To change Music on Hold:
Press the PROGRAM Button
Press the HOLD Button
When it asks for your password enter:
Your password and then hit #
Press the 6 key
Press the 3 key
Press 1 to select source (see below)
Press 3 to select volume
Enter the MOH source, 591#, 592#, 593#, or 590# for an external source.
← How do I change the music on hold?