Abstract: A telephone communications interface adapted to provide a data link for receiving and transmitting serial data via FSK modulated carrier signals over telephone lines to a computer. An operational amplifier in a duplexer circuit has a variable impedance feedback circuit, which is automatically adjusted by a computer subroutine to adjust the amplifier gain, so as to compensate for variations in the telephone company line impedance. The gain is adjusted to minimize the amplitude of any transmitted carrier signal, which might appear at the input of the conventional band pass filter for the receiver carrier signal.

Abstract: A telephone subscriber's terminal equipment, which is part of a telecommunications network, is disclosed which includes ring suppress circuitry that prevents a ringing signal, which indicates the presence of an incoming call, from dinging the bell in the terminal equipment until the calling party is identified. The ring suppress circuitry also permits required loop current through the subscriber's terminal equipment to provide subscriber billing protection for the telephone company. The terminal equipment includes a microprocessor that detects the ringing signal and activates a relay in the ring suppress circuitry to prevent the terminal bell from dinging. Suppression of the ding is attributable to two back-to-back zener diodes connected in series with the relay contact and between the tip and ring conductors of the terminal equipment.

Abstract: A horological instrument includes a liquid crystal electro-optical display which simulates the movement of hands about a center by activating circumferentially spaced radial conductive segments. Generally, for the liquid crystal material between two corresponding segments to be activated an electrical potential must be applied between the segments which is, typically to achieve full brightness, substantially greater than the activation voltage of the liquid crystal material. The present invention effects activation of a selected segment-hand by applying an electrical potential, predetermined greater than the activation voltage, between the selected segment-hand and a corresponding segment or electrode.

Abstract: A horological instrument includes a liquid crystal electro-optical display which simulates the movement of hands about a center by activating circumferentially spaced radial conductive segments. Generally, for the liquid crystal material between two corresponding segments to be activated an electrical potential must be applied between the segments which is, typically to achieve full brightness, substantially greater than the activation voltage of the liquid crystal material. The present invention effects activation of a selected segment-hand by applying an electrical potential, predetermined greater than the activation voltage, between the selected segment-hand and a corresponding segment or electrode.