Can trunked radios do talkaround mode and skip the repeater entirely using the voice channels?
Or can they do a low power talkaround mode?
2 radios on the same talkgroup talk 1 on 1
Maybe conventional mode using voice channels (without repeater) like the radios do, using 8tac channels.
I realize they can operate conventionally in fail safe mode, when controller is down.
As others have said - there are various ways for doing these types of things.
Some "talk-arounds" are simply a different talkgroup on the system but still using the repeater (mostly for greater distance I would assume).
However, as you suggest, some systems (not really
on the system) - many very old - even have conventional frequencies for low power direct communications (typically analog). These bypass the repeaters in part because that may actually be why it is being used - the users cannot reach the repeater. Situations for us may include: interior building communication, units are out of their normal locations (another state or county), and/or they just don't want anyone to hear them talking (at least not normal users on the system).
In some cases, it would seem they discourage use of these channels because they are in completely different programmed radio "zones" which take more time and effort to switch to. Still, in other cases, for safety reasons, these "direct" channels are easily accessed within the same primary radio user zones - and it's just a turn of the channel knob.
Frequency usage for these non-repeater talk-arounds vary from location to location. Some jurisdictions have licensed their own frequencies while others use common VTACs, 8TACs, etc.
As far as 1 to 1 -- that sounds like what is called "private call". These typically go through the repeater but are direct radio to radio calls - almost like a phone call vs. a broadcast on a talkgroup where all users on that group can listen.