This image shows the main switch board for the Win Place and Forecast tote in White City London. It belongs to what a 1937 Referee newspaper article refers to as The World's Biggest Tote which can be read in the previous image of the Photo Gallery. The scanners are the two rows of circular devices which can be seen at the bottom of the equipment panels on the left and right hand sides of the central switchboard section. The Scanners are Time Division Multiplexers long before the electronic digital signalling methods that made TDMs commonplace. For a description of the scanners, overlap relays, Ticket Issuing Machine isolation switches and the Cut-out Relays look at the close-up image, which follows this one in the Photo Gallery.
There is a note on the rear of this photograph. It reads: Provision has been made for the addition of further panels of Distributors and Relays as required up to the maximum capacity of the Adding equipment.