Which SIP response code indicates the called party is Busy?

Which SIP response code indicates the called party is Busy?

• A. 200 OK
• B. 404 Not Found
• C. 486 Busy Here
• D. 480 Temporarily Unavailable

Answer: (C)

In SIP, the response that directly indicates the called party cannot take the call because they are currently occupied is 486 Busy Here. This code is used in response to an INVITE to tell the caller that the callee is busy and cannot accept the call at the moment. Other codes shown are not the same: 200 OK means the invitation succeeded and the call was answered; 404 Not Found means the requested user or resource isn’t found; 480 Temporarily Unavailable indicates the user is not reachable right now, but it’s a broader, non-specific unavailability rather than a definite “busy.”

In SIP, the response that directly indicates the called party cannot take the call because they are currently occupied is 486 Busy Here. This code is used in response to an INVITE to tell the caller that the callee is busy and cannot accept the call at the moment.

Other codes shown are not the same: 200 OK means the invitation succeeded and the call was answered; 404 Not Found means the requested user or resource isn’t found; 480 Temporarily Unavailable indicates the user is not reachable right now, but it’s a broader, non-specific unavailability rather than a definite “busy.”