User's Manual
Table Of Contents
- Contents
- Figures
- Tables
- Revision History
- About This Publication
- 1. Product Description
- 2. Programming Models
- 3. Device Handling
- 4. Event Handling
- 5. Error Handling
- 6. Application Development Guidelines
- 7. Call Progress Analysis
- 7.1 Call Progress Analysis Overview
- 7.2 Call Progress and Call Analysis Terminology
- 7.3 Call Progress Analysis Components
- 7.4 Using Call Progress Analysis on DM3 Boards
- 7.5 Call Progress Analysis Tone Detection on DM3 Boards
- 7.6 Media Tone Detection on DM3 Boards
- 7.7 Default Call Progress Analysis Tone Definitions on DM3 Boards
- 7.8 Modifying Default Call Progress Analysis Tone Definitions on DM3 Boards
- 7.9 Call Progress Analysis Errors
- 7.10 Using Call Progress Analysis on Springware Boards
- 7.11 Call Progress Analysis Tone Detection on Springware Boards
- 7.12 Media Tone Detection on Springware Boards
- 7.13 Default Call Progress Analysis Tone Definitions on Springware Boards
- 7.14 Modifying Default Call Progress Analysis Tone Definitions on Springware Boards
- 7.15 SIT Frequency Detection (Springware Only)
- 7.15.1 Tri-Tone SIT Sequences
- 7.15.2 Setting Tri-Tone SIT Frequency Detection Parameters
- 7.15.3 Obtaining Tri-Tone SIT Frequency Information
- 7.15.4 Global Tone Detection Tone Memory Usage
- 7.15.5 Frequency Detection Errors
- 7.15.6 Setting Single Tone Frequency Detection Parameters
- 7.15.7 Obtaining Single Tone Frequency Information
- 7.16 Cadence Detection in Basic Call Progress Analysis (Springware Only)
- 8. Recording and Playback
- 8.1 Overview of Recording and Playback
- 8.2 Digital Recording and Playback
- 8.3 Play and Record Functions
- 8.4 Play and Record Convenience Functions
- 8.5 Voice Encoding Methods
- 8.6 G.726 Voice Coder
- 8.7 Transaction Record
- 8.8 Silence Compressed Record
- 8.9 Recording with the Voice Activity Detector
- 8.10 Streaming to Board
- 8.11 Pause and Resume Play
- 8.12 Echo Cancellation Resource
- 9. Speed and Volume Control
- 10. Send and Receive FSK Data
- 11. Caller ID
- 12. Cached Prompt Management
- 13. Global Tone Detection and Generation, and Cadenced Tone Generation
- 13.1 Global Tone Detection (GTD)
- 13.1.1 Overview of Global Tone Detection
- 13.1.2 Global Tone Detection on DM3 Boards versus Springware Boards
- 13.1.3 Defining Global Tone Detection Tones
- 13.1.4 Building Tone Templates
- 13.1.5 Working with Tone Templates
- 13.1.6 Retrieving Tone Events
- 13.1.7 Setting GTD Tones as Termination Conditions
- 13.1.8 Maximum Amount of Memory for Tone Templates
- 13.1.9 Estimating Memory
- 13.1.10 Guidelines for Creating User-Defined Tones
- 13.1.11 Global Tone Detection Application
- 13.2 Global Tone Generation (GTG)
- 13.3 Cadenced Tone Generation
- 13.3.1 Using Cadenced Tone Generation
- 13.3.2 How To Generate a Custom Cadenced Tone
- 13.3.3 How To Generate a Non-Cadenced Tone
- 13.3.4 TN_GENCAD Data Structure - Cadenced Tone Generation
- 13.3.5 How To Generate a Standard PBX Call Progress Signal
- 13.3.6 Predefined Set of Standard PBX Call Progress Signals
- 13.3.7 Important Considerations for Using Predefined Call Progress Signals
- 13.1 Global Tone Detection (GTD)
- 14. Global Dial Pulse Detection
- 14.1 Key Features
- 14.2 Global DPD Parameters
- 14.3 Enabling Global DPD
- 14.4 Global DPD Programming Considerations
- 14.5 Retrieving Digits from the Digit Buffer
- 14.6 Retrieving Digits as Events
- 14.7 Dial Pulse Detection Digit Type Reporting
- 14.8 Defines for Digit Type Reporting
- 14.9 Global DPD Programming Procedure
- 14.10 Global DPD Example Code
- 15. R2/MF Signaling
- 16. Syntellect License Automated Attendant
- 17. Building Applications
- Glossary
- Index
104 Voice API Programming Guide — June 2005
Recording and Playback
8.12.3 Modes of Operation
The echo cancellation resource feature has two modes of operation as discussed in the following
topics:
• Overview of Modes
• Standard Voice Processing (SVP) Mode
• Echo Cancellation Resource (ECR) Mode
8.12.3.1 Overview of Modes
When the ECR feature is enabled at initialization time on a supported board, there are two possible
modes of operation: SVP and ECR. Until ECR mode is activated, the board operates in the
Standard Voice Processing (SVP) mode, which offers default echo cancellation. The ECR mode,
which provides high-performance echo cancellation, can be dynamically activated or deactivated
on any voice channel of the enabled board.
To enable ECR mode, set EC_Resource to ON in the .cfg file or in the configuration manager
(DCM) (Windows only) when configuring the board.
8.12.3.2 Standard Voice Processing (SVP) Mode
All voice channels are initially in the SVP mode with the default echo cancellation for ECR
feature-enabled boards. The SVP mode utilizes a 48 tap (6 ms) echo canceller. In SVP mode, all
voice functions operate as usual, with one exception. If a channel in SVP mode is playing a file and
listening (via a dx_listen( ) function), then playback transmits data on both the standard voice-
transmit time slot and the echo-cancellation transmit time slot. The standard voice-transmit time
slot carries the play signal. The echo cancellation time slot carries an echo-canceled version of the
signal from the receive time slot. This echo-canceled signal is derived from the original play signal
(the echo reference) and the signal from the receive time slot specified in the dx_listen( ) function
(the echo carrying signal).
8.12.3.3 Echo Cancellation Resource (ECR) Mode
Any voice channel can be placed into ECR mode via the dx_listenecr( ) or dx_listenecrex( )
function on an ECR feature-enabled board. When a voice channel is placed in ECR mode, the echo
reference TDM bus time slot is specified and the high performance echo canceller is activated. The
ECR mode supplies 128 tap (16 ms) echo cancellation.
When an echo carrying signal is provided as an input to the ECR by an associated dx_listen( )
function, an echo-canceled version of that signal is produced on the echo-cancellation TDM bus
time slot. If no echo carrying signal is defined, the contents of the echo-cancellation transmit time
slot are undefined and unpredictable. Other characteristics of the echo canceller can be set if the