switching centre

communications

Also known as: switching office

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Last updated

July 14, 2026

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The term "switching centre" in telecommunications refers to a hub within the telephone network responsible for connecting calls. Early systems used manual switchboards where operators physically connected lines. Later, electromechanical switches like the Strowger switch and crossbar switch automated this process, allowing for direct dialing.

Modern telephone networks have evolved into a more streamlined, two-level hierarchy. Local offices, known as class 5 offices, connect directly to customers. Class 4 offices, previously toll and tandem offices, handle long-distance calls and are owned by interexchange carriers. With deregulation, the distinction between local and long-distance providers has blurred.

Furthermore, voice traffic can now be transmitted over data networks using packet-switching techniques like Voice over IP (VoIP) and Voice over ATM (VoATM), utilizing routers and ATM switches instead of dedicated circuits.123

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electronics
Optoelectronics
…signals arrive at a central switching office in optical form, it has been attractive to consider switching them from one route to another by optical means rather than electrically, as is done today. The distances between central offices in most cases are substantially shorter than the distance light can travel…
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…signals arrive at a central switching office in optical form, it has been attractive to consider switching them from one route to another by optical means rather than electrically, as is done today. The distances between central offices in most cases are substantially shorter than the distance light can travel…
Read More

telephone
The switching network
…to support such an organization, switching centres in the American telephone system were organized into three classes: local, tandem, and toll. A local office (or end office) was a switching centre that connected directly to the customers’ telephone instruments. A tandem office was one that served a cluster of local…
Read More
…to support such an organization, switching centres in the American telephone system were organized into three classes: local, tandem, and toll. A local office (or end office) was a switching centre that connected directly to the customers’ telephone instruments. A tandem office was one that served a cluster of local…
Read More