A digital multiplex is a broadcast transmission that combines several TV services into one digital signal, letting multiple channels share the same radio-frequency slot. Compared with analog television, where one channel usually occupied one frequency, multiplexing makes spectrum use more efficient and allows broadcasters to carry extra video, audio, and data services.
In cyber security and resilience discussions, the term matters because a multiplex is a dependency chain: encoders, transmitters, network links, and receiver firmware all have to agree on how the signal is packaged. If any part is misconfigured, outdated, or intentionally interfered with, viewers can lose service or see partial outages. Attackers do not need to “hack TV” in a dramatic way; jamming, spoofing, or exploiting weak operational controls can still disrupt availability. Defenders focus on redundancy, standards compliance, and careful transition planning to keep older and newer equipment compatible.