Because radio waves and other methods of transmitting information only travel as fast as the speed of light, using such methods for interstellar communication is completely ineffective. Even when communicating between two very close solar systems, the transmission time would be a matter of years. That’s where the cosmotransmitter comes in. Cosmotransmitters manipulate Cosmowaves in the same way as Cosmodrives, using them to transport not a physical object, but a ‘package’ of information across long distances. These packages travel across the same cosmowave streams that ships do, but they’re neither tangible nor visible to the naked eye, until another cosmotransmitter picks them up and converts them back into the message that was input.
Any spaceship of sufficient size usually has at least one cosmotransmitter built into the bridge. On the surface, they tend to be available for public use, similar to phone booths. Of course, many institutions have their own private ones as well.
Due to their lack of mass, the signals sent by cosmotransmitters travel faster than spaceships using cosmodrives, but it still takes an average of a week for a message to go from one end of the galaxy to the other. And since a message can't change its course once sent, they're particularly vulnerable to cosmowave storms, which can cause them to never arrive at all.
These delays add additional difficulty to running a sector-spanning faction. In a way, long-distance communication across Andreemea resembles how it was in medieval times, when communication with other countries was slow and unreliable.