ACD (Automatic Call Distribution) is a system that automatically routes incoming calls to available operators based on predefined rules in a call center. It is a core technology that directly affects call center efficiency and customer satisfaction, and is one of the four key systems alongside PBX, IVR, and CTI.
ACD routing algorithms come in four main types. First, longest-idle-agent routing, which prioritizes the operator who has been waiting the longest, equalizing workload. Second, skills-based routing, which matches calls to operators based on language ability (Japanese, English, Chinese), specialty (technical support, billing, cancellation), or qualifications (financial product licensing). Third, priority-based routing, which gives precedence to VIP customers or high-urgency inquiries. Fourth, percentage-based routing, which distributes calls across multiple sites or teams at set ratios.
ACD works closely with IVR. After IVR directs callers ("Press 1 for technical support, 2 for billing inquiries"), ACD selects the optimal operator from those with the matching skill set. When integrated with CTI, customer information appears on the operator's screen the moment the call connects, enabling smooth handling.
Key KPIs for ACD management include answer rate (percentage of calls answered out of total incoming, target 80%+), average speed of answer (ASA, target under 20 seconds), and service level (e.g., "answer 80% of calls within 20 seconds"). Monitoring these KPIs in real time and adjusting operator staffing and routing rules is a primary responsibility of call center managers. Cloud PBX services often include ACD as a standard feature, with browser-based rule changes and real-time monitoring. See Call Center Quality Tips for operational best practices.