Abstract: A time clock housing has a back plane circuit providing parallel circuit connections between identical pins on a plurality of circuit board connectors mounted on the back plane. This permits mounting any circuit board to any connector. The time clock includes a basic configuration of components as follows: a power supply, a floppy disk controller, a central processing unit, a ROM, a RAM, a real time clock having its own battery, an input/output circuit, an interface circuit, a keypad, a card reader, a liquid crystal display and an internal printer. The time clock optionally includes components as follows: a backup battery, a hard disk controller and hard disk, a video display circuit, a modem and a local area network circuit. Connectors may also be provided for connecting other devices to the time clock to enter data or receive data.