At 650 au the local star is going to be pretty dim. For our sun, 422,500 times dimmer than at Earth. That's dimmer than night with a full moon. Solar power woul

At 650 au the local star is going to be pretty dim. For our sun, 422,500 times dimmer than at Earth. That's dimmer than night with a full moon. Solar power would be about 3 milliwatts per square meter. If you're setting up an interstellar communication network, it might make sense to have one really built up solar system (presumably ours) where you have all the massive infrastructure for power production, and then rather low mass transceivers in distant solar systems with little or no infrastructure can still function.