In telecommunication, the term operational service period has the following meanings:

1. A period during which a telecommunications service remains in an operational state.

Note: The operational state must be defined in accordance with specified criteria.

2. A performance measurement period, or succession of performance measurement periods, during which a telecommunications service remains in an operational service state.

Note: An operational service period begins at the beginning of the performance measurement period in which the telecommunications service enters the operational service state, and ends at the beginning of the performance measurement period in which the telecommunications service leaves the operational service state. Source: from Federal Standard 1037C and from MIL-STD-188