Telephone inadvertent off-hook condition detector

• US 5,592,529 A
• Filed: 09/29/1994
• Issued: 01/07/1997
• Est. Priority Date: 09/29/1994
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Linsker, Ralph
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Shankar, Vijay
• Application Number:
  US08/314,999
• Time in Patent Office: 831 Days
• Field of Search: 379/1, 379/27, 379/28, 379/32, 379/34, 379/377, 379/381, 379/418, 379/424
• US Class Current: 379/32.04
• CPC Class Codes: H04M 1/82 Line monitoring circuits for call progress or status discrimination for detecting caller identity H04M1/573
• CPC Class Codes: H04M 3/14 Signalling existence of persistent "off-hook" condition

Abstract

An inadvertent-off-hook-condition detecting apparatus for use with a telephone connected to a telephone system is described. The telephone has a hookswitch which connects the voice network of the telephone system across the input lines to the telephone when the hookswitch is in an off-hook position, and which disconnects the voice network from the telephone input lines when the hookswitch is in an on-hook position. The inadvertent-off-hook-condition detecting apparatus has detecting circuit coupled to the telephone for detecting a prespecified signal indicating that the local or remote party wishes to continue the telephone conversation; a timer coupled to the detecting circuit and to the telephone for determining whether the elapsed time since the most recent of the events comprising (1) existence of an on-hook condition and (2) detection of the prespecified signal, is in excess of a prespecified time interval; and an output generator coupled to the timer for producing an output signal indicative of whether the prespecified time interval has been exceeded.

Claims

1. An apparatus for use with a telephone connected to a telephone system, said telephone of said telephone system having means for a user to generate a user generated reset signal, comprising:

said telephone having a hook status selected from a group consisting of on-hook and off-hook,

a detector, having means for coupling to said telephone, for detecting said user generated reset signal;

an indicator of said hook status having means for coupling to said telephone, for producing a hook signal;

a timer, having means for coupling to said telephone, said timer producing a timer signal if and only if said telephone is continuously off-hook for greater than an off-hook time and said user generated reset signal is not detected by said detector within a reset time;

an output signal generator coupled to said timer for producing an output signal;

an auxiliary control for providing said user generated reset signal;

an alarm coupled to said timer;

if said telephone is continuously off hook for greater than said off-hook time and said reset signal is not received within said reset time said telephone is determined to be inadvertently off-hook;

a re-hook means to place said telephone in an on-hook status;

an alert means coupled to said timer for generating an alert signal and wherein if said timer produces said timer signal, said alert means generates an alert signal;

combining means coupled to said detector, said indicator and said timer.

2. An apparatus according to claim 1 wherein said reset signal is a tone signal.

3. An apparatus according to claim 1, wherein said reset signal is a DTMF signal.

4. An apparatus according to claim 1, wherein said reset signal can be produced by another telephone connected to said telephone system.

5. An apparatus according to claim 1 wherein said telephone system includes a voice network coupled to said detector.

6. An apparatus according to claim 1 wherein said telephone includes a hook switch coupled to said indicator.

7. An apparatus according to claim 1 wherein said re-hook means is coupled to said output signal generator.

8. An apparatus according to claim 1 wherein said alert signal is an audible sound.

9. An apparatus according to claim 1 wherein said user is selected from the group consisting of a user of said telephone, and a user of another telephone coupled to said telephone system and in telephonic communication with said telephone.

10. An apparatus according to claim I wherein said off-hook time is equal to said reset time.

11. A telephone for connection to a telephone system, said telephone having a hook status selected from a group consisting of on-hook and off-hook, said telephone or said telephone system having a means for generating a user generated reset signal comprising:

a detector for detecting said reset signal;

an indicator of said hook status for producing a hook signal;

a timer for producing a timer signal if and only if said telephone is continuously off-hook for greater than an off-hook time and said reset signal is not detected by said detector within a user generated reset time;

an output signal generator coupled to said timer for producing an output signal;

an alarm coupled to said timer;

an auxiliary control for providing a user generated reset signal;

an alert means coupled to said timer for generating an alert signal and wherein if said timer produces said timer signal, said alert means generates an alert signal; and

a combining means coupled to said detector, said indicator and said timer; and

if said telephone is continuously off-hook for greater than said off-hook time and said reset signal is not received within said user generated reset time said telephone is determined to be inadvertently off-hook;

further including a re-hook means to place said telephone in an on-hook status; and

said re-hook means is coupled to said output signal generator.

12. A telephone according to claim 11, wherein said reset signal is a tone signal.

13. A telephone according to claim 11, wherein said reset signal is a DTMF signal.

14. A telephone according to claim 11, wherein said reset signal can be produced by another telephone connected to said telephone system.

15. A telephone according to claim 11 wherein said telephone system includes a voice network coupled to said detector.

16. A telephone according to claim 11 wherein said telephone includes a hook switch coupled to said indicator.

17. A telephone according to claim 11 wherein said alert signal is an audible sound.

18. A telephone according to claim 11 wherein said user is selected from the group consisting of a user of said telephone and a user of another telephone coupled to said telephone system and in telephonic communication with said telephone.

19. A telephone according to claim 11 wherein said off-hook time is equal to said reset time.