User guide

August 2001 111
Handling Incoming and Outgoing Calls
Handling Incoming Calls
Handling incoming calls involves the following steps:
1. Detect an incoming call.
2. Handle call setup signaling.
3. Send control tones.
4. Answer the call.
5. Process the call, while monitoring for disconnect.
6. Terminate the call.
You can block a channel at any time to prevent further incoming
calls.
Detecting an Incoming Call
When the application is ready to receive a call, it calls
RHT_WAIT_LINE_ON. This function waits until the device
receives a seizure signal, then sends a seizure acknowledgment.
The function waits for an amount of time specified by the
RDG_LOCAL_ACK_GUARD_TIME parameter, then returns
an acknowledgment signal. The application is then ready to
receive digits. The series of events involved in detecting an
incoming call is shown in Figure 22.
Table 22. RHT_WAIT_LINE_ON Sequence
Action Duration
Receive seizure or ring
Send acknowledgment (if
required)
Wait RDG_LOCAL_ACK_GUARD_TIME
Send acknowledgment
Return