Communication between a telephone and a computer system

• US 5,850,436 A
• Filed: 08/23/1996
• Issued: 12/15/1998
• Est. Priority Date: 08/23/1996
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.), PureSpeech, Inc. (Koninklijke Philips N.V.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Weinstein, Lee D., Rosen, P. Bradley, Dash, Glen R., Bromberg, Michael A.
• Primary Examiner(s): Zele, Krista
• Assistant Examiner(s): SAINT SURIN, JACQUES M
• Application Number:
  US08/702,151
• Time in Patent Office: 844 Days
• Field of Search: 379/377, 379/93.09, 379/67, 379/93.01, 379/88, 379/100.16, 379/162, 379/211, 379/212, 379/350, 379/373, 379/89, 379/379, 379/112, 455/402, 455/400
• US Class Current: 379/377
• CPC Class Codes: H04M 1/715 using two or more extensions per line cordless telephones H04M1/725
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 9/02 involving a common line for all parties

Abstract

A method and apparatus provide communication in a telephone system connected to an external phone line, wherein the telephone system has a telephone line, a telephone, a phone interface unit coupled to the telephone and the telephone line, a computer system, and a computer interface unit coupled to the computer system and the telephone line. A bias voltage on the telephone line is detected to determine if the telephone is on-hook or off-hook, a ringing voltage on the telephone line is detected to determine if an external call is incoming, and a first carrier transmitted by the phone interface unit is detected. A second carrier is transmitted using the computer interface unit under control of the computer system. Detection of the bias voltage, ringing voltage, and/or first carrier is communicated to the computer system. An off-hook condition is indicated if the line bias voltage is less than an off-hook bias threshold voltage. An incoming ring is indicated if the ringing voltage has an amplitude greater than a first voltage and a frequency in the range of a ring frequency. The first carrier is indicated as being present if a signal is detected at a first carrier center frequency and having an amplitude greater than a first carrier threshold voltage. The second carrier is indicated as being present if a signal is detected at a second carrier center frequency and having an amplitude greater than a second carrier threshold voltage.

Claims

1. A method of communicating information in a telephone system connected to an external phone line, the telephone system having a telephone line, a telephone, a phone interface unit coupled to the telephone and the telephone line, a computer system, and a computer interface unit coupled to the computer system and the telephone line, the method comprising the steps of:

(a) detecting as an event any of (1) a bias voltage on the telephone line to determine if the telephone is on-hook or off-hook, (2) a ringing voltage on the telephone line to determine if an external call is incoming, and (3) a first carrier having a first frequency transmitted by the phone interface unit in response to the telephone being off-hook;

(b) transmitting a second carrier using the computer interface unit under control of the computer system to control connection of the telephone to the telephone line;

(c) communicating detection of the bias voltage, ringing voltage, or first carrier to the computer system; and

(d) activating a flash-hook indication on the telephone line if the line bias voltage is detected, then not detected for less than a predetermined period of time, then detected again.

2. The method of claim 1, further comprising the step of:

detecting the flash-hook indication.

3. The method of claim 2, further comprising the step of:

notifying the computer system of a flash-hook event if the flash-hook indication is detected.

4. A method of communicating information in a telephone system connected to an external phone line, the telephone system having a telephone line, a telephone, a phone interface unit coupled to the telephone and the telephone line, a computer system, and a computer interface unit coupled to the computer system and the telephone line, the method comprising the steps of:

(a) detecting as an event any of (1) a bias voltage on the telephone line to determine if the telephone is on-hook or off-hook, (2) a ringing voltage on the telephone line to determine if an external call is incoming, and (3) a first carrier having a first frequency transmitted by the phone interface unit in response to the telephone being off-hook;

(b) transmitting a second carrier using the computer interface unit under control of the computer system to control connection of the telephone to the telephone line;

(c) communicating detection of the bias voltage, ringing voltage, or first carrier to the computer system; and

(d) indicating presence of the first carrier if a signal is detected having a first carrier center frequency and having an amplitude greater than a first carrier voltage.

5. The method of claim 4, wherein the first carrier center frequency is above 270 kHz.

6. The method of claim 4, wherein the first carrier frequency is about 310 kHz.

7. The method of claim 4, wherein the first carrier voltage is about 4 volts.

8. A method of communicating information in a telephone system connected to an external phone line, the telephone system having a telephone line, a telephone, a phone interface unit coupled to the telephone and the telephone line, a computer system, and a computer interface unit coupled to the computer system and the telephone line, the method comprising the steps of:

(a) detecting as an event any of (1) a bias voltage on the telephone line to determine if the telephone is on-hook or off-hook, (2) a ringing voltage on the telephone line to determine if an external call is incoming, and (3) a first carrier having a first frequency transmitted by the phone interface unit in response to the telephone being off-hook;

(b) transmitting a second carrier using the computer interface unit under control of the computer system to control connection of the telephone to the telephone line;

(c) communicating detection of the bias voltage, ringing voltage, or first carrier to the computer system; and

(d) indicating presence of the second carrier if a signal is detected having a second carrier center frequency and having an amplitude greater than a second carrier voltage.

