Circuit Switching

Definition of Circuit Switching

Circuit switching is a communication method used in telecommunications where a dedicated physical communication path is established between two devices for the duration of their conversation. This path remains exclusive and constant, ensuring a reliable connection with minimal delays. The traditional landline telephone systems primarily used circuit switching for voice communication.


The phonetic pronunciation of “Circuit Switching” is: /’sɜrkɪt ‘swɪtʃɪŋ/ (in the International Phonetic Alphabet)”sir-kit swich-ing” (in more familiar terms)

Key Takeaways

  1. Circuit Switching establishes a dedicated physical communication path between two devices for the entire duration of their conversation, ensuring a fixed and continuous transfer of data.
  2. During the conversation, the established circuit reserves the entire bandwidth, reducing efficiency, as the reserved capacity cannot be used by other signals or users, even if there is no data being transmitted by the connected devices.
  3. Circuit Switching is well-suited for applications that require constant, stable connections, such as voice calls, but may be inefficient for data transfer where continuous transmission is not necessary, like email or web browsing.

Importance of Circuit Switching

Circuit switching is an important technology term because it refers to an essential method of communication that has been utilized in telecommunication networks since the early days of the telephone system.

It involves the establishment of a dedicated, end-to-end communication path between the sender and receiver, ensuring the availability and consistency of a connection during its entire duration.

This dedicated connection facilitates the seamless transfer of data, voice, or video over communication networks.

While circuit switching has been largely replaced by more advanced packet switching methods in modern-day networks for data transfer and internet usage, it still remains relevant for providing reliable and secure communication channels in certain situations and environments.

In summary, circuit switching highlights the evolution of telecommunications and the foundations of modern-day communication networks.


Circuit switching is a foundational networking technology that enables the establishment of dedicated communication channels between two entities within a telecommunication network. This technology serves the crucial purpose of providing a reliable and consistent connection for the duration of a communication session, making it an ideal choice for applications such as traditional voice calls and video conferences.

Circuit switching works by creating a physical path or circuit between the sender and receiver, which is reserved exclusively for their use throughout the duration of the communication. This ensures that the quality and availability of the channel remain constant, free from interference and congestion that may be affecting other parts of the network.

The primary strength of circuit switching lies in its ability to maintain a consistent and predictable level of service quality. For example, when used in the context of landline telephone systems, circuit switching provides users with a dependable means to engage in clear, uninterrupted conversations without having to worry about dropped calls or fluctuating call quality.

While this technology has its roots in the analog telephone systems developed during the 20th century, it has since been adapted to accommodate digital communications, as well. Despite competitive alternatives such as packet-switching, circuit switching continues to offer unique benefits in certain use-case scenarios, particularly those that demand a consistent and stable level of performance between the communicating parties.

Examples of Circuit Switching

Circuit switching is a technology that has been used for many years to establish dedicated communication paths between devices over a network. Three real-world examples of circuit switching are:

Traditional Telephone System (Public Switched Telephone Network – PSTN): The most common example of circuit switching is the traditional telephone system, where a dedicated physical communication path is established between the caller and the receiver for the duration of a call. When you dial a phone number, the network establishes a connection through multiple switches to create a direct path between you and the person you’re calling, allowing voice signals to travel between both parties uninterrupted.

Integrated Services Digital Network (ISDN): The ISDN is another telecommunication network that is based on circuit switching. Introduced in the 1980s, it was designed to provide digital transmission of voice, video, and data over the existing telephone network. ISDN uses digital switching technology to establish a dedicated circuit between the calling and called parties for the entire duration of their conversation, allowing higher quality, more reliable connections than traditional analog systems.

T1 and E1 Lines: T1 (in North America) and E1 (in Europe) lines are types of digital transmission systems that use circuit switching to provide a dedicated communication channel between two points on a network. These connections often provide a reliable, high-speed data link between businesses and Internet Service Providers (ISPs) or between different branches of a large organization. The circuit switching technology ensures that the entire bandwidth of the T1 or E1 line is reserved exclusively for the connected devices, guaranteeing a consistent level of service and avoiding congestion that might occur in packet-switched networks.

FAQ: Circuit Switching

1. What is Circuit Switching?

Circuit Switching is a traditional telecommunications technology used to establish a dedicated communication path between two devices, typically for voice and data communication. The path is established for the duration of the connection, and no other traffic can use it during that time.

2. How does Circuit Switching work?

In Circuit Switching, a dedicated physical communication path is established between two devices when they need to communicate. This path is reserved for their exclusive use and stays in place for the duration of the call or data transfer. Once the connection is terminated, the path is disconnected, and the network resources are freed for other connections.

3. What are the advantages of Circuit Switching?

Some advantages of Circuit Switching include:

– Guaranteed Quality of Service (QoS) as resources are dedicated for the entire duration of the connection.

– Low-latency communication as data does not need to be packetized.

– Predictable connection times as there is minimal setup delay.

4. What are the disadvantages of Circuit Switching?

Some disadvantages of Circuit Switching include:

– Inefficient use of network resources since the entire path is reserved, even when not in use.

– Limited scalability as the number of paths establishes an upper limit on the network’s capacity.

– Potential for single points of failure if a network element along the dedicated path fails.

5. How does Circuit Switching compare to Packet Switching?

Circuit Switching differs from Packet Switching in several ways. Circuit Switching involves establishing a dedicated physical path between devices, while Packet Switching splits data into packets that are sent independently over a shared network. Circuit Switching provides guaranteed Quality of Service but is less efficient in resource utilization than Packet Switching. Packet Switching is more scalable and can handle multiple connections simultaneously.

Related Technology Terms

  • Connection Establishment
  • Dedicated Communication Path
  • Signaling Protocols
  • Call Routing
  • Time-Division Multiplexing

Sources for More Information


About The Authors

The DevX Technology Glossary is reviewed by technology experts and writers from our community. Terms and definitions continue to go under updates to stay relevant and up-to-date. These experts help us maintain the almost 10,000+ technology terms on DevX. Our reviewers have a strong technical background in software development, engineering, and startup businesses. They are experts with real-world experience working in the tech industry and academia.

See our full expert review panel.


About Our Editorial Process

At DevX, we’re dedicated to tech entrepreneurship. Our team closely follows industry shifts, new products, AI breakthroughs, technology trends, and funding announcements. Articles undergo thorough editing to ensure accuracy and clarity, reflecting DevX’s style and supporting entrepreneurs in the tech sphere.

See our full editorial policy.

Technology Glossary

Table of Contents

More Terms