Privately owned switching equipment that allows communication within a business and connected to common lines from one or more telephone company central offices is known as ______ equipment.

• A. Private branch exchange (PBX)
• B. Public branch exchange (PBX)
• C. Central office switch
• D. Key system

Answer: (A)

The setup described is a private branch exchange. This is equipment owned by a business that handles internal calls between extensions and connects to external lines provided by the telephone company’s central offices. It centralizes control of how calls are routed, allows features like extension dialing and call routing, and can use multiple trunk lines to reach the outside world.

Why other options don’t fit: a central office switch is the telephone company’s equipment at the telco’s side, not privately owned by the business. a public branch exchange is the telco’s system serving many subscribers, not a private business tool. a key system is a smaller, simpler system for fewer lines and typically doesn’t provide the same level of trunk connections to multiple central offices or advanced routing features as a PBX.