1.4. Play and Record Features

• 1.4.1. Change Length Of Built-In Beep Tone
• 1.4.2. Speed and Volume Control
• 1.4.3. Transaction Record
• 1.4.4. Offset Playback of WAVE Files
• 1.4.5. Silence Compressed Record (SCR)
• 1.4.6. Echo Cancellation Resource (ECR)
• 1.4.7. GSM and G.726 Voice Coders

1.4.1. Change Length Of Built-In Beep Tone

The dx_settonelen( ) function can be used to modify the duration of the built-in beep tone that some application programs use to indicate the start of a recording (sometimes referred to as the pre-record beep) or a playback.

1.4.2. Speed and Volume Control

The voice software speed and volume support contains functions and data structures to control the speed and volume of play on a channel. For example, an end user may control the speed or volume of a message by entering a previously established DTMF tone.

NOTE:

Speed can be controlled on playbacks using 24 kbps or 32 kbps ADPCM only. Volume can be controlled on all playbacks regardless of the encoding algorithm.

Speed and Volume control are available on D/21D, D/21E, D/41D, D/41E, D/41ESC, D/81A, D/121B, D/160SC-LS, D/240SC, D/240SC-T1, D/300SC-E1 and D/320SC boards only. Do not use the Speed and Volume control functions to control speed on the D/120, D/121 or D/121A boards.

1.4.3. Transaction Record

Transaction Record enables the recording of a two-party conversation by allowing two SCbus time slots from a single channel to be recorded. This feature is useful for Call Center applications where it is necessary to archive a verbal transaction or record a live conversation. A live conversation requires two timeslots on the SCbus. Dialogic voice boards today can only record one timeslot at a time. No loss of channel density is realized. A D/160SC-LS can still record 16 simultaneous conversations. Voice activity on two channels can be summed and stored in a single file, device and/or memory.

The transaction record feature is compatible with the following Dialogic hardware: D/80SC, D/160SC, D/240SC, D/320SC, D/160SC-LS, D/240SC-T1, D/300SC-E1, D/240SC-2T1, D/300SC2E1, D/480SC-2T1, D/600SC-2E1.

The function dx_mreciottdata( ) was added to the Dialogic Voice Library to implement the transaction record feature. It is an extension of the dx_reciottdata( ) function.

1.4.4. Offset Playback of WAVE Files

The dx_playiottdata( ) function can now be used to play WAVE files using offsets specified in the DX_IOTT data structure.

1.4.5. Silence Compressed Record (SCR)

SCR enables recording of a caller's message with silent pauses eliminated. This results in smaller size voice files with no loss of intelligibility. Parameters in the voice.prm file are used to control this feature.

1.4.6. Echo Cancellation Resource (ECR)

The Echo Cancellation Resource (ECR) feature is a voice channel mode that reduces the echo component on an external SCbus time slot signal. ECR provides the following features to an application:

• Adds the ability to utilize the echo cancellation function on signals external to the voice channels
• Enables the use of the voice channel to perform echo cancellation on non-voice channel signals
• Improves voice quality during full-duplex conversations
• Provides the ability to modify the size of the voice board firmware buffers to reduce latency for Internet telephony applications
• Provides the option to modify the characteristics of the echo canceller, such as enabling or disabling non-linear processing (NLP) during echo cancellation

1.4.7. GSM and G.726 Voice Coders

The voice software supports the GSM and G.726 voice coders through the I/O functions that use a DX_XPB data structure. For more detailed information, refer to the DX_XPB Data Structure in the Voice Programmer's Guide.

• WAVE GSM 6.10 full-rate voice coder
• G.726 bit-exact voice coder

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