Many modern devices today have an aux audio input, or auxiliary input jack. This enables one to plug in a hardware device directly to another hardware device, like your computer, for easy connection.
Because more and more people are enjoying music, an increase in the purchases for MP3 players and iPods has been evident. Even the old CD players are still being used by many people, too. Some will even like their music loud and use the speakers of any existing stereo equipment. The problem is that finding the right cables can be intimidating and if they were easy to find, some will be a very expensive purchase.