Abstract: A semiconductor integrated circuit device is provided with a diagnosis circuit, which does not increase the delay of a logic element in normal operation. In a latch provided at the output of a memory or at the input of a logic stage, a signal selector is provided in the feedback loop of the latch. The selector is switched in correspondence with the operation mode, such that it transfers the feedback signal in normal operation, while it transfers the test signal in a test mode, in order to prevent the delay from increasing in the signal selector on the main path in normal operation.

Abstract: An address signal is transferred from an address bus transmitting an address from an address generation circuit, to a real address bus connecting to a decoder for decoding an applied address signal, via a branch node, a branch address bus and contacts. The real address bus and the branch address bus are electrically connected at a plurality of points using the contacts. The branch address bus functions as a lining or backing signal line to the real address bus, and a line resistance and line capacitance of the real address bus can be equivalently reduced. A variation in signal propagation delay over an entire decoding circuits is suppressed.

Abstract: An apparatus for protecting an integrated circuit formed in a substrate and a method for protecting the integrated circuit against reverse engineering includes an active shield having a signal transmitter, a signal receiver, at least two conductor tracks running between the signal transmitter and the signal receiver, and a drive and evaluation device connected to the signal transmitter and to the signal receiver. The shield at least partially covers the integrated circuit. A covering composition applied on the substrate forms a mechanical protection of the integrated circuit. The shield has a switching apparatus. As a result, a capacitive measurement method can be carried out in a first switching state and damage to the shield can be detected in a second switching state.

Abstract: Multiple level logic bus drivers and receivers communicate over a bus using a multiple-level logic protocol that transfers multiple bits on each signal wire of a bus in a given interval without increasing the bus width or power dissipation. In one embodiment, four logic levels are employed using CMOS transistor circuitry operating with low voltage (e.g., 1.2V or 1.3V) power supplies (Vdd) and P and N transistor threshold voltage levels of Vtp and Vtn on the order of 0.4--0.5V. Thus, the separation between the following four logic levels is approximately uniform: Vdd; Vdd−Vtp; Vss+Vtn; and Vss. The approximately equal voltage gaps between each quantization level provide uniform noise margins for all levels. A bus noise minimization scheme and a quick recovery scheme ensure the correct data transfer in the presence of injected noise. An initial over drive feature is disclosed for shorter transition times.

Abstract: A pad circuit and operating method for automatically adjusting gains is disclosed, wherein the pad circuit is embedded in an integrated circuit chip that further includes a core logic circuit therein. The pad circuit includes an input/output pin, a gain-adjustable output buffer, an input buffer and a signal feature detector. The method includes the steps as follows. A test signal is firstly issued from the core logic circuit to the gain-adjustable output buffer, while the test signal is then manipulated and outputted to an external device via the input/output pin. Next, a feedback test signal is fed into the input buffer from the external device, while a test result is realized according to a waveform feature of the feedback test signal. Finally, the gain of the gain-adjustable output buffer is adjusted according to the obtained test result.

Abstract: A low-pass filter 10 on a microprocessor bus 22 for attenuating radio frequencies from digital signals travelling on the bus 22 from a microprocessor 12 to a peripheral device 20. An RC network is implemented as close as physically possible to the junction of the bus connection to microprocessor 12 and memory 14 to filter radio frequencies to an extent that limits radiation of these frequencies from the length of the bus 22. Wait states are adjusted as necessary to accommodate filtering of the digital signal that is transmitted over microprocessor bus 22.

Abstract: An apparatus comprising a first circuit, a second circuit and a third circuit is disclosed. The first circuit may be configured to generate a plurality of intermediate signals from a data signal. Each of the intermediate signals may be switchable between (i) a common delay and (ii) one of a plurality of different staggered delays determined by a stagger signal. The a second circuit may be configured to generate a plurality of first drive signals by gating the intermediate signals with a plurality of enable signals. The a third circuit may be configured to generate a plurality of first output signals at a transmit interface of a chip by buffering the first drive signals.

Abstract: A termination network simultaneously provides a voltage-limited output direct current (dc) bias and termination of a broadband distributed amplifier operating down to an arbitrary low frequency. It is capable of being fabricated in a single Integrated Circuit (IC) chip, without the excess power dissipation associated with biasing through a termination resistor, and without the use of external inductor networks. It also limits the maximum dynamic voltage swing on the outputs of the active gain devices used within the distributed amplifier, so as to increase the reliability of the distributed amplifier under large signal over drive conditions.

