Wholesale voice
ASRAlso known as Answer-Seizure Ratio, Answer ratio
Definition
ASR (Answer-Seizure Ratio) is the percentage of call attempts that are answered: answered calls divided by total attempts (seizures), multiplied by 100. It is a core quality metric for trunks, routes and gateways, because a falling ASR reveals routing, capacity or network problems long before customers complain.
How ASR is calculated
ASR = answered calls ÷ call attempts × 100. If a route receives 1,000 attempts and 450 are answered, ASR is 45 %. Answered means the call received a 200 OK (connected), regardless of how long it lasted.
Because ASR includes busy, no-answer and invalid-number outcomes caused by callers, it depends heavily on traffic type and destination. A related metric, NER (network effectiveness ratio, ITU-T E.425), excludes user-caused outcomes to isolate network performance.
- Business-to-business traffic often shows a higher ASR than consumer or call-centre dialling.
- Compare a route with its own history and with other routes to the same destination, not with a universal target.
What a drop in ASR means
- A vendor route is failing or congested (look at SIP 503 and 486 responses in CDRs).
- Capacity limits are being hit.
- On a mobile line: a SIM with no balance, a lost registration, poor signal or a blocked SIM.
ASR is read together with ACD and PDD: a high ASR with a very short ACD can mean calls are being answered by announcements rather than people.
ASR in GSMCalls
GSMCalls shows calls, ASR, ACD and minutes live on the dashboard, per site and per device, and CDRs carry cause codes that explain failures. A sudden ASR drop on one device often points to a SIM or signal problem; see platform and features.
Frequently asked questions
What is a good ASR?
It depends on traffic and destination. Track each route against its own baseline and against other routes to the same destination.
Is ASR the same as NER?
No. ASR counts every attempt; NER excludes user-caused failures such as busy or no answer, so it reflects network performance more directly.
Do short calls count toward ASR?
Yes. Any answered call counts, however short, which is why ASR is always read together with ACD.