Full duplex’s limitations
The main interest of "conference" mode is to allow to converse in an almost natural way without the need to request to speak by pressing a PTT ("Push To Talk"). However, this feature has the same limitations as the human conversation, in a vehicle for example: people who do not see themselves quickly tend to speak at the same time, creating multiple conversations. It is therefore prudent to limit the professional "conference mode" systems to three terminals, while many others may be in "listen-only" to participate in the conversation without interrupting it.