The DS75154 is a quad monolithic line receiver designed to satisfy the requirements of the standard interface between data terminal equipment and data communication equipment as defined by EIA Standard RS-232C. Other applications are in relatively short, single-line, point-to-point data transmission systems and for level translators. Operation is normally from a single 5V supply; however, a built-in option allows operation from a 12V supply without the use of additional components. The output is compatible with most TTL and LS circuits when either supply voltage is used. In normal operation, the threshold-control terminals are connected to the VCC1 terminal, pin 15, even if power is being supplied via the alternate VCC2 terminal, pin 16. This provides a wide hysteresis loop which is the difference between the positive-going and negative-going threshold voltages. In this mode, if the input voltage goes to zero, the output voltage will remain at the low or high level as determined by the previous input.