Cause Q.850Réponse SIP
1 unallocated number404 Not Found
2 no route to network404 Not Found
3 no route to destination404 Not Found
17 user busy486 Busy here
18 no user responding408 Request Timeout
19 no answer from the user480 Temporarily unavailable
20 subscriber absent480 Temporarily unavailable
21-nonusr - call rejected603 Decline (cause location is user)
21-usr - call rejected403 Forbidden (cause location is non user)
22-nondiag - number changed (w/o diagnostic)410 Gone
23 redirection to new destination410 Gone
26 non-selected user clearing404 Not Found
27 destination out of order502 Bad Gateway
28 address incomplete484 Address incomplete
29 facility rejected501 Not implemented
31 normal unspecified480 Temporarily unavailable
34 no circuit available503 Service unavailable
38 network out of order503 Service unavailable
41 temporary failure503 Service unavailable
42 switching equipment congestion503 Service unavailable
47 resource unavailable503 Service unavailable
55 incoming calls barred within CUG403 Forbidden
57 bearer capability not authorized403 Forbidden
58 bearer capability not presently available503 Service unavailable
65 bearer capability not implemented488 Not Acceptable Here
70 only restricted digital available488 Not Acceptable Here
79 service or option not implemented501 Not implemented
87 user not member of CUG403 Forbidden
88 incompatible destination503 Service unavailable
102 recovery of timer expiry504 Gateway timeout
111 protocol error500 Server internal error
127 inter-working unspecified500 Server internal error
Default (any other)500 Server internal error