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Starting with Active Call Center version 2.6.0, a broad variety of PCM wave file audio formats are supported. In order to maximize performance, the user should select the audio format best suited for their particular hardware.
Active Call Center audio formats are always PCM mono with variable sampling and bit rates. Generally speaking, the following formats should be used:
For best performance, these formats should apply to all audio that is played back and recorded. Users should be aware that most telephone lines cannot carry audio at better than a 11025 Hz sampling rate, so using higher sampling rates will not improve audio quality.
For audio playback, this means that all wave files should have the given format and the text-to-speech engine should be set to deliver audio in the same format. Active Call Center versions that include the Lucent text-to-speech engine will include speakers that support both audio formats: speakers whose names end in "-T" or "-TE" are 8000 Hz 16 bit speakers and speakers whose names end in "-TD" or "-TED" are 11025 Hz 8 bit speakers. The Microsoft Text-to-Speech Engines marked "(for Telephone)" will deliver 8000 Hz audio. Other speakers will deliver different audio types, test them to find which works best on your hardware.
If you use an audio playback format not supported by your hardware, Active Call Center will attempt to convert and play the audio anyway. If the conversion fails, the call will be disconnected abruptly.
For audio recording, Active Call Center defaults to recording 8000 Hz 16 bit audio. An included option allows the user to switch the recording format to 11025 Hz 8 bit, the optimal Dialogic format supported by Active Call Center. To switch the audio recording format, check the correct option under Tools... Voice Telephony Settings.