In the tower is the simple arrangement: the printer sits next to the console and connects with a 9-pin to RJ45 adapter. Slips are torn off in the tower and handed down or collected.
Trackside puts the printer where the drivers actually pull off. The printer talks to a wireless RS232 unit, which links back to the console, so there is no cable between the two. It needs mains power at the printer end.
The trackside arrangement is what a busy program usually ends up with, because the alternative is somebody walking slips down between every pair.
The printer itself is the same either way, and ships with the serial interface, ribbon and paper.