What a channel is
A channel is the line connecting two gates in two different centers. When both gates of a channel are activated in a chart, the channel becomes defined, and both its centers are defined with it. A channel is a constant life force, a talent that is always "on".
Why channels matter
Channels decide the type, the authority and how the centers are connected. There are 36 of them, and each belongs to one of the circuits — Individual, Collective or Tribal. When a person has only one gate of a channel, they look for the other in other people — that's how attraction arises.