The Care and Feeding of ISDN4BSD
12.3 Program Parameters	12 Setting up the	12.5 Available Scripts

12.4 Audio Format

The audio data format in use in Europe is A-Law, the other format used in other parts of the world is -Law.

Several short audio files are part of i4b and are coded in A-Law format, they can be found in the directory lib-isdn in the isdn4bsd distribution and have the file ending .al. (Note the audio format was changed between version 0.71 and later versions, the old .g711 audio files are incompatible with the newer .al audio files. They can be converted using the g711conv utility: ``cat oldfile.g711 | g711conv -r > newfile.al'').

The audio format which is available at the /dev/i4btel<n> interfaces can be configured by using the program isdntelctl(8).