Communication is an important part of modern commerce, networking, and also useful in emergencies. Technology has come a long way, for sure, but space is a vast, vast place.
A modern commlink can network with other commlinks on a planet or to an orbiting nearby body. Celestial bodies are generally too far away, however, without assistance from a lightcomm.
Within a Star System
Lightcomm are communications satellites which can boost a commlink signal to light speeds. While this allows instant communication between a planet, its moons and nearby vessels and stations… the maximum speed of communications is light speed. This would mean that communications between Earth and a Jump ship arriving near Sol would have an eight-minute communications delay and a 14 minute delay for Earth to talk to Mars (when its close, or 22 minutes when its furthest away). For faster communications, use of a Drivecomm.
Between Star Systems
Drivecomm piggybacks off the Jump Drive within a Jump Gate or installed aboard a starship to create micro-singularities linked to another Drivecomm. Once the link has been established, communications is instantaneous regardless of distance. However, just like the Jump Drive, the communications are one-direction. So long as you are within 200,000 miles of the Drivecomm, the message will be delivered almost instantly via Lightcomm.