G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
G08B5/00—Visible signalling systems, e.g. personal calling systems, remote indication of seats occupied
G08B5/22—Visible signalling systems, e.g. personal calling systems, remote indication of seats occupied using electric transmission; using electromagnetic transmission
G08B5/221—Local indication of seats occupied in a facility, e.g. in a theatre