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

• US 5,818,916 A
• Filed: 06/20/1995
• Issued: 10/06/1998
• Est. Priority Date: 10/19/1993
• Status: Expired due to Fees

• Current Assignee: Quortech Global Solutions Incorporated
• Original Assignee: Technology Service Corporation, Inc.
• Inventors: Young, Thomas D., Vogl, Allen W., Turner, Scott G., Betts, Steven E.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Shankar, Vijay
• Application Number:
  US08/493,217
• Time in Patent Office: 1,204 Days
• Field of Search: 379/58-63, 379/144, 379/145, 379/188, 379/189, 379/200, 379/112, 379/132, 379/146, 379/155, 455/403, 455/406, 455/407, 455/550, 455/564, 455/565
• US Class Current: 379/145
• CPC Class Codes: H04M 15/47 Fraud detection or prevention means
• CPC Class Codes: H04M 17/02 Coin-freed or check-freed systems , e.g. mobile- or card-operated phones, public telephones or booths
• CPC Class Codes: H04M 2215/0148 Fraud detection or prevention means
• CPC Class Codes: H04M 2215/32 Involving wireless systems
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

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.

Claims

1. In a cellular paystation system having a cellular transceiver communicating with a cellular network, a standard paystation, and an interface providing simulated dial tones to the standard paystation, a method of operating the cellular paystation system to prevent return dial tone fraud, the method comprising the steps of:

providing from the interface a first simulated dial tone to a calling party using the standard paystation to place a first call through the cellular network when an off-hook condition is first detected at the standard paystation by the interface;

preventing a second call from being placed by the calling party through the cellular network until an on-hook condition of the calling party at the standard paystation is detected by the interface.

2. A method according to claim 1 wherein the step of preventing, further comprises the steps of:

reading a bit stream from the transceiver;

determining when a status indicator in the bit stream indicates an end of call signal from the transceiver;

disabling dual tone multi-frequency signalling for the interface when the end of a call signal is detected;

waiting for the calling party to go on-hook before re-enabling dual tone multi-frequency signalling.

3. A method according to claim 2, further comprising the steps of:

determining when the calling party has gone off-hook; and

providing from the interface another dial tone to the calling party indicating that another call can be placed.

8. A method according to claim 1, wherein the step of preventing operates by preventing a second simulated dial tone from being provided to the calling party until the on-line condition of the calling party at the paystation is detected by the interface.

4. A cellular paystation system, comprising:

a cellular transceiver communicating with a cellular network;

an interface directly coupled to said transceiver for providing simulated dial tones;

a standard paystation directly coupled to said interface over a tip/ring conductor pair; and

wherein said interface includes means for providing from the interface a first simulated dial tone to a calling party using the standard paystation to place a first call through the cellular network when an off-hook condition is first detected at the standard paystation by the interface and means for preventing a second call from being placed by the calling party through the cellular network until an on-hook condition of the calling party at the standard paystation is detected by the interface, whereby return dial tone fraud is prevented.

5. A system according to claim 4, further comprising:

means for reading a bit stream from the transceiver;

means for determining when a status indicator in the bit stream indicates an end of call signal from the transceiver;

means for disabling dual tone multi-frequency signalling for the interface when the end of a call signal is detected; and

means for waiting for the calling party to go on-hook before re-enabling dual tone multi-frequency signalling.

6. A system according to claim 5, further comprising:

means for determining when the calling party has gone off-hook; and

means for providing from the interface another dial tone to the calling party indicating that another call can be placed.

7. A system according to claim 4, wherein said means for preventing prevents said second call from being placed when a first call attempt by the calling party is unsuccessful due to one of:

no answer by a called party;

called party busy;

cellular network busy; and

a network failure.

9. A system according to claim 4, wherein said means for preventing a second call from being placed by the calling party includes means for preventing a second simulated dial tone from being provided to the calling party.