Method for selectively controlling the propagation of dual-tone multi-frequency signals within a telecommunications network

• US 5,327,492 A
• Filed: 04/30/1992
• Issued: 07/05/1994
• Est. Priority Date: 04/30/1992
• Status: Expired due to Term

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Original Assignee: AT&T, Inc.
• Inventors: Parola, Dario L.
• Primary Examiner(s): Dwyer, James L.
• Assistant Examiner(s): SAINT SURIN, JACQUES M
• Application Number:
  US07/876,555
• Time in Patent Office: 796 Days
• Field of Search: 379/283, 379/361, 379/354, 379/386, 379/351, 379/199, 379/95, 370/110.1
• US Class Current: 379/361
• CPC Class Codes: H04Q 3/42 Circuit arrangements for indirect selecting controlled by common circuits, e.g. register controller, marker

Abstract

A method for monitoring a network communications channel to detect specific DTMF triggers transmitted by a network user during either a pre-answer or a post-answer period of a call supported by the channel, and, in response to the detected DTMF triggers, controllably prohibiting the propagation of subsequent DTMF signals transmitted over the channel by the network user. Specifically, possible disruption of a communication between the network user and other parties caused by transmission of DTMF signals is eliminated by advantageously transmitting the DTMF triggers during the pre-answer period of a call. Furthermore, another deficiency of prior network-based arrangements for restricting the propagation of DTMF signals is overcome, as the invention may be practiced without the introduction of any significant propagation delay to a network.

Claims

1. A method for selectively controlling the propagation of dual-tone multi-frequency signals along a communications channel within a telecommunication network, comprising the steps of:

monitoring the communications channel to detect, during a pre-answer period of a call initiated from a first network user to a second network user supported by the communications channel, one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user; and

prohibiting, in response to detection of a specific one or more dual-tone multi-frequency signals, all dual-tone multi-frequency signals subsequently transmitted along said communications channel by said first network user from being propagated to said second network user, while permitting the propagation of all other voice channel audio signals subsequently transmitted along said communication channel from said first network user to said second network user.

2. A method for selectively controlling the propagation of dual-tone multi-frequency signals along a communications channel within a telecommunication network, comprising the steps of:

monitoring the communications channel to detect, during a pre-answer period of a call initiated from a first network user to a second network user supported by the communications channel, one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user;

prohibiting, in response to detection of a specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user, all dual-tone multi-frequency signals subsequently transmitted along said channel by said first network user from being propagated to said second network user;

monitoring the communications channel to detect, after a call supported by the communications channel is completed between said first network user to said second network user, one or more dual-tone multi-frequency signals transmitted along said communications channel by said second network user; and

prohibiting, in response to detection of a specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said second network user, all dual-tone multi-frequency signals subsequently transmitted along said channel by said second network user from being propagated to said first network user.

3. A method for selectively controlling the propagation of dual-tone multi-frequency signals along a communications channel within a telecommunication network, comprising the steps of:

monitoring the communications channel to detect, during a pre-answer period of a call initiated from a first network user to a second network user supported by the communications channel, one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user;

prohibiting, in response to detection of a first specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user, all dual-tone multi-frequency signals subsequently transmitted along said channel by said first network user from being propagated to said second network user;

monitoring the communications channel to detect, after a call supported by the communications channel is completed between said first network user to said second network user, one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user, and

allowing, in response to detection of a second specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user, all dual-tone multi-frequency signals subsequently transmitted along said channel by said first network user to propagate to said second network user.

4. The invention of claim 3 further characterized by prohibiting the propagation of all dual-tone multi-frequency signals transmitted along said channel by said first network user to said second network user, in response to the detection of the transmission of said first specific one or more dual-tone multi-frequency signal by said first network user after said call connection between said first network user and said second network user has been established.

5. The invention of claim 3 further characterized by prohibiting the propagation of all dual-tone multi-frequency signals transmitted along said channel by said second network user to said first network user, in response to the detection of the transmission of said first specific one or more dual-tone multi-frequency signal by said second network user after said call connection between said first network user and said second network user has been established.

6. The invention of claim 5 further characterized by allowing the propagation of all dual-tone multi-frequency signals transmitted along said channel by said second network user to said first network user, in response to the detection of the transmission of said second specific one or more dual-tone multi-frequency signal by said second network user after said call connection between said first network user and said second network user has been established.

