It helps in preventing call systems from being overwhelmed. It also helps in preventing callers from becoming caught in a call loop.
Key Takeaways
- A PBX (Private Branch Exchange) is a telephone system that allows internal communication within an organization. At the same time, an ACD (Automatic Call Distributor) is a software system that manages incoming calls and distributes them to the appropriate agents.
- A PBX can handle internal and external calls, while an ACD is used only for incoming calls.
- A PBX is used in larger organizations with multiple departments, while an ACD is commonly used in call centers and customer service organizations.
PBX vs ACD
Private Branch Exchange (PBX) is a private telephone network that enables employees to make internal calls and receive external calls without rerouting to a public phone provider. Multiple calls cannot be handled at once. Automatic Call Distribution (ACD) is a system that connects multiple external calls to agents within an organisation. The calls are distributed to specific agents to target inquiries.

For the agents to work with their supervisor or another agent to service the client appropriately, the PBX includes numerous team collaboration solutions such as screen sharing,
Some of these capabilities, such as call transfer or screen sharing, can be performed by agents without the knowledge of the consumer on the line.
Calls on holiday are automatically sent to voicemail, but calls received from numbers with certain prefixes may be directed to agents who can help callers in specific languages or who are familiar with a specific location.
Comparison Table
Parameters of Comparison | PBX | ACD |
---|---|---|
Full form | Private Branch Exchange | Automatic Call Distribution |
Function | A PBX allows employees of a big organization to receive and make calls without relying on the switching and routing services of a public phone provider. | The automatic call distribution system (ACD) connects the company’s internal resources with outside callers. |
Traffic jam | In a PBX system, traffic congestion may develop. | In the ACD system, there will never be a traffic jam. |
Capacity | Less number of lines | Multiple calls can be handled at once, and the source is identified. |
Real-time reporting | Does not include | Includes real-time reporting |
What is PBX?
The term “Private Branch Exchange” stands for “Private Branch Exchange.” A PBX is a phone switch with customized software that is located at a specific corporate location.
The PBX is the “machine” that directs incoming calls, allows a company to transfer calls to different extensions, and stores all of the requirements for how a business phone system should function.
Time and technology, on the other hand, have altered the consumer telephony environment, with the Open-Standards-based IP PBX serving as the flag-bearer.

What is ACD?
Since the 1950s, when PBX equipment routed calls using switchboard principles, many iterations of the ACD have existed.
The Rockwell Galaxy Automatic Call Distributor, which used technology based on a method invented by Robert Hirvela, introduced it into widespread usage in the mid-1970s.
The abbreviation “ACD” stands for “Automatic Call Distribution.” ACD is a switch as well as an application. It is in charge of accepting, holding, queuing, delivering, and reporting high-volume phone calls.
There are two types of ACDs: freestanding and C.O. (central office) based ACDs. Supporting highly specialized systems with stand-alone ACD is beneficial. It has features like monitoring, real-time reporting, and sophisticated routing systems.
Main Differences Between PBX and ACD
- PBX does not have many features, whereas ACD is a more sophisticated system that includes monitoring capabilities, real-time reporting, and complicated routing systems.
- PBX is inefficient, but ACD offers a precise call routing system and ensures higher customer satisfaction.
- http://tarrani.net/mike/docs/TrafficEngineering.pdf
- https://ieeexplore.ieee.org/abstract/document/8631894/
Sandeep Bhandari holds a Bachelor of Engineering in Computers from Thapar University (2006). He has 20 years of experience in the technology field. He has a keen interest in various technical fields, including database systems, computer networks, and programming. You can read more about him on his bio page.