Abstract: According to some embodiments, provided are a first signal line, the first signal line coupled to a first repeater, the first repeater to convert a first signal from a received signal level to an output signal level, the first repeater to convert from a first signal level to a second signal level slower than from the second signal level to the first signal level, and a second signal line adjacent to the first signal line, the second signal line coupled to a second repeater adjacent to the first repeater, the second repeater to convert a second signal from a second received signal level to a second output signal level, the second repeater to convert from the first signal level to the second signal level slower than from the second signal level to the first signal level, wherein the received signal level is substantially equivalent to the second output signal level and wherein the second received signal level is substantially equivalent to the output signal level.

Abstract: The invention relates to an arrangement (10) and a method for adjusting the slope times of one or more drivers (90) in such a way that the adjustment is essentially independent of external conditions. The invention also relates to a driver circuit. The arrangement (10) is provided with a device (20) for detecting the time history of an output voltage that is output and supplied to a load (12) by means of the driver/s (90). The measured time values are converted into an output voltage value in a device (36) for converting the measured time history of the output voltage. Moreover, a device (40) for generating a reference voltage value is provided. The device (40) is connected to a device (60) for predetermining a desired slope time for the driver/s (90), whereby the slope time is essentially independent of external conditions.

Abstract: An improved data driver, method, and system for driving data with an improved slew rate and eye opening is provided. In one embodiment, the data driver includes a non-precompensating data driver and a precompensating data driver. The non-precompensating driver generates a non-precompensating output data pulse corresponding to input data. The non-precompensating data driver generates a pulse in response to every input data bit received. The precompensating driver generates the precompensating pulse only in response to a transition from one data state to a second data state between consecutive data bits. The precompensating data pulse is shorter in duration than the non-precompensating output data. The output data from the data drive is the sum of the non-precompensating output data pulse and the precompensating output data pulse.

Abstract: A level translating digital switch in which a switching element provides switching and level translation between a first system and a second system that operate using different logic supply voltages. In a situation where the supply voltage for the first system is larger than the supply voltage for the second system, the switching element is driven by a voltage lower than the logic supply voltage of the first system.

Abstract: An apparatus comprising (i) an input circuit configured to provide a predetermined voltage tolerance in response to a plurality of control signals and (ii) a control circuit configured to generate the plurality of control signals in response to one or more input signals.

Abstract: A circuit board configured to provide multiple interfaces is disclosed. The circuit board comprises a termination slot inserted with a termination module configured to modulate circuits by applying a termination resistance and a termination voltage. If the termination module is inserted into the termination slot, the circuit board operates as a series stub terminated transceiver logic (SSTL) interface. Otherwise, the board operates as a low voltage transistor logic (LVTTL) interface. Additionally, the board comprises a switch configured to selectively connect a termination resistance to a bus. If the switch connects the termination resistance to the bus, the board operates as an SSTL interface. Otherwise, the board operates as an LVTTL interface.

Abstract: In apparatuses (1, 2, 3) controlled or operated via an I2C bus, it may be necessary to take measures to suppress interference signals at the data signal input/output of the respective apparatus without impairing the data transport at the same time. The data line (SDA) at the data signal input/output contains an RC element (RS, C), in the form of a low-pass filter, with a diode (D) connected in parallel with the RC element (RS, C), the low-pass filter action allowing said arrangement to be used to suppress interference signals acting on the data signal input/output, and, secondly, the transmissive action of the diode (D) meaning that said arrangement does not impair a data signal (ACK) leaving the data signal input/output.

Abstract: A peripheral device includes a data port having high and low impedance terminations, a transmitter having a data signal generator and a receiver detector. The data signal generator is electrically coupled to the low impedance termination of the data port when in a low impedance operating mode, and to the high impedance termination when in a high impedance operating mode. The receiver detector includes a noise detector adapted to detect a presence or an absence of rail-to-rail noise at the data port when the transmitter is in the high impedance operating mode.

