The discussion unit (10) for use in a conference system is disclosed, which is adapted to be connected to at least one second discussion unit (10). The discussion unit (10) comprises an essentially closed casing (410) and at least one exchangeable portion (420). The at least one exchangeable portion (420) is removably mounted to the casing (410) and at least partially covers at least one outside part (424, 412) of the casing (410). The invention allows for an easy first installation of the exchangeable portion (420). Nevertheless, after installation, the exchangeable portion (420) is difficult to remove by a user (preventing unintended removal or removal by vandalism or “play instinct”), but allowing for an easy exchange of the exchangeable portion (420) by an installer and/or a service technician.