Method and apparatus for automatically switching between pulse code and DTMF signals generated by a telephone

• US 5,369,697 A
• Filed: 04/30/1993
• Issued: 11/29/1994
• Est. Priority Date: 04/30/1993
• Status: Expired due to Term

• Current Assignee: Boston Technology
• Original Assignee: Boston Technology
• Inventors: Hemmings, David F., Gergacz, David S., Murray, John P.
• Primary Examiner(s): Dwyer, James L.
• Assistant Examiner(s): Shehata, M. W.
• Application Number:
  US08/054,265
• Time in Patent Office: 578 Days
• Field of Search: 379/359, 379/360, 379/361, 379/372, 379/377, 379/386, 379/27
• US Class Current: 379/361
• CPC Class Codes: H04M 1/30 Devices which can set up and transmit only one digit at a time
• CPC Class Codes: H04M 3/02 Calling substations, e.g. by ringing selective calling H04Q

Abstract

Dual tone multifrequency (DTMF) signals are automatically generated by a telecommunications device after a telephone number is called. The signals generated to call the telephone number are determined by a manually operated switch indicating pulse code signal generation or dual tone multifrequency signal generation. It is determined that the telephone number has been dialed by detecting a ring-back signal, voice frequency signals, DTMF signals, or data stream signals. Alternatively, if a predetermined period of time, such as ten seconds, passes without the user pressing a number on the keypad, it may be assumed that the telephone number has been dialed. Upon detecting one of these signals or the passage of time, the telecommunications device is controlled to generate only dual tone multifrequency signals for communication with automated services, such as voicemail, telephone banking, reservation systems, etc.

Claims

1. An apparatus for controlling external signals output to a telephone line by a signal generator in a telecommunications device having an on/off hook detector, in response to internal signals produced by a user of an input unit in the telecommunications device, said apparatus comprising:

a detection unit, operatively connected to the telephone line, to detect at least one of status of the telecommunications device and received signals from the telephone line and to generate a detection signal upon detecting passage of a predetermined period of time since any of the internal signals were generated; and

a control unit, operatively connected to said detection unit and the signal generator, to control selection between pulse code and dual tone multifrequency signals for production as the external signals corresponding to the internal signals, including instructing the signal generator to output the dual tone multifrequency signals as the external signal corresponding to subsequent internal signals when the on/off hook detector indicates that the telecommunications device is in an off-hook state and the detection signal has been generated.

2. An apparatus for controlling external signals output to a telephone line by a signal generator in a telecommunications device having an on/off hook detector, in response to internal signals produced by a user of an input unit in the telecommunications device, said apparatus comprising:

a detection unit, operatively connected to the telephone line, to detect at least one of status of the telecommunications device and received signals from the telephone line and to output a detection signal upon detection of at least one of a ringback signal, a voice frequency signal, a dual tone multifrequency signal and data stream signals, from the telephone line; and

a control unit, operatively connected to said detection unit and the signal generator, to control selection between pulse code and dual tone multifrequency signals for production as the external signals corresponding to the internal signals, including instructing the signal generator to output dual tone multifrequency signals as the external signals corresponding to subsequent internal signals when the detection unit generates the detection signal after the on/off hook detector indicates that the telecommunications device is in an off-hook state and internal signals have been generated.

3. An apparatus as recited in claim 2, wherein the detection unit detects receipt of the ringback signal from the telephone line.

4. An apparatus as recited in claim 2, wherein said detection unit detects voice frequency signals from the telephone line.

5. An apparatus as recited in claim 4, wherein said detection unit determines existence of the voice frequency signals when there is a predetermined decibel gain in volume of signals received from the telephone line.

6. An apparatus as recited in claim 2, wherein said detection unit detects dual tone multifrequency signals from another unit connected via the telephone line.

7. An apparatus as recited in claim 2, wherein said detection unit detects a data stream received from the telephone line.

