Channel

A channel is one call path. Think of it as a single lane on a highway: one car at a time. Each live phone call on your system uses exactly one channel, so the total number of channels on your SIP trunk sets the absolute limit on how many calls can run at the same moment. If your trunk has 64 channels, you can have at most 64 calls going at once.

Because of this, channel count and Concurrent calls are tightly linked. The channel count is the capacity you bought; concurrent calls is how much of it you are using right now. When every channel is busy, the next call your dialer tries to place simply fails. On a busy floor this shows up as calls that never connect during peak hours, even though the leads are fine.

Buying the right number of channels

To size your channel count, start with how many agents you have and how aggressively you plan to dial. With Predictive dialing you launch several calls per agent, so you need more channels than agents. A rough rule is to give yourself headroom above your busiest expected moment so a brief spike does not push you into failed calls.

Channels are not the only limit. Your Carrier may also enforce a Calls per second (CPS) cap on how fast you start new calls, which is a separate ceiling. You can have free channels and still get throttled if you launch them too quickly. When you order a Trunk, confirm both the channel count and the calls-per-second rate so you know exactly what your dialer can do.