What device combines multiple inputs into a single transmission path for transport over one channel?

• A. Multiplexer
• B. Multi-point Teleconferencing
• C. MPLS
• D. Bridge

Answer: (A)

Multiplexing is the process of combining several input signals into a single transmission path so they can be carried over one channel. A multiplexer is the device that does this: it takes multiple inputs and outputs one combined stream that travels on a single line, with a demultiplexer at the far end splitting it back into the original signals. This technique makes efficient use of the available bandwidth by sharing the same medium among several signals, using methods like time-division or frequency-division multiplexing. The other options refer to different functions: multi-point teleconferencing is about connecting multiple sites for a meeting, MPLS is a routing technology that uses labels to forward packets, and a bridge links network segments without merging multiple inputs into one channel.