 The Sega CD can only be used in conjunction with a Genesis system , attaching through an expansion slot on the side of the main console . Though the Sega CD is an add @-@ on , it does require its own separate power supply . In addition to playing its own library of games in CD @-@ ROM format , the Sega CD can also play compact discs , karaoke CD + G discs , and can also be used in conjunction with the Sega 32X to play 32 @-@ bit games that utilize both add @-@ ons . The second model , also known as the Sega CD 2 , also includes a steel joining plate to be screwed into the bottom of the Genesis , as well as an extension spacer to work with the original model of the Genesis . 
