Google’s Lyra codec can already get down to 3Kb/s and be reasonably audible. It’s not a stretch to imagine within a few years we’ll be able to push that to below 1Kb/s.
Taking those two things together, I think it’s fairly reasonable to assume at least text and voice are within reach.
> The screen showed a color image with high resolution. Looking at it carefully, one realized the thing was a poor evocation…. Kjet recognized Owner Limmende and Jan Skrits, her chief of staff, but they looked several years out of style. Ølvira [the ship] was matching old video with the transmitted animation cues. The actual communication channel was less that four thousand bits per second; Central was taking no chances.
> [...]
> The picture was crisp and clear, but when the figures moved it was with cartoonlike awkwardness. And some of the faces belonged to people Kjet knew had been transferred […] The processors here on the Ølvira were taking the narrow-band signal from Fleet Central, fleshing it out with detailed (and out of date) background and evoking the image shown.
What they might be able to do is expand this to something like limited texting, or maybe down the line even non-realtime voice messaging.