I understand, that you can get an USB connector from cisco to add an MOH device, I assume this is to allow say, a multi cd player, to just play MOH continuously through the Callmanager(CUCM)
That is most correct my friend
If recorded or live audio is needed, MoH can be generated from a fixed source. For this type of MoH, a sound card is required. The fixed audio source is connected to the audio input of the local sound card.
This mechanism enables you to use radios, **CD players, or any other compatible sound source. The stream from the fixed audio source is transcoded in real-time to support the codec that was configured through Unified CM Administration. The fixed audio source can be transcoded into G.711 (A-law or mu-law), G.729 Annex A, and Wideband, and it is the only audio source that is transcoded in real-time.
The Cisco MoH USB audio sound card (MOH-USB-AUDIO=) must be used for connecting a fixed or live audio source to the MoH server.