Zones
Hi there,
While I do not know the specifics of what system/agency you are referring to, here goes.
Many models of Motorola radios, both trunked and conventional, use a terms such as zone and mode to organize "channels." The concept of "zone" on such radios can be thought of as being like a "bank" on a scanner. Motorolas usually refer to channels as "modes" so someone might say zone 1, mode 2, for example. Which would be put the channel switch on "2" while selecting Zone /bank 1.
Zones can be used to organize different radio systems on which a given radio might communicate, or simply different repeater sites falling under the same trunked system. For example, if the system is Type II, but not "smartzone" (which enables automatic switching between repeater sites), a radio might be programmed with a few different zones, one for each location that the user might be operating in. In this case, the channels/modes within the zones might well be duplicates of each other (e.g. the same talkgroups).
Hope this helps!
Jean