AMD (answering machine detection)

Answering machine detection, often shortened to AMD, is a technique for estimating whether an answered call reached a person or an automated answering service. Implementations may analyse timing, silence, greeting length and audio characteristics after connection. The result is a classification used by a dialling workflow, rather than a direct statement from the receiving telephone network.

Detection involves a trade-off between speed and accuracy. Waiting longer can provide more evidence but may create an awkward pause for a person who answers. A short greeting, background noise, an interactive voice menu or a voicemail greeting can complicate the decision. False classifications therefore need a defined handling policy. Teams evaluating AMD should inspect real outcomes and distinguish machine detection from network answer status. An answered call in signalling records may still be voicemail. Operational rules should also consider any applicable restrictions on abandoned calls, recorded messages and automated outreach in each destination market.