Abstract: For use in a processor supervisory circuit, a power-on reset circuit, a method of producing a power-on reset ("RESET") signal and a power supply including the circuit. The circuit includes: (1) an adaptive, nonlinear voltage divider having a voltage input and a voltage output, the divider dividing an unscaled, unregulated voltage received at the voltage input by a factor that varies a function of the unscaled, unregulated voltage to produce a scaled, unregulated voltage at the voltage output and (2) a comparison circuit for comparing the scaled, unregulated voltage with a scaled, regulated voltage to produce the RESET signal when the scaled, regulated voltage exceeds the scaled, unregulated voltage, the divider being adaptive and nonlinear to ensure that the comparison circuit continuously produces the RESET signal when the scaled, regulated voltage exceeds the scaled, unregulated voltage and thereby avoid premature activation of a processor couplable to the power-on reset circuit.

Abstract: For use with a telecommunications network, circuit for, and method of, detecting telephone line status and a telephone instrument embodying the same. The circuit includes: (1) a high-impedance amplifier, couplable to the telecommunications network, for providing DC voltage representing a differential line voltage between tip and ring conductors of the telecommunications network and (2) a pulse-generation circuit, coupled to an output of the amplifier, for generating a signal having first and second states, the signal assuming the second state for a period of time inversely proportional to the differential line voltage between the tip and ring conductors.

Abstract: A circuit for, and method of, reducing cross-coupled interference between first and second telephone lines of a multi-line telephone instrument and a telephone instrument containing the same. The circuit includes: (1) a first differential input amplifier having first tip and ring inputs coupled to conductors of the first telephone line and first tip and ring shunt resistors coupling the first tip and ring inputs to a signal reference of the telephone instrument and (2) a second differential input amplifier having second tip and ring inputs coupled to conductors of the second telephone line and second tip and ring shunt resistors coupling the second tip and ring inputs to the signal reference, the first and second tip and ring shunt resistors decreasing a common mode input resistance of the first and second differential input amplifiers, thereby attenuating cross-coupled interference common to both of the first and second telephone lines.