Which group definition involves limiting access based on time parameters?

The correct choice, which involves limiting access based on time parameters, is schedules. Schedules in electronic access control systems are specifically designed to define time-based restrictions for when certain access permissions are active. This means that individuals or groups may only gain access to certain areas during designated times. For instance, a schedule may allow access to specific users only during regular business hours, while restricting access outside of those times.

In contrast, user groups refer to collections of individual users that share the same access rights, without a direct tie to time limitations. Access groups typically organize users and their corresponding access permissions but do not inherently address time constraints. Access zones define physical or logical areas within a facility where access rights apply but similarly do not incorporate time-based restrictions. Thus, the function of time-limiting access is unique to schedules within electronic access control systems.