Which SIP response indicates the callee answered the call?

Interview
1

Q. Which SIP response indicates the callee answered the call?

a) 202 Accepted
b) 181 Call Is Being Forwarded
c) 200 OK
d) 486 Busy Here

Check 🔎

:arrow_right: Correct answer: Letter c.

The 200 OK response is a final SIP response indicating that the callee has accepted and answered the call. This response is typically sent after the 180 Ringing (or other provisional) responses and is part of completing the call setup in the SIP INVITE transaction.

Once the caller receives this, it acknowledges with an ACK, and media (RTP) can begin.

Option Analysis:

a) :x: 202 Accepted
→ Incorrect. While it indicates acceptance, it’s for non-INVITE requests, such as subscription or messaging — not call answering.

b) :x: 181 Call Is Being Forwarded
→ Incorrect. This is a provisional (1xx) informational response indicating call forwarding is in progress — not call answered.

c) :white_check_mark: 200 OK
→ Correct. This confirms the callee has answered the call, finalizing the INVITE transaction.

d) :x: 486 Busy Here
→ Incorrect. This indicates that the callee is currently busy and did not answer the call.