance-varying device is responsive to the control signal and effects a change in the impedance of the remote node. The change in the impedance of the remote node is sensed by the input of the ping source.

Abstract: An open circuit detection apparatus is provided for detecting whether a connection is closed between a local node and a remote node having a known impedance. A ping source is connected to the local node. The ping source has an output for transmitting an address unique to the remote node and an input for sensing the impedance of the remote node. A test circuit is connected to the remote node. The test circuit has an address decoder for receiving the address from the output. The address decoder has a unique address and asserts a control signal upon the address matching the unique address of said address decoder. An impedance-varying device is responsive to the control signal and effects a change in the impedance of the remote node. The change in the impedance of the remote node is sensed by the input of the ping source.

Abstract: An open circuit detection apparatus is provided for detecting whether a connection is closed between a local node and a remote node having a known impedance. A ping source is connected to the local node. The ping source has an output for transmitting an address unique to the remote node and an input for sensing the impedance of the remote node. A test circuit is connected to the remote node. The test circuit has an address decoder for receiving the address from the output. The address decoder has a unique address and asserts a control signal upon the address matching the unique address of said address decoder. An impedance-varying device is responsive to the control signal and effects a change in the impedance of the remote node. The change in the impedance of the remote node is sensed by the input of the ping source.

Abstract: A data exchange gateway for enabling the exchange of data between a vehicle data bus (VDB) and an intelligent transportation system (ITS) data bus. The gateway includes a memory accessible by both a VDB interface and an ITS data bus interface so that data and commands may be shared between each respective bus through the shared memory.

Abstract: A vehicle communications network is provided which includes a ground translation circuit and interfacing transmitter circuits that achieve smooth current sourcing transitions. Included is a communications bus such as a J1850 having multiple-access for interfacing with a plurality of electronics, preferably within a vehicle. Each transceiver has a transmitter and receiver interfaced with the bus. The transceiver is coupled via a resistive element to the communications bus and sources current onto the bus when the transmitter output voltage exceeds the bus voltage. The added resistance advantageously reduces changes in current which may otherwise exist on the communications bus when current sourcing switches on and off.

Abstract: A circuit monitors both digital and analog sensor readings by polling them from a single wire bus multiplex system. The circuit operates to sequentially address a plurality of smart sensor interfaces, each having an associated sensor, connected to the single wire bus. A voltage signal is supplied on the line that produces a current corresponding to the presence of a sensor at the polled interface and a current corresponding to a sensed digital or analog value where the sensor is of the digital or analog type, respectively. The currents on the bus are copied in a current mirror whose current output is applied to a resistor to produce a voltage, which in turn is converted into a digital number to be analyzed to determine the presence of a sensor at the addressed interface and its status. The current in the circuit is also measured to produce a voltage corresponding to circuit component variations and one corresponding to the contributions of the currents from the power supplies of the interfaces.

Abstract: A vehicle communications network is provided which includes a ground translation circuit and interfacing transmitter circuits that achieve smooth current sourcing transitions. Included is a communications bus such as a J1850 having multiple-access for interfacing with a plurality of electronics, preferably within a vehicle. Each transceiver has a transmitter and receiver interfaced with the bus. The transceiver is coupled via a resistive element to the communications bus and sources current onto the bus when the transmitter output voltage exceeds the bus voltage. The added resistance advantageously reduces changes in current which may otherwise exist on the communications bus when current sourcing switches on and off.

Abstract: A ground translation circuit in a transmitter of a transceiver of a data transmission network for transferring symbol information contained in analog pulses from circuits referenced to logic signal power to circuits referenced to an independent DC voltage ground return for transmission over a bus. Complementary ground translation circuits in a receiver of the transceiver for transferring the analog pulses referenced with respect to the independent DC ground return back to circuits referenced to logic signal power.

Abstract: A transceiver device for use with a microcontroller and a symbol encoder decoder device (forming a node in a communications network) for transmitting and receiving variable pulse width modulated (VPWM) analog signals containing symbol messages over a communications bus. The transceiver accepts digital VPWM signals from the symbol encoder decoder device which were generated by the microcontroller and converts the digital signals into VPWM analog signals and then transmits the analog signal over the bus to other nodes. The transceiver also receives VPWM analog signals placed on the bus by other nodes of the network and transfers the signals in digital form to the symbol encoder decoder device which, in turn, communicates the decoded messages to the microcontroller.

Abstract: A symbol encoder and decoder device for use with a microcontroller and a transceiver (forming a node) for encoding and decoding defined symbols made up of digital bits of various lengths and for transferring to and recovering symbol messages on a single wire bus of a multi-node multiplexed data link.