A. Choose number from contact or directly dial from the dial pad and press send key. If send key long press detected, answering incoming call will enable speaker otherwise enable handset only.
B. Dialer will dial to callback service number instead of number from A
C. Upon callback server reject the call or after xx sec timeout, dialer must disconnect the call.
D. Wait for call from callback service provider.
E. upon Answering any incoming call, after end of dialer activity, dialer will waits xx sec, and start to dial number from A ending with or without suffix. dialer active to monitor end call activity
F. End call detected, dialer will send end call string, wait for xx sec, terminate call and stops activity. Cycle completed.