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Administrator’s Guide for SIP-T2xP and SIP-T19P IP Phones
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The call flow scenario is as follows:
1. User A calls User B.
2. User B does not answer the call.
3. User A hangs up.
The call cannot be set up successfully.
User A Proxy Server User B
F1. INVITE B
F2. INVITE B
F3. 180 Ringing
F4. 180 Ringing
F8. 200 OK
F7. 200 OK
F5. CANCEL
F6. CANCEL