When shopping for Time Clock to be used with Time and Attendance software, you need to ask yourself if it is import for the Time Clock to continue functioning if there is a power failure in the building where Time Clock is installed. For a smaller organization, it might not be as important; in such cases, a supervisor can manually mark down the time employees come or leave work and later manually input this information into Time and Attendance software. For a larger organization, you might consider getting a backup battery which will power your device when there is a power failure. Most Time Clocks have internal memory and will store all registrations until your Time and Attendance software downloads the information.
The simplest solution is to get a UPS and plug your Time Clock into this UPS. This setup will do the job and for most Time Clocks, it is the only choice. Some Time Clocks, like HandPunch by Ingersoll Rand, have an option to get internal battery backup. This option includes not just a simple battery, but it comes with a special battery controller board. This board tells the reader when it is running from the battery and not from direct power. When there is a power failure and a HandPunch device switches to the backup battery source, it goes into a sleep mode. When an employee comes to the reader, he or she pushes a button and the reader wakes up. Then, after the Time Clock is idle for few minutes, it will go back into the sleep mode and hence preserve the battery. With this setup, HandPunch can run for several days without power.