Check ZAND and ZANDE - There are settings in there related to hold music in a variety of situations - you can set it to say a prerecorded "please hold the line" message, I think there might be some tinny default music as an option, and then there is the regular hold music setup that sbcsu outlined where you have to connect a music source to an analog port through an impedance adapter and specify the pen of that port as your HMUSIC using RCSU. I was messing around with this during a class I was in last week - I found out it is possible to use hold music or the canned message on hunt groups as well so the user doesn't have to listen to ring no answer untill their call gets answered.
If you have a 4000 V7 you can go into the portal and all of the documentation for the entire system is in there - you can look up ZAND and ZANDE in there and see what the parameters do, as well as RCSU for setting up recordings.
As iamnothere mentioned above, if you are lucky enough to have a softgate you can use .wav files without having to interface any equipment.
Don Bruechert, Voice Comm Analyst II
CareTech Solutions @ Holy Family Memorial
Manitowoc, WI, USA