PalmOne designed the included earbud for use with the phone audio system, not the music audio system therefore, music will not play over the earbud that comes with the Treo. Palmone is however selling a separate headset with two earbuds that is intended for music purposes. Also, many third parties now offer "2 in 1" headsets that can play music and use a microphone.
One reader notes: "The earbud from previous Treo models (180, 270, 300) will work to play music, although the quality is (as expected) not great. This was the same type of earbud used in many Nokia handsets, so they may work too. Note that these earbuds will not work properly for making phone calls. The microphone does not work; the Treo uses its internal microphone instead."
