Acoustic Shock Protection

Acoustic Shock Protection (ASP) is a voice circuit-breaker feature that is designed to protect users, especially those wearing headsets, from exposure to loud, sustained, and piercing tones, such as those produced by a fax machine. It is a workplace-safety feature for voice calls. When the tone is present at the input of the ASP module, the audio path in the affected direction is muted to protect the listener, and a gentle alert tone is played out for as long as the tone persists. ASP may be inserted in either or both directions of a call, that is, applied to incoming packets to protect the ears of a listener on the Time-Division Multiplexing (TDM) gateway, applied to incoming PSTN calls (microphone signal) to protect the ears of listeners at the other end of the call, or applied to both simultaneously.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Restrictions for ASP

  • Supported on PVDM3 only.

  • Supported only on flex codec complexity.

  • No support for H.32x video call, complex forking calls, and fax and modem calls.

  • No support for TDM hairpin call.

  • The configuration under dial peer has higher priority than the configuration at the global level.

  • No support for conference calls, IP/SIP phones, and the Skinny Client Control Protocol (SCCP).

  • CLI supports enabling ASP but not disabling ASP.

  • No support for dynamically enabling or disabling ASP during a call.

Information About ASP

Acoustic Shock Protection

Acoustic Shock Protection (ASP) is an adaptive signal processing algorithm on the Digital Signal Processor (DSP) that analyzes incoming audio for the presence of offending tones that might harm humans. Offending tones include signals that are:

  • Loud

  • Tonal (energy concentrated around a single frequency)

  • Persistent (lasts longer than a few tens of milliseconds)

If an offending tone is present, the audio path in that direction is muted temporarily, and a quiet, alerting signal is played out to the listener side. The call is never dropped; only the audio is muted temporarily. If or when the tone disappears from the input, the mute is removed. ASP does not disrupt low-frequency tones (below 650 Hz) such as ringback, dial, and so forth. Since ASP is designed to mute only single-frequency tones, it allows multi-tone signals such as Dual Tone Multi-Frequency (DTMF) to pass unhindered. ASP is supported on TDM gateways (TDM-VoIP and TDM-TDM) and on the Cisco Unified Border Element (Cisco UBE).


Note

ASP is for voice calls only and not for faxes and modems.

Some of the best practices for ASP are as follows:

  • Use default values

  • Use ASP on dial peers where you are certain that people (not faxes) are listening.

  • Do not use ASP on dial peers associated with fax machines, modems, or TTY/TDD devices. Use fax-relay or modem-relay modes on dial peers dedicated to such devices.

  • ASP is designed for deployment in situations where customers have experienced acoustic shock safety issues. If there are issues like false triggering (for example, ASP alerts on regular voices), then you must turn off ASP. You can choose from three detector sensitivity modes: slow, auto, or fast. Fast mode is a highly sensitive hair-trigger. Auto mode is recommended. Slow mode lets more tone leak through, but has better rejection of false triggers.

How to Configure ASP

Creating the Media Profile for ASP

Perform this task to create a media profile to configure acoustic shock protection.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    media profile asp tag

    4.    mode mode

    5.    end


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.

     
    Step 2configure terminal


    Example:
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3media profile asp tag


    Example:
    Device(config)# media profile asp 5
     

    Creates the media profile to configure ASP and enters media profile configuration mode. The range for the media profile tag is from 1 to 10000.

     
    Step 4mode mode


    Example:
    Device(cfg-mediaprofile)# mode auto
     

    Sets the ASP sensitivity mode to preset = auto (which is default). Auto mode provides a good tradeoff between ASP speed and false trigger rejection.

    The other modes are:

    • slow—Presets ASP sensitivity mode to 1. This mode provides slower detection speed for reduced chance of false triggers.

    • fast—Presets ASP sensitivity mode to 2. This mode provides faster detection speed but higher chance of false triggers.

    • expert—This mode exposes direct control of individual ASP parameters and is recommended for test use only.

     
    Step 5end


    Example:
    Device(config)# end
     

    Returns to privileged EXEC mode.

     

    Creating the Media Profile to Enable ASP

    After the media profile is created, you must create a media class to enable acoustic shock protection. Perform this task to create a media class.

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    media class tag

      4.    asp profile tag

      5.    end


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Device> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.

       
      Step 2configure terminal


      Example:
      Device# configure terminal
       

      Enters global configuration mode.

       
      Step 3media class tag


      Example:
      Device(config)# media class 2
       

      Creates the media class to enable the acoustic shock protection feature and enters media class configuration mode. The range for the media class tag is from 1 to 10000.

       
      Step 4asp profile tag


      Example:
      Device(cfg-mediaclass)# asp profile 200
       

      Applies the media profile to the media class. The range for the media profile ASP tag is from 1 to 10000.

       
      Step 5end


      Example:
      Device(cfg-mediaclass)# end
       

      Returns to privileged EXEC mode.

       

      Configuring the Media Class at a Dial Peer Level for ASP

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    dial-peer voice tag pots

        4.    media-class tag

        5.    end


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 enable


        Example:
        Device> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.

         
        Step 2configure terminal


        Example:
        Device# configure terminal
         

        Enters global configuration mode.

