[Asterisk-Users] Correction: Asterisk sound files, audio bandwidth, and sound quality

[Kevin P. Fleming]

Stephen Bosch wrote:

> 1. Can I *record* audio from a TDM-400 channel at a sample rate above
> 8 kHz? Can I record at 16 bits? (This is most important.)

No TDM hardware supports sample rates above 8KHz, since that is what the 
PSTN is designed for. Zaptel hardware can possibly be convinced to 
supply 16-bit signed linear audio, but I don't know of anyone who has 
tried it. Normally the hardware provides the audio stream already 
compressed to 8-bit ulaw or alaw.

> 2. Can I use a prompt with a sample rate above 8 kHz? Will the
> TDM-400 card support it? How can I do this?

See above: no.

> What is the 16 bit signed Linear PCM format? How do I get Asterisk (1.2)
> to use such a sound file instead of a *.gsm file?

Provide a .raw file with that data in it, and Asterisk will play it. If 
it's going out a TDM channel, it will be converted to ulaw or alaw as 
required before it gets there.