4.0" Digital Clock, 24V. The 24VDC (V-D2425/V-D2440) series clock is a reliable, economical option, working with the Valcom Digital Communication 2-wire system. The 24VDC/110VAC (V-D11025/V-D11040) series clock is a state-of-the-art bar display timepiece, which outperforms the competition's clocks. All of Valcom?s digital clocks feature an exclusive, high efficiency, super-bright LED display. The clocks feature immediate corrections for time change. Digital clocks are available in wall, flush or double mount with multiple levels of programmable brightness. The low voltage model has a wide dynamic range and can work on both AC and DC power sources.