What is ACD?
ACD (Automatic Call Distribution) is a phone system feature that places incoming calls in a queue and distributes them to available agents according to set rules. It is the core of most inbound call centers.
How it works
When a call enters a queue, the ACD checks which agents are logged in and free, then picks one using a distribution method: longest idle, round robin, fixed order, simultaneous or skills-based.
If nobody is free, the caller waits in the queue with music or announcements, such as their position. After a time limit, overflow rules send the call to another team, a voicemail or a callback.
The ACD records each step, which feeds reports such as wait time, abandon rate and calls handled per agent.
Why it matters
01Even workload
Calls are shared across agents instead of always hitting the same person.
02Shorter waits
The next free agent takes the next caller, with no manual dispatching.
03Measurable service
Queue data shows whether staffing matches demand.
Allo and ACD
Allo distributes calls across a team by ringing everyone at once or in cascade, with overflow to another group, a mobile or the AI receptionist.
Related terms
The terms that usually come up in the same conversation.
All glossary terms
Frequently asked questions
The IVR talks to the caller and finds out what they need. The ACD then decides which agent gets the call. They often work one after the other.
An ACD method that sends the call to the agent who has been waiting the longest since their last call, to balance the workload.
Small teams usually need a simple version: a shared number that rings the team at once or in order, with a fallback when nobody answers.