Abstract: In some embodiments, the invention involves multiple integrated circuit stubs coupled in series. At least one of the integrated circuit stubs including first conductors to receive signals from a first adjacent one of the integrated circuit stubs, second conductors to provide signals to a second adjacent one of the integrated circuit stubs, and third conductors to provide signals to an integrated circuit chip. The integrated circuit stubs include first drivers and second drivers coupled to the first, second, and third conductors, wherein the first drivers receive the external signals from the first conductors and drive them onto the second conductors and the second drivers receive signals from the first conductors and drive them onto the third conductors.

Abstract: An active termination for a transmission line comprising a reference impedance, a terminating impedance and a control circuit. The reference and terminating impedances are identical circuits made on the same integrated circuit in close proximity to one another. Both impedances are made of an active and a passive resistor in series. The active resistor is a CMOS transistor operated as a voltage controlled resistor. A control circuit senses the impedance of the reference impedance and generates a control signal to change the impedance of the reference and terminating impedances such that they are made equal to the impedance of the transmission line. An alternate embodiment of the invention comprises an active resistor and a passive resistor in series to form a terminating impedance network. A control circuit senses the voltage on the transmission line and adjusts the active resistor to terminate the transmission line with the correct value of resistance.

Abstract: According to the present invention, a data transmitting/receiving buffer provides an AND 5a for obtaining a logical product of an output enable signal/OE and receiving data RD, and outputting a receiving trigger signal RTG; inverter 6 for inverting the output enable signal/OE; and an AND 5b for obtaining a logical product of an output signal in the inverter 6 and transmitting data TD, and for outputting a receiving trigger signal RTG. It is possible to observe the only receiving signal by observing differential signals D+, D− at the cable side 30 by a receiving trigger signal RTG with an oscilloscope 40. Further, it is possible to observe the only transmitting signal by observing the differential signals D+, D− BY A TRANSMITTNG TRIGGER SIGNAL TTG. Thereby, a data transmitting/receiving buffer can select waveforms of a transmitting signal and a receiving signal to observe the selected waveform.

Abstract: Systems and methods are provided for improving signal propagation. A repeater segments a transmission line into a first and a second line. The repeater includes an inverting amplifier and an equilibration circuit. The inverting amplifier has an input connected to the first line and an output connected to the second line. The amplifier receives and an input signal at a first logic potential and transmits an output signal at an inverted second logic potential during and an active portion of a cycle. The equilibration circuit electrically isolates the first line and the second line and shorts the first line to the second line during and an inactive portion of the cycle. Upon completion of the inactive portion of the cycle, the first line and the second line have substantially equal starting potentials between the first logic potential and the second logic potential.

Abstract: A series of logic clouds is used to distribute and propagate signals traveling a relatively long distance across a data logic circuit fabric. One or more long distance signals originate from an initial logic cloud that may be located on a source data block and pass through a series of logic clouds that may be located on an intermediate data block before passing through a destination logic cloud located on a destination data block. Each logic cloud reads both stabilized logic signals and long distance signals and employs a NAND gate connected with an inverter to perform not only logical operations but also to act as a repeater between the logic clouds. The stabilized logic signals may represent signals that originate from other sources along a given data path.

Abstract: A bus subscriber node (2) having a feed module (10) and means (9) for transmitting and/or receiving information by way of the bus (1) has a switch module (11) which is actuatable by way of a switching logical member (12) and by which the feed module (10) can be connected to the bus (1) or by which the feed module (10) can be separated from the bus (1). The bus subscriber node (2) also has a memory cell (14) and a monitoring member (13) for detecting a current supplied by the feed module (10). The switching logical member (12) is coupled to the memory cell (14) and the monitoring member (13) in such a way that the feed module (10) can be separated from the bus (1) on the basis of an item of information stored in the memory cell (14) or on the basis of a certain current level detected by the monitoring member (13). With the memory cell (14) the bus subscriber node (2) can be configured as a feeding or as a non-feeding bus subscriber node and can be used in communication networks with central and decentral feed.

Abstract: A method and system for high speed bussing in microprocessors and microelectronic devices is disclosed. The method and system implement a type of differential bus with distributed bus pre-charge units designed to decrease bus pre-charge time. The method and system utilize a universal self-tracking clock signal to determine the minimum required bus pre-charge time. The time saved by decreasing the bus pre-charge time can be directly applied to the bus evaluation period thereby increasing system performance and reliability.

