The CCK-3104 Cypress synchronized display clocks are used to display the time from a master clock panel or access control system. Using an RS-485 twisted pair network, up to 32 clocks can be wired together in series and driven from a single time source. Clock drivers are available to provide compatibility with various access control panels, as well as an RS-232 driver for general computer applications. Dimensions 13.5? x 7.5" x 2.25"