         
        Step 3dial-peer voice tag pots


        Example:
        Device(config)# dial-peer voice 20 pots
         

        Defines a particular dial peer and enters dial-peer voice configuration mode. The range for the dial-peer voice tag is from 1 to 1073741823.

         
        Step 4media-class tag


        Example:
        Device(config-dial-peer)# media-class 2
         

        Applies the media class to the specific dial peer. The range for the media class tag number is from 1 to 10000.

         
        Step 5end


        Example:
        Device(config-dial-peer)# end
         

        Returns to privileged EXEC mode.

         

        Configuring the Media Class Globally for ASP

        SUMMARY STEPS

          1.    enable

          2.    configure terminal

          3.    media service

          4.    enhancement

          5.    tdm tag

          6.    end


        DETAILED STEPS
           Command or ActionPurpose
          Step 1 enable


          Example:
          Device> enable
           

          Enables privileged EXEC mode.

          • Enter your password if prompted.

           
          Step 2configure terminal


          Example:
          Device# configure terminal
           

          Enters global configuration mode.

           
          Step 3media service


          Example:
          Device(config)# media service
           

          Enters media service configuration mode.

           
          Step 4enhancement


          Example:
          Device(cfg-mediaservice)# enhancement
           

          Enters the submode enhance of media service.

           
          Step 5tdm tag


          Example:
          Device(cfg-service-enhance)# tdm 2
           

          Applies the TDM call globally. The range for the media class tag number is from 1 to 10000.

           
          Step 6end


          Example:
          Device(config-dial-peer)# end
           

          Returns to privileged EXEC mode.

           

          Verifying ASP

          Perform this task to verify the voice quality metrics.

          SUMMARY STEPS

            1.    enable

            2.    show call active voice stats | b pid:


          DETAILED STEPS
            Step 1   enable


            Example:
            Device> enable

            Enables privileged EXEC mode.

            Step 2   show call active voice stats | b pid:


            Example:
            Device# show call active voice stats | b pid:1300

11EC : 5 09:14:25.971 PDT Thu Jul 28 2011.1 +1130 pid:1300 Answer 1300 active dur 00:01:36 tx:17/321 rx:17/321 dscp:0 media:0
DSP/TX: PK=17, SG=0, NS=1, DU=90570, VO=320
DSP/RX: PK=17, SG=0, CF=1, RX=90570, VO=320, BS=0, BP=0, LP=0, EP=0
….
DSP/DL: RT=0, ED=0
MIC Direction:
DSP/NR: NR=1, ND=0, LV=257, IN=1, PN=0, ON=0
DSP/AS: AE=1, AD=0, AV=0, AM=0, NT=0, DT=0, TT=0, TD=0, LF=0, LD=0
EAR Direction:
DSP/NR: NR=0, ND=0, LV=0, IN=0, PN=0, ON=0
DSP/AS: AE=0, AD=0, AV=0, AM=0, NT=0, DT=0, TT=0, TD=0, LF=0, LD=0
11EC : 6 09:14:25.973 PDT Thu Jul 28 2011.2 +1130 pid:2300 Originate 2300 active dur 00:01:36 tx:17/457 rx:17/321 dscp:0 media:0
Telephony call-legs: 1
SIP call-legs: 0
H323 call-legs: 1

            Displays information about digital signal processing (DSP) voice quality metrics.

            Troubleshooting Tips

            The following commands can help troubleshoot ASP:

            • debug voip hpi all

            • debug voip dsmp all

            • debug voip dsm all

            • debug voip vtsp all

            • debug vpm dsp all

            Configuration Examples for the Acoustic Shock Protection Feature

            Example: Enabling ASP Globally 

            media profile asp 6 
! 
media class 1
  asp profile 6
!
media service
  enhancement 
    tdm 1

            Example: Enabling ASP on a Dial Peer 

            media profile asp 4  
! 
media class 1
  asp profile 4
! 
dial-peer voice 2100 pots
  destination-pattern 2100 
  incoming called-number 1100 
  media-class 1 
  port 0/2/0:1
  forward-digits all
 dial-peer voice 1300 voip 
 destination-pattern 1300 session target ipv4:1.2.146.102 media-class 1

            Feature Information for Acoustic Shock Protection

            The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

            Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

            Table 1 Feature Information for Acoustic Shock Protection

            Feature Name

            Releases

            Feature Information

            Acoustic Shock Protection

            15.2(2)T, 15.2(3)T

            Acoustic Shock Protection (ASP) is a voice circuit-breaker feature that is designed to protect users, especially those wearing headsets, from exposure to loud, sustained, and piercing tones, such as those produced by a fax machine. It is a workplace-safety feature for voice calls. ASP is supported on TDM gateways and on Cisco UBE.

            The following commands were introduced or modified: media profile asp, media service.

            Acoustic Shock Protection

            Cisco IOS XE Release 3.6S

            Acoustic Shock Protection (ASP) is a voice circuit-breaker feature that is designed to protect users, especially those wearing headsets, from exposure to loud, sustained, and piercing tones, such as those produced by a fax machine. It is a workplace-safety feature for voice calls. ASP is supported on TDM gateways and on Cisco UBE.

            In Cisco IOS XE Release 3.6S, this feature was implemented on the Cisco Unified Border Element (Enterprise)

            The following commands were introduced or modified: media profile asp, media service.