You must declare the number of channels you intend to use, and are licensed to use. There is no default value. It is up to you to check your license agreement and enter the number of channel licenses that you intend to use on this system. These licenses are then allocated to the trunks that are physically attached to your system until all the licenses are used up. For example, if you have two E1 trunks, but declare only 50 licenses, you will be able to use 30 channels on the first trunk, but only the first 20 channels on the second trunk.