9. The method of claim 8, wherein the second carrier center frequency is above 270 kHz.

10. The method of claim 8, wherein the second carrier center frequency is about 485 kHz.

11. The method of claim 8, wherein the second carrier voltage is about 4 volts.

12. A telephone system comprising:

a telephone line for connection to an external phone line;

a telephone coupled to the telephone line;

a phone interface unit coupled to the telephone and the telephone line;

a computer system;

a computer interface unit coupled to the computer system and the telephone line;

a first detector for detecting a bias voltage on the telephone line to determine if the telephone is on-hook or off-hook;

a second detector for detecting a ringing voltage on the telephone line to determine if an external call is incoming; and

a third detector for detecting a first carrier having a first frequency transmitted by the phone interface unit in response to the telephone being off-hook; and

wherein the computer interface unit transmits a second carrier under control of the computer system to control connection of the telephone to the telephone line; and

wherein the computer interface unit communicates detection of the bias voltage, ringing voltage, and first carrier to the computer system.

13. The telephone system of claim 12, wherein the phone interface unit has means responsive to the second carrier for isolating the telephone from the telephone line if the second carrier is transmitted.

14. The telephone system of claim 12, wherein the phone interface unit connects the telephone to the telephone line if the second carrier is not transmitted.

15. The telephone system of claim 12, wherein the computer interface unit notifies the computer system that the telephone is about to transmit voice data if the first carrier is detected.

16. The telephone system of claim 12, wherein the computer interface unit notifies the computer system that the telephone is off-hook on the telephone line if the line bias voltage is detected.

17. The telephone system of claim 12, wherein the computer interface unit notifies the computer system that the telephone is on-hook on the telephone line if the line bias voltage is not detected.

18. The telephone system of claim 12, wherein the computer interface unit notifies the computer system of an external phone call event if the ringing voltage is detected on the telephone line.

19. The telephone system of claim 12, wherein the computer system includes a flash-hook detector for activating a flash-hook indication if the line bias voltage is detected, then not detected for less than a predetermined period of time, then detected again.

20. The telephone system of claim 12, wherein the computer system is executing a communication software program, and wherein the computer system includes a device driver for translating the bias voltage into a telephony application programming interface event that is posted to the communication software program.

21. The telephone system of claim 12, wherein the computer system is executing a communication software program, and wherein the computer system includes a device driver for translating the ringing voltage into a telephony application programming interface event that is posted to the communication software program.

22. The telephone system of claim 12, wherein the computer system is executing a communication software, and wherein the computer system includes a device driver for translating the first carrier into a telephony application programming interface event that is posted to the communication software program.

23. The telephone system of claim 12, wherein the computer system is executing a communication software, and wherein the computer system includes a device driver for translating the bias voltage, ringing voltage, and first carrier into telephony application programming interface events that are posted to the communication software.

24. The telephone system of claim 12, wherein the computer interface unit is responsive to detection of the line bias voltage, indicating an off-hook condition if the line bias voltage is less than an off-hook bias voltage.

25. The method of claim 24, wherein the off-hook bias voltage is about 24 volts.

26. The telephone system of claim 12, wherein the computer interface unit indicates an incoming ring if the ringing voltage has an amplitude greater than a first voltage and a frequency in the range of a ring frequency.

27. The telephone system of claim 26, wherein the first voltage is about 50 volts and the ring frequency is about 15-68 Hz.

28. The telephone system of claim 12, wherein the first carrier is transmitted over the telephone line.

29. The telephone system of claim 28, wherein the second carrier is transmitted over the telephone line.

30. The telephone system of claim 12, wherein the computer interface unit indicates presence of the first carrier if a signal is detected having a first carrier center frequency and having an amplitude greater than a first carrier voltage.

31. The telephone system of claim 30, wherein the first carrier center frequency is above 270 kHz.

32. The telephone system of claim 30, wherein the first carrier frequency is about 310 kHz.

33. The telephone system of claim 30, wherein the first carrier voltage is about 4 volts.

34. The telephone system of claim 12, wherein the computer interface unit indicates presence of the second carrier if a signal is detected having a second carrier center frequency and having an amplitude greater than a second carrier voltage.

35. The telephone system of claim 34, wherein the second carrier center frequency is above 270 kHz.

36. The telephone system of claim 34, wherein the second carrier center frequency is about 485 kHz.

37. The telephone system of claim 34, wherein the second carrier voltage is about 4 volts.