The HCM functional knowledge specific to Employee Time Management systems (e.g. Inform WFM, Kronos Workforce Central/Dimensions, SAP CATS, etc.).
Time systems entail the upload of a schedule, an employee clocking in (getting a feed from clock-in and clock-out), working in a job or jobs, then clocking out (or exception-based time where only exceptions are entered in).
The time system records breaks, calculates any required daily or weekly overtime, and then sends authorized hours to a Payroll system to pay employees (in our case SAP applies the rate to the hours calculation), and also sends a feed to the HR system to decrement time off balances, based on time off taken (vacation, sick, leave, etc.).
The heavy lifting for a time system is in managing the testing of different employee groups (calculation groups) such as exempt, non-exempt, and various unions for which these rules differ.