Ship to Ship Communications
Subspace is the preferred method of communications for advanced races. It provides near instant video and audio comms. Additionally data can be sent between ships, such as co-ordinates etc. Communications can be established with any ship, planet or starbase (that has sub-space comms) within 10 light years. Messages can be sent (one way communications) to targets further away, but the response will not be instant. These signals are sent on by federation sub space relays.
The first step in a communication is to “Open a Channel” to a selected target. Valid targets are all ships, star bases and planets that the ship can see on its scanners (and that are within 10 light years). Unless encrypted (this can only be done between Federation vessels) these communications can be monitored by any other ship.
Another option open to the captain is to send out a message on all frequencies. Any ship receiving this message may decide to respond.
Messages sent are restricted to a few standard phrases (Answer Distress Call etc,).
Power Requirements
It takes 0.1MW to open a sub-space channel (and hold it open).