Zones are just collections of channels. Typical radios can hold thousands of channels. To keep large numbers of channels manageable, they can be organized into zones. Usually, these zones represent a geographical area and all repeaters in that area are then grouped into zones. Of cause, a single channel can be added to multiple zones. Please note that for many radios, channels can only be accessed via a zone. That means, a channel that is not a member of any zone may not be accessible.
The zone table is defined within the configuration file as
Zone Name VFO Channels 1 "KW" A 1,9,11,12,14,8,55,15,4,5,6,20,21,22,19,48 1 "KW" B 1,3,2,81,82,84,85,86,87,88,89,90,91 2 "Berlin DMR" A 10,9,11,12,34,35,31,32,33,27,28,29,30,38,39 2 "Berlin DMR" B 1,3,2,81,82,84,85,86,87,88,89,90,91 3 "Berlin FM" A 20,21,19,18,22,23,24,25 4 "Potsdam" A 42,43,44,45,46,47,40,41 7 "Leipzig" A 75,76,72,71,73,70,74,77,78,80,79,69 8 "Simplex" A 1,3,2,81,82,84,85,86,87,88,89,90,91
The zone table starts with the keyword "Zone" and ends with an empty line. The remaining keywords (Name and Channels) are ignored but are part of the self-documentation of the configuration file. The first column specifies an unique identifier for each zone. This can be any integer as log as it is unique. The second (Name) column specifies the name of the zone as a string. Any string is valid here. The third column specifies the VFO (either A or B) for that zone. This allows to specify different channels for the two VFOs of the radio. For example, it allows to specify a list of repeater channels for VFO A and some simplex and calling frequencies on VFO B. The fourth column contains the comma-separated list of channel IDs for the zone anc VFO. A reference to any channel-type can be used here, analog and digital.