8. A telecommunications device for communications over a telephone line, comprising:

an input device, including a keypad, to generate internal signals other than voice signals indicative of input by a user;

a signal generator, operatively connected to said input device, to output over the telephone line one of pulse code and dual tone multifrequency signals as external signals corresponding to the internal signals; and

a control unit, operatively connected to said signal generator, to control selection between the pulse code and dual tone multifrequency signals for generation as the external signals, in dependence upon at least one of status of the telecommunications device and received signals from the telephone line, including

an on/off hook detector, operatively connected to said automatic switch unit, to generate an off-hook signal when said telecommunications device is in an off-hook state;

an automatic switch unit, operatively connected to the signal generator, to control selection between the pulse code and dual tone multifrequency signals for production as the external signals corresponding to the internal signals; and

a detection unit, operatively connectable to the telephone line and said automatic switch unit, to detect the at least one of the status of the telecommunication device and the received signals from the telephone line and to generate the detection signal after the initial internal signals are generated by said keypad and a predetermined period of time passes without any further internal signals being generated in the off-hook state.

9. A telecommunications device for communications over a telephone line, comprising:

an input device, including a keypad, to generate internal signals other than voice signals indicative of input by a user;

a signal generator, operatively connected to said input device, to output over the telephone line one of pulse code and dual tone multifrequency signals as external signals corresponding to the internal signals; and

a control unit, operatively connected to said signal generator, to control selection between the pulse code and dual tone multifrequency signals for generation as the external signals, in dependence upon at least one of status of the telecommunications device and received signals from the telephone line, including

a detection unit, operatively connectable to the telephone line, to detect the at least one of the status of the telecommunications device and the received signals from the telephone line and to output a detection signal upon detection of one of a ringback signal, a voice frequency signal, a dual tone multifrequency signal and data stream signals;

an automatic switch unit, operatively connected to said detection unit and the signal generator, to control selection between the pulse code and dual tone multifrequency signals for production as the external signals corresponding to the internal signals;

an on/off hook detector, operatively connected to said automatic switch unit, to generate an off-hook signal when said telecommunications device is in an off-hook state; and

means for instructing said signal generator to output the dual tone multifrequency signals as the external signals corresponding to subsequent internal signals when the detection signal is generated after the off-hook signal and after initial internal signals are generated by said keypad.

10. A telecommunications device for communications over a telephone line, comprising:

an input device, including a keypad, to generate internal signals other than voice signals indicative of input by a user;

a signal generator operatively connected to said input device, to output over the telephone line one of pulse code and dual tone multifrequency signals as external signals corresponding to the internal signals;

a control unit, operatively connected to said signal generator, to control selection between the pulse code and dual tone multifrequency signals for generation as the external signals, in dependence upon at least one of status of the telecommunications device and received signals from the telephone line, including

a detection unit, operatively connectable to the telephone line, to detect the at least one of the status of the telecommunications device and the received signals from the telephone line;

an automatic switch unit, operatively connected to said detection unit and the signal generator, to control selection between the pulse code and dual tone multifrequency signals for production as the external signals corresponding to the internal signals; and

an on/off hook detector, operatively connected to said automatic switch unit, to detect when the telecommunications device is in an off-hook state and to send an off-hook signal to said automatic switch unit upon detecting the off-hook state; and

a manual switch, operatively connected to said automatic switch unit, having at least first and second positions selectable by the user to indicate generation of the pulse code signals and the dual tone multifrequency signals, respectively, as the external signals corresponding to initial internal signals produced immediately following the off-hook signal, said automatic switch unit instructing said signal generator to output only dual tone multifrequency signals when said manual switch is in the second position and instructs said signal generator to switch from generation of the pulse code signals to the dual tone multifrequency signals upon generation of the detection signal when said manual switch is in the first position.

11. A method of automatically outputting to a telephone line dual tone multifrequency signals generated by a telecommunications device manually switchable between generating pulse code and dual tone multifrequency signals, said method comprising the steps of:

(a) detecting an off-hook state in the telecommunications device;

(b) detecting non-voice input by a user of the telecommunications device to produce initial external signals output to the telephone line;

(c) detecting at least one of a ring-back signal from the telephone line, voice frequency signals from the telephone line, tone signals from the telephone line, data stream signals from the telephone line and a predetermined period of time without generation of the external signals, after said detecting in step (a) is followed by said detecting in step (b); and

(d) automatically producing dual tone multifrequency signals after said detecting in step (c) regardless of whether the pulse code signals or the dual tone multifrequency signals are generated prior to said detecting in step (c).