Most FTL communication is based on hyperstate signals. These share many features of EM radiation, including the ability to be modulated and transmitted, but can propogate through space at velocity above c. As the communication speed increases the energy cost goes up exponentially, so realtime communication is impossible everywhere, and even in the core systems delays are measured in hours. More distant colonies tend to have less powerful transmitters, and can be days, weeks, or even months out of date, depending on their power generators and distance from Earth.

Hyperstate transmitters are expensive, but not excessively so and all starships, right down to shuttles and EEVs carry FTL comms. The transmission speed for smaller craft is usually very slow, roughly 100c, but capital ships and liners can produce signals travelling at up to 300c. Planetary transmitters are obviously more powerful, ranging from 250c for a standard colony transmitter, up to 1200c for the most massive Earth based transmitters. Note that while fast signals are difficult to generate, they are just as easy to receive as any other.

The big problem with FTL communications systems is that the signals degrade if sent through any significant atmosphere. This means that interstellar gas limits transmission range to around 15 lightyears, and that signals cannot be sent from within an atmosphere. Most colonies use satellites or outposts which convert conventional radio into FTL signals. This unfortunately makes it easy to knock out FTL communications by destroying all communications satellites.