Don’t connect a CD player to your phone system – the audio output is 44,000 HZ when your phone system works at 8000 HZ – so for a start the audio will not be loud and clear – but low and distorted. Also, remember your on hold message plays continuously 24/7 – and CD player motors are not really designed to run non-stop. This basic telecoms-grade MP3 player has no moving parts and outputs audio perfectly matched to your phone system.