system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek] Even using Warp-speed, there are limits to how fast starships can travel, but they have no problems communicating at huge ranges. Why?

So throughout Star Trek ships and stations frequently communicate with places that are weeks or months travel away instantaneously.  Why is there no lag time? There are clearly limits to their range since in Voyager they use miniature short-lived worm holes to send messages from Star Fleet to Voyager when it's beyond the range of their communications, but there seems to be zero issues between say, Sisko on DS9 and his dad on Earth talking despite the huge range.

How does this work? Why do there communications work seemingly instantly up till the point where it just turns off?
gpt
Interstellar communications are done through subspace, which allows the signal to travel faster than light. However the signal can only travel within subspace for so long before it eventually 'bleeds' back out into normal space and is once again reduced to 'only' moving at the speed of light.

To get around this, most interstellar nations have constructed a network of subspace relays in and around their territory. These stations pick up a signal, amplify it, then send it on towards its intended destination. Thanks to extremely advanced computer systems, the entire process takes only tiny fractions of a second and so there is little to no lag noticeable, even over larger distances.