Vendor Highlight Archive

Automatic call distribution (ACD) is a system that distributes both incoming and outgoing calls to a specific group of agents usually employed in a contact centre.


ACD systems have call routing and call processing logic, which can direct calls based on the calling number, or the called number.    


  • An example of calling number logic may be calls from a specific geographic area routed to specific agents.
  • An example of called number logic may be calls to differant free phone numbers which are routed to specific agents within the same contact centre.
  • An example of outbound calling logic is where calls are automatically placed based on an overdue payment, when the subscriber answers the call is routed to the next available agent.

 ACD systems are usually deployed with IVR (Interactive Voice Response), where the caller is prompted to press 1 for sales 2 for support, etc. Once the selection is made the ACD system either queues the call, or forwards the call to the next available agent based on the routing criteria.


ACD systems are also deployed using CTI (Computer Telephony Integration). CTI reads the calling number from the ACD transaction and can look up a customer database, which may contain address, purchase history, or other information. This enables the agent answering the call to help the customer faster since all the customer details will automatically populate their terminal.


With the evolution of more advanced and powerful computers, every ACD system today, is controlled using micro processor routing logic. Early systems from the 1970's used simple mechanical rotary distributor circuits, to connect calls to available agents, airline reservation systems are the earliest adoptors of this type of technology. Today ACD systems are configured using advanced call flow scripts.  

ACD Systems use different routing logic algorithms to determine how calls are directed to agents. Typical scenarios include:


  • First Available
  • Longest Idle
  • Round Robin

In addition to the above, ACD systems also use agent skills as preference for routing calls, as well as routing logic, depending on an agents training and ability. For example an agent who has english as a second language will only be routed english speaking callers when the waiting time in the queue is at a maximum level.



When ACD system exhaust the supply of available agents, calls are held in queues. A contact centre supervisor will monitor the queue depth, and agents performance to handle as many calls as possible, to reduce the waiting time.