Abstract: A dental usage monitoring system having a dental appliance, a sensor unit having at least one sensor attached to the dental appliance, a power supply attached to the dental appliance, and an analyzer. The at least one sensor attached to the dental appliance is configured to collect data related to usage of the dental appliance. An analyzer in communication with the sensor and is configured to determine usage of the dental appliance based upon the collected data. The dental usage monitoring system can include a base module configured to receive collected data, transmit data to the analyzer, and recharge the sensor unit. The base module can be further configured to calibrate the collected data. The sensor unit can be embedded in the dental appliance or coupled to the dental appliance. The sensor unit may be encased in a protective coating.

Abstract: A line powered telephoe is disclosed in which the telephone is not powered from a separate external source. The improved pay telephone is powered solely by loop current available on the telephone line from the central office. A rechargeable battery is provided to store excess loop current to enable operation of the pay telephone when not off-hook to the central office. Power consumption by components of the telephone is minimized by shutting down unnecessary functions on a selective basis to ensure that sufficient excess loop current is available to recharge the battery. In addition, an improved switched-capacitor circuit is disclosed to enable storage of electricity at a voltage potential higher than the off-hook line voltage to enable firing of standard high voltage relays for coin collection and coin return.

Abstract: Voice recording apparatus includes full duplex communication between the operator`s telephone set and the PBX switching matrix, and digital signal recording circuitry, for selectably presenting the operator's actual voice or the recorded voice message to the PBX in response to operator selection.