Abstract: To provide a pulse transmission line control system that can prevent a malfunction of microcomputers included in an apparatus configured by the microcomputers that have a function of decoding an electrical signal pulse generated from an infrared code sent from an infrared remote control unit. A main microcomputer A (1) controls on/off states of a switch (6) provided in a pulse transmission line (5) and turns on the switch (6) only when a sub-microcomputer B(2) performs a process on the infrared code sent form an infrared remote control unit (3).

Abstract: A glitch suppression circuit has a read pointer and a write pointer that track memory locations. A comparator compares the read pointer and the write pointer and provides a compare signal indicative of a particular memory condition. The glitch suppression circuit includes an offset read pointer and an offset write pointer that track memory locations. An offset comparator compares the read pointer and the write pointer and provides an offset compare signal indicative of the particular memory condition. A timing signal controls a multiplexer for selecting either the compare signal or the offset compare signal and sets a logic flag. The setting of the logic flag may be synchronized to a timing signal.

Abstract: The present invention includes a system for and a method of determining noise characteristics of a circuit of an integrated circuit. The circuit is classified based on its topology and measured circuit parameters. Noise characteristics are retrieved using the circuit classification and circuit parameters to calculate a noise response. Classification and characterization may be performed on each individual input.

Abstract: There are provided a transmission circuit capable of stabilizing high-speed data transfer by driving current, a data transfer control device, and electronic equipment. An HS current driver (transmission circuit) included in a data transfer control device has a current source connected between a first power supply AVDD and a node ND, and switching devices SW1 to SW3, one ends of which are connected to the node ND. The other end of the switching device SW1 is connected to a DP terminal. The other end of the switching device SW2 is connected to a DM terminal. The other end of the switching device SW3 is connected to a DA terminal. The DA terminal is connected to a second power supply AVSS inside or outside the transmission circuit. The transmission circuit is configured so that impedances of each current path from the node ND through the switching devices SW1 to SW3 become substantially equal when the switching device is turned on.

Abstract: An interface circuit for a printer to prevent transmission of an incorrect control signal when power is input into the printer. The interface circuit improves the stability of the printer at the initial state of the rise of power supply voltages, and prevents erroneous operation. After power is input, in a switching control part 110, a flip-flop X23 is reset, a level change of output signals s1-s5 of an input part 100 is detected by a NAND gate X21, and an output signal s9 of the flip-flop X23 is raised. In a switching part 120, when the signal s9 is at low level, output signals s10-s14 are held at high level, and when the signal s9 is at high level, the output signals s1-s5 of the input part 100 are output to an output part 130. Thus, the output signals are held after the power input, and after the input signal rises, the signal transfer function is started, so that the output of incorrect control signals can be prevented, and thereby erroneous operation of a printer can be prevented.

Abstract: An integrated circuit that asymmetrically shields a signal to increase decoupling capacitance is provided. The signal is asymmetrically shielded based on a probability of the signal being at a specific value. Further, a computer system that uses asymmetrically shielding to increase performance is provided. Further, a method for increasing an amount of implicit decoupling capacitance on a circuit through asymmetric shielding is provided. Further, a method to increase component performance by increasing implicit decoupling capacitance is provided.

Abstract: A method is described that involves driving a first current through a line and a termination resistance so that a logical value on the line changes from a first logical value to a second logical value. The method also includes holding the second logical value on the line by driving a second current through the line and the termination resistance where the second current less than the first current. An apparatus is described that includes a driver that drives a first current through a line and a termination resistance so that a logical value on the line changes from a first logical value to a second logical value. The driver holds the second logical value on the line by driving a second current through the line and the termination resistance. The second current is less than said first current.

Abstract: An integrated circuit that preferentially shields a signal to increase decoupling capacitance is provided. The signal is preferentially shielded based on a probability of the signal being at a specific value. Further, a method for increasing an amount of decoupling capacitance on a circuit through preferential shielding is provided. Further, a method to increase system performance by increasing implicit decoupling capacitance is provided.

Abstract: An integrated bus interface circuit for a computer system for communicating between a serial bus and a function device. The bus interface circuit includes a voltage regulator, a bidirectional serial data transceiver, a serial interface engine, and a device controller. The voltage regulator supplies a first power supply voltage (e.g., 3.3 volts) in a first voltage range by using a second power supply voltage (e.g., 5 volts) in a second voltage range. The transceiver converts a plurality of bus-specific data signals (e.g., 3.3V modulated format) into a plurality of interface-specific data signals (e.g., 5V modulated format), and conversely, by using the first and second power supply voltages. The serial interface engine performs an interface between the interface-specific signals and a plurality of device-specific signals (e.g., 5V binary format). The device controller controls the function device in response to the device-specific signals.

