Call Distribution

What the ACD does

The ACD group, know as agent group in the Vodia PBX, is used to automatically distribute calls to a group of extensions. The ACD connects calls one after another to a group of agents. If there are too many calls for the agents, the ACD puts the caller into a waiting list and pulls the first one out as agents become available.

There are several algorihms available for connecting the calls. In the most simple case, the administrator can explicitly specify the preference for agents. Alternatively, the system can pick the agent that was the longest time idle, establishing a fair scheduling for the agent group. The system can also just roll dies to select the next available agent (random selection).

Each ACD can have a priority. This makes it possible to give callers priority access to agents that are logged in to several ACD. This is typically used for premium customer lines in busy call centers.


Agents can receive their calls on any of the devices that are associated with their extension. This is ideal for distributed groups that work from office, home or any other location with a Internet or phone line. The group management can choose the best device for the agents.

A special feature was added for cell phones. Calls to the extensions cell phone can be enabled on group and extension level, providing maximum flexibility where to serve incoming calls. When receiving the call, the agent can be required to confirm the call by pressing a digit on the phone, so that the call does not get lost in the agents mailbox when the agent is not available. For example, this makes it possible to include real estate agents or taxi drivers in agent groups while they are on the road, tremendeously reducing the required staff to operate the ACD. The feature is not limited to cell phones, it can also be used with regualar telephone lines, forexample areas with limited cell phone reception but existing telephone lines.


Scoreboards are essential tools for measuring and motivating office staff to processing calls efficiently. The Vodia PBX provides real-time and offline information that helps to manage ACD groups.

Real-time reporting. The agents and selected managament accounts can use their web browser to monitor the calls that are waiting and connected. A brief summary shows how much time agents have spend on the phone and idle; the web page also contains information about the number of processed calls, the average and total call duration and how long callers had to wait on average before the call got connected to an agent.
Email summary. At the end of the day, the system can send emails to select email addresses that contains information about the activity of a ACD group on that day. Like the web interface life reporting, it contains information about the calls and their durations and the agent activity. The email may also contain the detail call data records for a detail view.

Headcount control

Agents can be part of multiple ACD groups. This is useful when there are several groups that have a skill overlap, or agents that have skills for several tasks. For example an agent with technical skills may be able to serve support calls and at the same time help out with marketing.

When none of the logged in agents answers a ringing call, the ACD can include additional overflow agents in the group of available agents. For example, managers that are usually not working for the group may then be included in this situation.

Agents can log in and log out using star codes from any phone or the web interface of the PBX. The manager can set threshold for minimum staff, disabling the logout code when the number of available agents is below a defined threshold. This can be useful in environments where geographically dsitributed teams are working together where it is hard to see how many agents are available. ACD group managers can also statically log their agents in.

Between calls, the administrator can give agents a certain amount of time. This is called the wrap-up time that the agent can use to take notes of the call, for example update the customer information in the CRM system.

Agents can be automatically logged out for missed calls. This makes it easy for small groups to manage availability, especially when agents forget to log out.


There are several ways callers can be redirected.

  • Redirection. Calls can be redirected based on time or user-initiated events to other destinations. The events can be defined for waiting callers or ringing calls.
  • Exiting the queue. Callers can use DTMF to leave the queue and move to other destinations. The event will be logged in the statistics for the group.
  • No agent. When all agents are logged out or are no longer registered, calls can be automatically redirected to a programmable destination.

The maximum number of calls for the queue can be defined to ensure that limited trunk resources are not overloaded. When that number has been reached, the ACD can send a busy signal to the caller, so that the trunk line gets cleared up. This feature is important when other trunks lines need to kept open for other high-priority queues or for other services.

Outbound calls

When agents place outbound calls, the PBX can associate the caller-ID of the ACD with the call and log the call in the statistics for the ACD.

Each ACD keeps a list of numbers that should be called. This list can be uploaded through the web interface. The agent can pick the next number from the list by dialling a star code. If the call connects successful, the agent can use the "pound" key to take the number off the lise; if the call was not successfully connected, the agent may put the number to the back of the list, so that the agent or someone else can try to call this number later.

This feature is also available from the users cell phone, enabling mobile outbound calling. Because of the simple next-function for outbound calling, it is easy to use this function from regular cell phones.

Music while waiting

Callers hear music on hold mixed with announcements that can be either uploaded (studio recordings) or recorded from an extension. The recordings are mixed with the background music on a lower volume, giving a caller a sophisticated call impression, even when annoucements are recorded in-house. The first annoucement is played back even if the caller would otherwise immedaitely ring at least one agent. Other annoucements are randomly selected.

When calls are recorded for the ACD group, the ACD can play a message that informs the caller about the recording. This is a legal requirement in some legislations, and a good practice in many environents.

The announcements can be mixed with position announcements so that callers are aware of their queue position.

The connection event for the PBX can be set to various points in the call to avoid unnecessary cost to the caller. For example, when the typical time to connect to an agent is short, the administrator can specify that the calls get connected qhen the agent pickup up the phone. This is a way to reduce cost for inbound calls when using toll-free numbers.

Agent group identification

Agents that are logging into several ACD need to know which ACD they are answering when a call comes in. The ACD provides several ways to achieve this, which can be mixed and matched:

  • Ring melody. ACD can be programmed to propose a specific ring melogy for a group. This way agents can tell the difference between a regular incoming call and a call coming into a ACD.
  • Caller-ID. The caller-ID of the caller can be exteded with the group name, so that VoIP phones that have only limited space for displaying incoming calls can include the group name along with the number of the caller.
  • IP-phone display. IP phones with large displays can just display the caller-ID of the caller and in a seperate line the caller-ID of the ACD.
  • DID-specific information. Each DID can be tagged with a special name, a descriptive text and a recording for the number. This is suitable for virtual offices where agents are taking care about a large number of clients. The name typically contains the clients company name, a description can be used with pop-up tools for PC or in the web browser. If there is recording available, the PBX will read out that recording after the agent has answered the call, but not yet connect the call to the caller. This is a great way to provide a "script" for the agent what to say as the welcome message for the specific office.

Address book

The domain address book can be used to remember callers. This can be used to automatically fetch client matter codes or customer ID for callers. Those codes will be reported in the CDR, which simplifies the billing process for professionals like lawyers that bill telephone calls.

The address book entry may also contain the last agent that was talking to the contact. When the caller calls into the ACD, the ACD checks if the agent is available and prefers to connect the caller to that agent again. This makes it possible to keep the customer context and save time for callers to explain the case.