Communication

In the 24th century, this term primarily relates to subspace communication, which allows correspondence - live or recorded - to be transmitted at exceptionally fast subspace speeds. The latest advances in Federation communications technology include such diverse areas as holographics and micro-wormhole facilitated transmissions.

Subspace Communications

Mathematicians discovered the concept of a subspace within a space continuum centuries ago. The concept is alive in physics today, in theories that our space-time may have eleven or more dimensions - three space dimensions and time, plus seven more that are "curled up" within a tiny sub-atomic size scale, where they conveniently explain mysteries of the forces of physics. Starfleet Communications has utilized the principles of subspace to invent equipment which generates signals that can travel faster than the fastest starship. 1

The maximum possible velocity of signal propagation in the 24th century is Warp 9.9997, which is significantly faster than any starship. A network of subspace relays within the Federation territory ensures that no inadmissible signal decay occurs in case of long distance communication. Unlike an electromagnetic signal, which travels at the speed of light, the speed of a subspace signal depends on its amplification, and without the subspace relays the signal would eventually "resurface" and slow down to the speed of light. 2

Subspace signals can carry visual as well as audio and text data, though at differing ranges for solid copy. Simple text has the longest unaided range, with audio and visual data using more bandwidth and thus having lesser and lesser ranges, respectively. Combined audiovisual data streams are very wideband, and suffer extreme degradation from attenuation over the signal path, even on subspace channels. At the normal EM spectrum, they have a range of a few hundred kilometers at most.

Even personal communicators and combadges use subspace technology, in order to avoid EM interference and ensure reliable communication over long distances without the use of relaying stations. 3

(Note: The above is primarily conjectural and completely non-canonical. Subspace is a convenient way the Star Trek writers use(d) to make starships traveling at warp speeds not arrive somewhere some years before their signals.)