The DMD4 is an MP3 Message on Hold player designed for business messaging and music on hold applications. Messages and audio files can be played play from a USB. Upon reaching the end of the current MP3 file, it will automatically replay the file. If there is more than one file on the SD card the DMD4 will continually play each message in turn and then restart with the first file.

Free software is available for all Natcomm digital audio products to prepare and transfer files to a USB pen drive. A unique feature is the ability to encrypt files so that creative content cannot be easily replicated or played elsewhere. Files are automatically numbered to set the desired sequence of play.

The DMD4 has a 3.5mm mono jack for audio output and a volume control on the underside of the enclosure. The package comes with a USB pen drive, power adaptor and user guide.