By default, the Assistant uses the u-law audio format, the standard telephony format in North America, to play all of its audio
If desired, it can be configured to use A-law, the standard format in most of the world.
The [Settings] section of the LV_Platform.ini (located in the Assistant installation directory) contains four parameters, all of which can be set to ULAW or ALAW, that control what sort of audio will be used.
HARDWARE_AUDIO_FORMAT
Specifies the audio format that will be used, for both incoming and outgoing audio. This needs to be set to the same value that your Dialogic hardware is set to (see below).
VOX_AUDIO_FORMAT
Specifies the format that your prompts are recorded in. This can be different from the HARDWARE_AUDIO_FORMAT as the Assistant will convert them into the format specified by HARDWARE_AUDIO_FORMAT before they are played out to callers. By default, this is set to ULAW; you only need to change it if you have recorded your own prompts for the Assistant.
TTS_AUDIO_FORMAT
Specifies the audio format your text-to-speech engine will use. This can be different from the HARDWARE_AUDIO_FORMAT as the Assistant will convert audio into the format specified by HARDWARE_AUDIO_FORMAT before playing it out to callers.
Your Dialogic cards need to be set up to use the same format as specified by HARDWARE_AUDIO_FORMAT. To check this, open the Dialogic Configuration Manager, select the properties for a card, and click the Telephony Bus tab. Ensure that the PCMEncoding parameter is set to either ALAW or ULAW, depending on which you wish to use.