Time clocks are devices that can be used to track the hours that an employee works. These devices were originally mechanical in nature, though electronic and computer-based time clocks have also been produced. The way a time clock functions is that each employee uses it to check in when arriving at work, and to check out at the end of the day. This data can then be used to calculate an employee's pay, and some modern units are even capable of making these calculations automatically. Time clocks traditionally made use of paper cards that were either punched or printed on, though radio frequency identification (RFID), biometrics, and other technologies such as magnetic cards, can be found in modern designs.
The first time clock was invented in the 1880s, and these devices have been in use ever since. Early time clocks were purely mechanical in nature, and there were a few different designs. Some of these early time clocks required each employee to dial in his or her own assigned number, after which a card within the machine would be punched with the time and day. Other designs allowed each employee to handle his own card, in which case he would be responsible for inserting it into the machine properly to receive day and time stamps. In addition to mechanical units, there are now a number of other designs, including software-based and self-calculating time clocks.
The most basic models simply create a record of the time each employee checks into and out of the workplace, but at the end of the pay period someone needs to add everything up in order to prepare the payroll. A self-calculating time clock is a unit that is capable of tabulating those hours automatically, which can be a big time saver for large companies. Most software-based designs also include this functionality, though other features are often present as well. Software-based time clocks can make use of remote check-in terminals, and they are typically networked directly into the computers of the payroll department.
Perhaps surprisingly, the same types of punch cards that have been around since the 19th century are still used by some modern time clocks, though a number of newer technologies are also used. An electronic time clock can require a personal identification number (PIN) for each employee, while other systems use magnetic cards that can be swiped over readers. Biometrics are sometimes used with time clocks as well, since requiring a hand print, or retinal scan, can cut down on abuse of the system. Another technology that can be used with an electronic time clock is RFID, which can track the arrival and departure of employees without requiring them to actually take any action other than walking through the door.