In telecommunication an attempted call is termed a seizure; the answer-seizure ratio is defined as 100 times the ratio of answered calls, i.e. the number of seizures resulting in an answer signal, to the total number of seizures:
Busy signals and other call rejections by the telephone network count as call failures. However, the inclusion in the ASR accounting of some failed calls varies in practical applications. This makes the ASR highly dependent on end-user action. Low answer-seizure ratios may be caused by far-end switch congestion, not answering by called parties and busy destination circuits.
- ITU SG2 Recommendation E.411: International network management - Operational guidance.