Hello > Kozauldong53 I don’t know what EC is or RE80.
EC means Eurocity. These are long-distance international trains between European cities. They are comparable to IC (Intercity) inside Switzerland. In Italy, seat reservations are mandatory and included in the ticket, not in Switzerland.
RE means Regional Express, 80 is the line number (same as a bus or subway line number). These are local trains with a few stops. No reservation is necessary or possible, but you must have a valid ticket before boarding the train.
Kind regards
Danhiel