Old call panel of a bourgeois house

A pretty and large appeal board of a bourgeois house. To call the office or kitchen staff. The principle of operation: the panel was installed in the kitchens or in the pantry, the owner of the house pressed a call button located in the room where it was located. In the office a light was displayed on the board coupled with a bell. This ingenious system was connected by small electrical wires. The light indicated the room where the household staff were asked to intervene. This painting was installed in mansions, borge houses, manors and company... Wooden painting in very good condition given its age dimensions with its support 37 X 32 dimensions of the square 34.5 X 29.5 dimensions of the glass 24.5 20 depth 8 cm.