G08B 7/068

Signalling systems according to more than one of groups [CPC: G08B3/00] - [CPC: G08B6/00]; Personal calling systems according to more than one of groups [CPC: G08B3/00] - [CPC: G08B6/00] using electric transmission {, e.g. involving audible and visible signalling through the use of sound and light sources calling personnel in a restaurant, e.g. waiter call}