Abstract: A dual motor speed control circuit for providing independent speed control of two motors in a laser scanning device is disclosed herein. This apparatus utilizes a single input signal having variable frequency and duty cycle components. The speed of the first motor is controlled by utilizing the frequency component of said input signal while the speed of the second motor is controlled by utilizing the frequency and duty cycle components of said input signal. Specifically, a DC signal is generated that is dependent upon the duty cycle component of said input signal and said DC signal is utilized to offset the speed of the second motor from the speed value as determined by the frequency component of said input signal.

Abstract: An improved and simplified voltage sensitive switching unit for opening a telephone subscriber pair at the line of demarcation for purposes of conducting line tests of the pair from the telephone central office to determine the state of the line. Relatively complex prior art circuitry is replaced by a combination of inexpensive solid state devices which eliminates the need for a prior art combination of diode bridge and transistor switching network.

Abstract: An improved testing and reporting system for individual telephone subscriber circuits providing improved fault location technology together with major reduction in subscriber loop maintenance and repair operating costs. Provision is made for the testing of lines too remote for direct testing by resort to distally located test units controlled from a central office.