What is the connection between switching systems commonly referred to as?

The connection between switching systems is commonly referred to as a trunk. In telecommunications, a trunk serves as a dedicated communication path that connects switching offices or systems together, allowing for the transmission of multiple signals simultaneously. Trunks are essential for efficiently managing call traffic over long distances and are designed to handle many calls at once, which optimizes the use of the network’s resources.

The significance of trunks is highlighted in how they facilitate the interconnection of various switching systems, enabling effective communication between different parts of a network. This is crucial in maintaining robust and reliable telecommunications services, allowing users to connect seamlessly regardless of their geographic location.

The other choices refer to specific types of connections or systems within telecommunications but do not represent the overarching concept of inter-system connectivity the way trunks do. For example, tie lines are typically used for connections between different locations for private networks, FX lines relate to foreign exchange voice communications, and key systems refer to a type of telephone system used primarily in small businesses where multiple lines can be accessed easily by users without needing a switchboard.