Abstract: A coin validation mechanism for evaluating coins and the like inserted therein and for validating acceptable coins includes a coin chute defining a coin path and a sensor for evaluating the type of material of which the object in the coin chute is made of. The sensor for evaluating includes a coil sensor positioned adjacent the coin path and a non-resonant electrical circuit for operation of the coil sensor. The coin validation mechanism also includes a light source for directing light across the coin path and a light sensor for sensing light directed across the coin path. An electronic unit is provided for evaluating an electromagnetic perturbation caused by an object moving past the coil sensor and for determining the amount of light blocked by the object in the coin path by comparing the amount of light sensed by the light sensor with the object in the coin with the amount of light sensed by the light sensor in the absence of an object in the coin path.

Abstract: A coin box monitoring circuit for use in pay telephones, providing coin detection, coin volume totalization, and full coin box signaling to the telephone central office. An included coin chute assembly has three channels that cause nickels, dimes, and quarters to pass through specific locations within each channel. Light sources and light detectors detect the passage of coins. A microprocessor is utilized to control the light sources, monitor the detectors, and volumetrically count the coins passing through the coin chute. On reaching a full condition, a microprocessor then controls a relay to signal that the predetermined coin box level has been reached.

Abstract: A circuit operated in response to deposit of a coin through a trigger switch to selectively operate one of a plurality of signal generators. When coins are deposited through said coin trigger switch, blocking light from a light source to a light detection means, an associated signal driver activates a selected tone signal generator.

Abstract: A trigger switch for use in coin operated devices and particularly in telephone paystations consisting of a plurality of parallel channels each including one or more openings through which a light beam passes. Deposit of coins in the appropriate channels blocks one or more light beams passing through the openings causing detection of the light blockage by associated light detectors to operate to give an indication of the quantity and value of coins deposited through the coin channels. A common trigger mechanism is also included and operates in response to deposit of any coins through the trigger switch, to provide operation of an associated coin relay.

Abstract: A coin relay adapted for use with an associated coin hopper mechanism particularly adapted for use in a microcomputer based deregulated paystation. The relay requires only minimum voltages to operate with the associated coin relay operate and release timing controlled by an assoicated microcomputer.

Abstract: A paystation circuit that monitors coin battery signals, hookswitch detect signals and initial rate conditions to provide proper reset signals to the totalizer circuit enabling and/or disabling the dial keypad in order to prevent fraudulent paystation usage.

Abstract: A paystation telephone level control system is disclosed including a telephone receiver driven by a local amplifier and wherein two sets of attenuating resistors, a coarse attenuation set and a fine attenuation set, interface with connectable terminals of a binary control crosspoint switch. The presence or absence of coin tones and dialing tones are detected and the crosspoint switch discretely controlled by their presence to effect discrete levels of attenuation of signals fed to the receiver. In addition, the lever of attenuation during voice communications is a function of a pre-adjusted attenuation and a user selection.

Abstract: A ground detect circuit for use in telephone paystation consisting of a comparator circuit which compares the voltage across a telephone transmitter included in the paystation to prevent users from fraudulent use of the instrument by grounding the handset transmitter to signal the central office that initial rate deposit has been made when in fact it has not. The ground detect circuit upon detecting the presence of ground at the transmitter generates a signal which can be utilized to disable an associated calling device.

Abstract: In a hold circuit including a relay normally latched and connecting the hold circuit to a subscriber telephone line, a first hold release circuit outputs a trigger signal to a silicon controlled rectifier turning on the rectifier responsive to a sensed drop in line potential, thereby providing an electrical path for the discharge of a capacitor. The capacitor discharges through the coil of the relay unlatching the relay and releasing the hold circuit from the line. The hold circuit is also arranged to be released by a second hold release circuit which outputs a trigger signal to the silicon controlled rectifier responsive to a pre-arranged timing interval.

Abstract: In a hold circuit including a silicon controlled rectifier (SCR) normally turned on and connecting the hold circuit to a subscriber line, a first hold release circuit outputs a trigger signal to a transistor turning off the transistor and disconnecting a line seizing network. A second hold release circuit outputs a trigger signal to a second transistor responsive to the line seizing network being disconnected. The second transistor connects a load resistor across the SCR dropping the holding current flowing through the SCR causing it to turn off. The second hold release circuit is also arranged to output its trigger signal to the second transistor responsive to a pre-arranged timing interval.

Abstract: In a telephone substation employing a dual tone multi-frequency signal generator, the common switch functions of disabling the transmitter and muting the receiver are performed by transistor devices responsive to a control signal produced by the signal generator. A bias voltage provided by the transistor device associated with the transmitter prevents dialing signals from reverse biasing the transistor device associated with the receiver and defeating receiver muting.

Abstract: In a hold circuit connectable to a subscriber telephone line, a silicon controlled rectifier is turned on by a user operated momentary pushbutton connecting the positive side of the line to the hold circuit. A comparator circuit sensing the initial value of the loop voltage, turns on a transistor and connects a line seizing network across the subscriber line.

Abstract: In a hold circuit connectable to a subscriber telephone line, a line voltage storage capacitor is momentarily connected to the subscriber line charging to line potential and providing trigger current to a silicon controlled rectifier. When sufficient trigger current is gained the silicon controlled rectifier turns on discharging the capacitor through a latching relay coil and a transistor, thereby turning on the relay and connecting the hold circuit. The transistor is turned on by a bias voltage from the capacitor when the silicon controlled rectifier is turned on.

Abstract: An improved loudspeaking substation circuit employing a dual-tone multi-frequency signal generator wherein output tone levels are regulated by the substation transmission circuit when operating in either a loudspeaker or handset mode. The circuit further provides for preventing acoustic feedback and self-oscillation between the loudspeaker and handset transmitter while transferring between either mode.