He is no longer connected to the network by a fiberoptic cable, and so all his communication with the outside world has to take place via radio waves, which are much slower and less reliable. Going into The Black Sun would not be practical—it would look and sound terrible, and the other patrons would look at him as if he were some kind of black-and-white person. But there's no problem with going into his office, because that's generated within the guts of his computer, which is sitting on his lap; he doesn't need any communication with the outside world for that.