The IntelliTouch MOH-500e is the easiest way to connect an external audio source to a multi-line phone system! The IntelliTouch Music On-Hold 500e (MOH-500) adds on-hold audio capability to ordinary single or multi-line phones. For years, what has been the "Holy Grail" of on-hold audio technology is now an affordable reality for any size business. The MOH 500e works with virtually all single and multi-line phones, and the new non-KSU corded and cordless phone systems (cordless systems require use of a head set). Just one unit provides music-on-hold capability on one to four lines and up to 16 different phone extensions. All you need to do is add your own audio source like a CD player , an MP3 player or other type of digital on-hold audio player. The MOH 500e works just like the on-hold audio feature on big, expensive, PBX and KEY phone systems. Just push the HOLD button on any extension and the MOH 500e grabs the line and plays on-hold audio to it*. To release the on-hold condition, just pick up any phone extension. It's that simple. Connection is similar to connecting a telephone answering machine, so installation is essentially plug and play.