What is a manual telephone switchboard?

A manual telephone switchboard is a device used in early telecommunication systems that enables operators to connect calls by plugging and unplugging telephone lines. Operators would use a series of jacks and plugs to establish connections between callers, often using a system of lights or indicators to manage incoming and outgoing calls. This system was fundamental before the advent of automated switching technology, allowing for personalized call handling and management. Manual switchboards were widely used in the early to mid-20th century before being largely replaced by automated systems.