Abstract: A measuring probe measures a parameter with a sensor. The sensor provides a sensor output signal related to a measured value. An amplifier section receives the sensor output signal and provides an amplifier output signal. An integrator has an input and an integrator output related to an integration of the input. Switching circuitry receives the amplifier output signal and a reference signal and has an output connected to the input of the integrator. Controller circuitry coupled to the switching circuitry connects the amplifier output to the integrator input during a sampling time, and the reference signal to the integrator input during a conversion time. The conversion time is related to the sensor output signal and is measured to obtain a digital representation of the sensor output.

Abstract: Telephone use control apparatus in which a microcontroller controls the functions of the apparatus and in which the apparatus is provided with batteries to maintain power to the microcontroller and circuitry associated therewith when the the telephone is in operation, and means for providing power from the incoming telephone line to run the apparatus when the telephone is not in use. The incoming power from the telephone line is also usable to recharge the batteries. In addition, the case for the apparatus is made to mount the electrical components without the use of screws, and to permit the assembly of the various parts of the case, also without screws.