Method and apparatus for normalizing DTMF messages from a cellular mobile station

• US 6,151,514 A
• Filed: 04/22/1998
• Issued: 11/21/2000
• Est. Priority Date: 04/22/1998
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Nortel Networks Corporation
• Inventors: Chen, Mark, Cheng, Heikwan
• Primary Examiner(s): Trost, William G.
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US09/064,530
• Time in Patent Office: 944 Days
• Field of Search: 455/550, 455/564, 455/565, 455/556, 455/557, 455/575, 455/406-409, 455/412, 455/418, 455/419, 455/403, 379/361, 379/386, 379/283, 379/418, 379/93.05, 379/165, 379/347, 370/345, 370/466, 370/473
• US Class Current: 455/564
• CPC Class Codes: H04M 1/27485 Appending a prefix to or inserting a pause into a dialling sequence
• CPC Class Codes: H04M 1/724 User interfaces specially adapted for cordless or mobile telephones
• CPC Class Codes: H04M 3/24 with provision for checking the normal operation
• CPC Class Codes: H04Q 1/45 using multi-frequency signalling H04Q1/46 takes precedence

Abstract

A system for normalizing a Dual-Tone Multi-Frequency ("DTMF") tone is provided for use in a digital wireless telecommunications system. The normalization system has an electronic memory with normalization parameter variable that stores a redefinable value. A programmable DTMF tone generator circuit is coupled to the electronic memory. The tone generator circuit has an input terminal for receiving a DTMF message packet. A program, executable on the DTMF tone generator, normalizes the DTMF message packet by substituting the redefinable value of the parameter variable in the DTMF message packet such that a normalized DTMF tone is transmitted through an output terminal of the DTMF tone generator circuit.

Claims

1. A system for normalizing a Dual-Tone Multi-Frequency ("DTMF") tone used in a digital wireless telecommunications system having a plurality of DTMF requirements comprising:

an electronic memory having at least a first and a second parameter variable, each of said first and said second parameter variables storing a redefinable value; and

a programmable DTMF tone generator circuit, said DTMF tone generator circuit coupled to said electronic memory and having an input terminal for receiving a DTMF message packet and an output terminal for transmitting a DTMF tone corresponding to the DTMF message packet; and

a program executable on said DTMF tone generator, said program normalizing said DTMF message packet to conform the message packet to the DTMF requirements of the telecommunications system by substituting said redefinable value of each of said first and said second parameter variable in said DTMF message packet such that a normalized DTMF tone corresponding to the DTMF message packet is transmitted through said output terminal.

2. The system of claim 1 wherein said first parameter variable is an off-length duration for a DTMF tone.

3. The system of claim 1 wherein said second parameter variable is an on-length duration for a DTMF tone.

4. The system of claim 1 further comprising:

a wireless telecommunications switch coupled to said output terminal of said DTMF tone generator circuit; and

a subscriber service coupled to said telecommunications switch such that said subscriber service can receive said normalized DTMF tone from said DTMF tone generator circuit.

5. The system of claim 1 further comprising:

a user interface coupled to said DTMF tone generator circuit, said user interface for accepting from a user said redefinable value for each of said first and said second parameter variables and for storing said redefinable value in said electronic memory.

6. The system of claim 5 wherein said user interface comprises:

a Base Station Manager ("BSM"); and

a graphic user interface program executable on said BSM.

7. The system of claim 6 wherein said BSM is a computer workstation.

8. The system of claim 1 wherein said DTMF message packet comprises a header field, a duration field, and a digit field.

9. The system of claim 1 wherein said DTMF tone generator circuit is a digital signal processor.

10. The system of claim 1 wherein said DTMF tone generator circuit is a DTMF transceiver coupled to a microprocessor.

11. A microprocessor-executable method for providing a normalized DTMF signal on a digital wireless telecommunications system having a plurality of DTMF requirements, the method comprising the steps of:

receiving a Dual Tone Multi-Frequency ("DTMF") message packet from a mobile station;

retrieving from at least a first and a second parameter variable a redefinable value;

substituting corresponding parameters in the DTMF message packet with the redefinable value stored in the first and the second parameter variable to conform the message packet to the DTMF requirements of the telecommunications system; and

transmitting a DTMF tone corresponding to the DTMF message packet, said packet having the at least a first and a second parameter variable.

12. The method for providing a configurable DTMF signal of claim 11 further comprising the step of:

providing the redefinable value through a user interface.

13. The method of claim 11 wherein the DTMF message packet comprises a header field, a duration field, and a digit field.

14. The system of claim 11 wherein the first parameter variable is an off-length duration for a DTMF tone.

15. The system of claim 11 wherein the second parameter variable is an on-length duration for a DTMF tone.

16. An apparatus for providing a normalized DTMF signal on a digital wireless telecommunications system having a plurality of DTMF requirements comprising:

means for receiving a Dual Tone Multi-Frequency ("DTMF") message packet from a mobile station;

means for retrieving from at least a first and a second parameter variable a redefinable value;

means for substituting corresponding parameters in the DTMF message packet with the redefinable value stored in the first and the second parameter variable to conform the message packet to the DTMF requirements of the telecommunications system; and

means for transmitting a DTMF tone corresponding to the DTMF message packet, said packet having the at least a first and a second parameter variable.

17. The apparatus of claim 16 further comprising:

means for providing the redefinable value through a user interface.