A channel is a single voice line.
In the same way a single Telkom analogue line at home would only allow one person to make a call at a time.
1 analogue line = 1 digital channel
1 Telkom line = 1 Euphoria voice channel
So if you have an office of 25 people we would suggest having 8 channels to ensure there is always a channel available when a staff member needs to make or receive a call. We would never allow less than 4 channels on a Cloud PBX to ensure smooth functioning at all times such as conferencing and call transferring.