Abstract: A semiconductor memory device is provided, which includes a chip enable buffer and an address buffer. The chip enable buffer generates first and second control signals having opposite phases of logic, the first and second control signals enable and disable operations of the semiconductor memory device, respectively. The address buffer includes an input terminal, and a blocking terminal connected to the input terminal, the input terminal receiving an external address signal under control of the first control signal, and the blocking terminal generating an address signal in response to the second control signal. The address buffer further includes a shift detecting circuit connected to the blocking terminal for generating first and second short pulses by detecting shift of the address signal, wherein the pluses are used as signals for reading data of the semiconductor memory device.

Abstract: The present invention is to provide a logic circuit which assures short-circuit current reduction by using a gate which uniquely fixes the level of each node and also reduces leakage current so that the power is turned on and off quickly.

Abstract: In some embodiments, the invention includes a controller that has clock signal transmitters to transmit Clk signals and data signal transmitters to transmit Data signals. Multi-phase producing circuitry includes multiple taps to receive a clock signal and in response thereto to produce phases on the taps. Delay determining circuitry determines relative delays to be provided between the Clk signals and Data signals and to provide signals regarding the relative delays, and delay adjustment circuitry receives the signals regarding relative delays and select amongst the taps to achieve the relative delays between the Clk and Data signals. Other embodiments are described and claimed.

Abstract: A latchless dynamic asynchronous digital pipeline uses control information for a processing stage from the subsequent processing stage as well as stages further down the pipeline. A first function block in a first processing stage is enabled to enter a first evaluate phase and a first precharge phase in response to a first precharge control signal provided by a second, subsequent processing stage which is asserted upon completion of evaluation by the second processing stage and a second precharge control provided by a third processing stage which is asserted upon completion of evaluation by the third processing stage, such that the first evaluate phase is enabled by at least one of the de-assertion of the first precharge control signal and the assertion of the second precharge control signal, and such that the first precharge phase is enabled by the assertion of the first precharge control signal and the de-assertion of the second precharge control signal.

Abstract: A signal transmission apparatus is disclosed for setting delay amounts based on an operational speed. At least some of a plurality of rectangular wave signals transmitted in parallel are individually delayed by a plurality of signal delaying means for different time periods from one another in order to prevent the occurrence of noise. At this point, the delay time in the plurality of signal delaying means are set by time varying means based on the operational speed of a digital circuit which outputs digital data as the rectangular wave signals.

Abstract: An apparatus comprising one or more input/output circuits that may be configured as (i) high voltage tolerant in response to a first state of a control input and (ii) a clamp to a power supply voltage in response to a second state of said control input.

Abstract: A noise suppression circuit for suppressing above-ground noise is disclosed. The noise suppression circuit for suppressing noises includes a first inverter, a second inverter, and a one-shot circuit. The first inverter, connected to an input line, switches at a first voltage value above which a noise-coupling event is suspected. The second inverter, also connected to the input line, switches at a second voltage value above which a full-switch input is assumed. A first transistor is coupled to the input line. A second transistor passes an output of the second inverter to a gate of the first transistor when an output of the one-shot circuit is high. The third transistor holds the gate of the first transistor low when the output of the one-shot circuit is low.

Abstract: An integrated circuit that preferentially shields a signal to increase decoupling capacitance is provided. The signal is preferentially shielded based on a probability of the signal being at a specific value. Further, a method for increasing an amount of decoupling capacitance on a circuit through preferential shielding is provided. Further, a method to increase system performance by increasing implicit decoupling capacitance is provided.

Abstract: An impedance control circuit that reduces the impedance variance when an external impedance generated from an external resistor is matched to internal impedance. In one aspect, an impedance control circuit comprises an external resistor for establishing a first reference voltage; a comparator for comparing the first reference voltage with a second reference voltage and outputting an impedance corresponding to the result of the comparison; and a PMOS current source connected to a constant-voltage source and to the output of the comparator, wherein the PMOS current source generates a current that corresponds to the impedance of the comparator.

