Here you can configure the Music On Hold files that will be
played. You can configure various 'Classes' of Music on Hold, which are
used in Queues. The idea behind that is your 'default' MOH is standard
music, and your various queues can have different 'hold' music while
they're waiting.
Simply select 'browse' and pick a MP3 file on your system. Then click 'Upload'. It will appear in the list of MOH files below.
With the release of FreePBX 2.5, Music On Hold comes with the new feature "Add Streaming Catagory." This addition to the Music On Hold module allows the Integrator to offer MOH streamed from the Internet or via the Line IN port on a sound card as a catagory.
In this example a Police Scanner is connected to a Line In port on a FreePBX 2.5.0 / Asterisk 1.4.21.2 system. The directions used to get Audio in and available are located here - http://www.sthomas.net/go/blog/view/38 NOTE: Skip editing musiconhold_X.conf. Use the GUI.
This example uses a scirpt created in /usr/sbin/ called "ast-playlinein" and it is used to control the parameters of "arecord" which is the program doing the heavy lifting here. Pointing at the script was all that was needed.
Streaming from the Internet is not that different. A good link to get started is http://www.voip-info.org/wiki-Asterisk+config+musiconhold.conf