It seems as though they can switch modes from single frequency TRBO to multi frequency TRBO. When setup in single mode, 1 slot is control and one is voice.
Interesting
Depends on the system.
With Capacity Plus, there is a rest channel beacon every x seconds. There is no control channel/slot. With Connect Plus and Capacity Max, there is a control slot (typically slot 1 of whatever repeater is the active control channel). Can't speak of Capacity Max but I assume, which doesn't mean much, that like other Tier 3 solutions I've installed it is capable of being used in a single repeater capacity where one slot is control and the other is the only available "channel".
Now you have to be very mindful of these system as there's some migration going around. For example, a couple of months ago I upgraded one of my (three channel) Capacity Plus sites by adding an extra repeater and controller for Connect Plus. The channels got evenly distributed (so 4 slots are Capacity Plus voice and 3 are Connect Plus voice). As I migrate customers off of Capacity Plus, I'll move another repeater over to Connect Plus. However, withing the next year or so I'll also be installing two more repeaters for Capacity Max. As I offload Capacity Plus, I'll load either Connect Plus or Capacity Max depending on how many customers can upgrade but there is the potential to be running three different TRBO systems at a single site.