Abstract: A bifurcation circuit uses dynamic asP* protocol. to exchange data among three or more FIFOs. Each FIFO contains a plurality of places containing data and a plurality of paths that exchange data between neighboring places. The bifurcator circuit generally comprises a control FIFO, two subordinate FIFOs and a bifurcation path coupled to all three FIFOs. The bifurcator circuit further comprises a chain of data latches coupled to all three FIFOs at the bifurcation path. A data value carried in the control FIFO determines which of the subordinate FIFOs exchanges data with the control FIFO. Each place in the FIFOs contains a set reset flip-flop in which the state of each place is held by a single wire and stabilized by a keeper. A single transistor sets or resets the state of the place. The pulse that changes the state of the control flip-flops also makes the data latches momentarily transparent. The bifurcator circuit is generally capable of a branch or join operations.

Abstract: An electronic device includes a wiring board, and at least one pair of signal lines that is provided on the wiring board in parallel and has an equal length. A chip is mounted on the wiring board and includes at least one differential driver which outputs complementary digital transmit signals to said at least one of lines. A pair of power system lines is provided to supply first and second power supply voltages to the above-mentioned at least one differential driver. The power system lines are parallel to each other and have an equal length.

Abstract: A buffer circuit includes an input for receiving a logic signal, and a transfer circuit for transferring the logic signal from the input to an output of the buffer circuit. The transfer circuit includes at least one logic gate having a trip point sensitive to a supply voltage of the buffer circuit. The buffer circuit further includes a delivery circuit for delivering an inhibit signal having a predetermined duration when the logic signal has a trailing edge and/or leading edge, and an inhibit circuit for inhibiting the transfer circuit and for isolating the output of the buffer circuit from the input of the buffer circuit when the inhibit signal is delivered. A storage circuit holds a logic value of the logic signal at the output of the buffer circuit when the inhibit signal is delivered.

Abstract: An integrated circuit that asymmetrically shields a signal to increase decoupling capacitance is provided. The signal is asymmetrically shielded based on a probability of the signal being at a specific value. Further, a computer system that uses asymmetrically shielding to increase performance is provided. Further, a method for increasing an amount of implicit decoupling capacitance on a circuit through asymmetric shielding is provided. Further, a method to increase component performance by increasing implicit decoupling capacitance is provided.

Abstract: A circuit for reducing the noise associated with a clock signal for a latch based circuit has been developed. The circuit includes a charge control portion that stores charge at a pre-determined time of the clock cycle and a dump control portion that releases the stored current also at a predetermined time of the clock cycle. The charge is released onto the power grid of the system served by the clock signal in synchronization with the operation of the latch.

Abstract: A method for reducing the noise associated with a clock signal for a latch based circuit has been developed. The method includes storing a charge at a pre-determined time of the clock cycle and releasing the stored charge also at a pre-determined time of the clock cycle. The charge is released onto the power grid of the system served by the clock signal in synchronization with the operation of the latch.

Abstract: The signal processing device comprises determining means to supply an output signal having a value representative of a time constant of a part of an input signal having an appreciably exponential form. The determining means comprise first integrating means to supply a first integration signal representative of integration of the input signal in two opposite directions for appreciably equal times. Extraction means connected to the first integrating means supply a value representative of a time constant as a function of the first integration signal. The process comprises integration and extraction steps to supply the value representative of a time constant.

Abstract: A high frequency differential amplifier with a circuit topology which ensures that bias currents of the high transconductance differential transistors with minimum channel length are exactly equal, i.e., each differential transistor carries exactly half of the total current I0 of the differential amplifier. This is achieved by coupling each differential transistor via its own current source to the reference potential. To insure a good match between the current sources, the current source devices are made with long channel lengths. Impedances are coupled between the junctions of each differential transistor pair and its current source to insure good AC gain. For the variable gain differential amplifier the spread in the gain control characteristics is reduced by making the aspect ratio of the first pair of differential transistors larger than that of the second pair of differential transistors.

Abstract: The present invention includes a driving circuit and method for driving signals. An input signal is received by the driving circuit on an input signal line which is connected to a bias circuit for a common voltage level. Two output lines from the driving circuit are driven to the receiver which is capable of using differential output lines or a selected single ended output line. Furthermore, the output lines may be driven to a high impedance selected by the voltage level of the input signal. The receiver of the output lines may be a SCSI device using multimode terminators which include low voltage differential and a single ended mode.