International Teleservice Corporation

Technology Service Group

Thomas D Young

Marcus K Davenport

Stephen H Strode

Richard K Shipman

Allen W Vogl

Steven E Betts

Scott G Turner

A cellular paystation system has a transceiver, paystation and an interface. The cellular paystation system operates to prevent return dial tone fraud by providing from the interface a first dial tone to a calling party using the paystation when an off-hook condition is first detected at the paystation by the interface, and then preventing another dial tone from being provided to the calling party until an on-hook condition of the calling party is detected by the interface at the paystation.

Method and apparatus for preventing return dial tone fraud in a cellular

An integrated customer owned coin operated telephone (COCOT) and regulated paystation telephone system permits the functionality of the paystation to be remotely programmed, in order to increase the versatility of the paystation in either mode of operation. The integrated paystation telephone system includes a central microprocessor coupled with a memory that stores the firmware for operating the paystation telephone. Circuitry is provided under the control of the microprocessor to operate such functions as the power control and coin relay (the relay which excepts or refunds a deposited coin) in either mode of operation. The paystation telephone system is remotely configured to operate in either the COCOT or regulated mode without requiring any hardware changes. Because of the remote configuration of the paystation telephone system, various features can be programmed, increasing the versatility of the paystation.

Integrated cocot and regulated paystation telephone system

Increased power to operate a paystation coin relay is derived from the tip/ring pair by means of a power boost circuit, which is controllably coupled to the tip/ring pair when the coin relay is to be fired. To fire the coin relay, a line coupling relay circuit is energized, so as to apply the tip/ring line voltage to a D.C.-to-D.C. converter, the output of which is coupled to current storage (capacitor) circuit. The output of the current storage circuit is coupled to a first switch circuit and monitored by a comparator. The first switch circuit has an output coupled in circuit with the coin relay. In response to the comparator detecting that the current storage circuit has accumulated sufficient electrical energy to fire the coin relay, the comparator enables the first switch circuit, so that the output of the current storage circuit is applied to the coin relay, thereby firing the coin relay, to either collect accumulated coins or return the coins to the paystation user, depending upon a controllably established coin relay current flow path to the coin relay winding. The output of the comparator is further coupled through a delay circuit to a second transistor switch circuit which is coupled to the line coupling relay. The second switch circuit is operative to apply a de-energizing potential to the line relay a prescribed period of time subsequent to the firing of the coin relay, thereby returning the line relay to its normal state.

Circuit for firing paystation coin relay using power derived from

A call progress circuit for both a customer owned, coin operated telephone and a regulated telephone is provided that does not mute the paystation's transmitter, so that voice signals from the calling party may be heard by the called party, thereby preventing an answering party from hanging up prematurely. The call progress circuit employs a transmitter-sourced audio signal discriminator which monitors audio signals placed on the line from the called station, the calling paystation and a central office, and controllably removes or subtracts out those audio signals that originate at the paystation transmitter. The discriminator includes a pair of tunable bandpass filters respectively associated with a telephone line receiver and the paystation transmitter circuit. Coupled to these filters is an audio spectrum scanner which sequentially adjusts the sensitivity characteristics of the filters. Q-adjustment of each filter is effected by controlling the value of a time constant setting resistor that determines the transfer function of each of a set of filter stages, with tuning of the filter's center frequency being a function of the duty cycle of a variation in each stage's resistor value. The output of the line receiver filter is coupled through a transmitter-modifier representative of the effects of the circuit components and the line, so as to adjust transmitter-sourced audio signals to a level that will permit them to be correctly excised from the receiver filter's output.

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Snellville, GA, United States of America

Thomas D Young