7. A method for selectively controlling the propagation of dual-tone multi-frequency signals along a communications channel within a telecommunication network, comprising the steps of:

receiving, via said telecommunication network, during a pre-answer period of a call initiated from a first network user to a second network user supported by the communications channel, an identifying signal associated with said first network user; and

prohibiting, in response to said received identifying signal, all dual-tone multi-frequency signals subsequently transmitted along said communications channel by said first network user from being propagated to said second network user, while permitting the propagation of all other voice channel audio signals subsequently transmitted along said communication channel from said first network user to said second network user.

8. The invention of claim 7 further characterized by:

monitoring the communications channel to detect, after a call supported by the communications channel is completed between said first network user to said second network user, one or more dual- tone multi-frequency signals transmitted along said communications channel by said first network user;

allowing, in response to said detection of a first specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user, all dual-tone multi-frequency signals subsequently transmitted along said channel by said first network user to propagate to said second network user; and

prohibiting, in response to said detection of a second specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user, all dual- tone multi-frequency signals subsequently transmitted along said channel by said first network user from being propagated to said second network user.

9. A method for selectively controlling the propagation of dual-tone multi-frequency signals along a communications channel within a telecommunication network, comprising the steps of:

receiving, via said telecommunication network, during a pre-answer period of a call initiated from a first network user to a second network user supported by the communications channel, an identifying signal associated with said second network user; and

prohibiting, in response to said received identifying signal, all dual-tone multi-frequency signals subsequently transmitted along said communications channel by said second network user from being propagated to said first network user, while permitting the propagation of all other voice channel audio signals subsequently transmitted along said communication channel from said second network user to said first network user.

10. The invention of claim 9 further characterized by:

monitoring the communications channel to detect, after a call supported by the communications channel is completed between said first network user to said second network user, one or more dual- tone multi-frequency signals transmitted along said communications channel by said second network user;

allowing, in response to said detection of a first specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said second network user, all dual-tone multi-frequency signals subsequently transmitted along said channel by said second network user to propagate to said first network user; and

prohibiting, in response to said detection of a second specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said second network user, all dual-tone multi-frequency signals subsequently transmitted along said channel by said second network user from being propagated to said first network user.

11. A method for selectively controlling the propagation of dual-tone multi-frequency signals along a communications channel within a telecommunication network, comprising the steps of:

receiving, via said telecommunication network, during a pre-answer period of a call initiated from a first network user to a second network user supported by the communications channel, an identifying signal associated with said first network user;

receiving, via said telecommunication network, during a pre-answer period of a call initiated from a first network user to a second network user supported by the communications channel, an identifying signal associated with said second network user; and

prohibiting all dual-tone multi-frequency signals subsequently transmitted along said communications channel by said first network user from being propagated to said second network user as a function of both received identifying signals, while permitting the propagation of all other voice channel audio signals subsequently transmitted along said communication channel from said first network user to said second network user.

12. The invention of claim 11 further characterized by:

monitoring the communications channel to detect, after a call supported by the communications channel is completed between said first network user to said second network user, one or more dual- tone multi-frequency signals transmitted along said communications channel by said first network user;

allowing, in response to said detection of a first specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user, all dual-tone multi-frequency signals subsequently transmitted along said channel by said first network user to propagate to said second network user; and

prohibiting, in response to said detection of a second specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said first network user, all dual- tone multi-frequency signals subsequently transmitted along said channel by said first network user from being propagated to said second network user.

13. A method for selectively controlling the propagation of dual-tone multi-frequency signals along a communications channel within a telecommunication network, comprising the steps of:

receiving, via said telecommunication network, during a pre-answer period of a call initiated from a first network user to a second network user supported by the communications channel, an identifying signal associated with said first network user;

receiving, via said telecommunication network, during a pre-answer period of a call initiated from a first network user to a second network user supported by the communications channel, an identifying signal associated with said second network user; and

prohibiting all dual-tone multi-frequency signals subsequently transmitted along said communications channel by said second network user from being propagated to said first network user as a function of both received identifying signals, while permitting the propagation of all other voice channel audio signals subsequently transmitted along said communication channel from said second network user to said first network user.

14. The invention of claim 13 further characterized by:

monitoring the communications channel to detect, after a call supported by the communications channel is completed between said first network user to said second network user, one or more dual- tone multi-frequency signals transmitted along said communications channel by said second network user;

allowing, in response to said detection of a first specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said second network user, all dual-tone multi-frequency signals subsequently transmitted along said channel by said second network user to propagate to said first network user; and

prohibiting, in response to said detection of a second specific one or more dual-tone multi-frequency signals transmitted along said communications channel by said second network user, all dual-tone multi-frequency signals subsequently transmitted along said channel by said second network user from being propagated to said first network user.