Analog stations have a virtual feature button 18 configured in the endpoint template as a conference button. Unless this button is removed in the configuration, it will be the button that is used on Communication Manager, and conferencing users will be allowed. Device Adapter maps between the base operation (hook flash) and the button function.
UNIStim, M3903, M3904, and M3905 stations program the conference button as button 18. However, this is a soft key in the context-sensitive map. It is made available only when a call is active.