Outbound call control flow

When the system makes an outbound call, its control flow these steps:

1. Fetch the starting VXML file according to startvxml or starturl.
   
   In the call request, you can specify startvxml or starturl. The difference is that starturl is usually used for dynamically generated content, and startvxml is for static VXML files.
    
2. Apply dialing rule to the phone number
   
   You can set the dialing rule from Setup > Options from the gateway main menu.
    
3. Dial the phone number if there is dial tone on the line
   
   If the phone line is a digital line, or the phone line is not connected correctly, or someone else is using the same phone line, the system reports "Line Occupied".
    
4. Detect the line status, such as no answer, line busy, answering machine, live human pick up
   
   You could record the line audio by turning on "Record Initial Dialing" from the gateway. The recorded audio file is saved under C:\Program Files\Voicent\Gateway
    
5. Fetch the starting VXML files for answering machine if the call is answered by an answering machine. The initial starting VXML fetched is discarded.
    
6. Execute the starting VXML file after the gateway detects a live human pickup (someone says "hello"), or after it detects the answering machine beep.
    
7. The gateway interacts with the person called according to the VXML application
    
8. The gateway calls the endvxml or endurl after the VXML application finishes. The system default endvxml or endurl is an null op.
    
9. The gateway disconnect the call.
   
   Sometimes the person hangs up the phone in the middle of the VXML application. In this case, the gateway will detect the disconnected line condition and stop the application.
    
10. The gateway saves the call status