A WTO Member's trademark law refuses registration of a sound mark solely because it is not visually…

Article 15.1 defines signs capable of constituting a trademark broadly, but expressly adds that "Members may require, as a condition of registration, that signs be visually perceptible". A Member may therefore refuse to register sound or smell marks. Capability to distinguish is a necessary condition for registrability under TRIPS, not a guarantee of registration of every sign.