There was, as a result, a distinct chance that things might get interesting. The ship watched the Liseiden fleet crawl closer. Much further off than they’d ever have imagined possible, it had already begun to monitor some of their comms traffic.
...
Finally one of them said, “Sir, we ... may be approaching the sort of distance the Culture ship can start to read our comms.”
“This far out?”
“–encrypted, aren’t ... isn’t it?”
“Precautionary principle applies, team. Officer?”
The obvious, inter-ship comms traffic ceased. The Mistake Not ... considered dedicating an effector to the lead vessel to monitor it internally, but there was a tiny chance they might spot it doing so – a tiny chance increased by the possibility the fleet carried tech filched on earlier Scavenging sorties – so it didn’t.
Hours of patient waiting later, the Liseiden fleet of large, boxy-looking ships finally dragged itself into the Ry system, hauled up into a rather quaint orbit around the clinker sun with the warp-engine equivalent of loud clanks and clouds of black smoke, and – finally – rendezvoused officially with the Culture ship Mistake Not ...
- Hydrogen Sonata, Chapter Three: (S -23)
Distince isn't clearly specified but some hours eariler they were light years away,
The Liseiden hadn’t been forthcoming regarding the identity of the approaching fleet’s commanding officer, or even which ships would make up the fleet in the first place, but from the largest ship’s warp signature – hideously obvious from light years away – the Mistake Not ... had determined hours earlier that it was the Gellemtyan-Asool-Anafawaya, a Collective Purposes Vessel (First Class) and fleet flagship representing the last word in what the Liseiden were capable of building.
- Hydrogen Sonata, Chapter Three: (S -23)
And it still had to wait several hours for them to arrive after they turned off their comms as mentioned in the above feat.