This function hangs up one or more calls in the specified states

DWORD NetworkDropCall(
DWORD dwFlags
);

Parameters
dwFlags
[in] This parameter is indicating the calls that need to be dropped. This parameter can be a combination of the NETWORK_FLAGS_DROP. The following table shows the values the parameter can take.

NETWORK_FLAGS_DROP_ACTIVE drops the active call
NETWORK_FLAGS_DROP_HOLD drops the call on hold
NETWORK_FLAGS_DROP_OFFERING drops the offering call
NETWORK_FLAGS_DROP_OUTGOING drops the outgoing call
NETWORK_FLAGS_DROP_ALL drops all calls

Return values
Zero indicates success. A negative error number indicates that an error occurred. For additional error information, enable the library debug mode.

Remarks
After dialing has completed, several network messages are usually sent to the application to notify it about the progress of the call. See Network Callback Messages .

Sample

// Application entry point
int WINAPI WinMain(HINSTANCE hInstance,
    HINSTANCE hPrevInstance,
    LPTSTR lpCmdLine,
    int nCmdShow)
{
    // Load the TAPI Library
    if (LoadDynTapiDll(TEXT("\\DynTapiDll.dll")) != ERROR_SUCCESS) {
    MessageBox(0, TEXT("Cannot load DynTapiDll.dll . Try to reinstall this sample."), TEXT(""), MB_ICONERROR);
    return 0;
    }
    DebugMode(1);
    // Init the Library network component
    if (NetworkInit(hInstance) != ERROR_SUCCESS) {
    UnloadDynTapiDll();
    MessageBox(0, TEXT("Error using the network, does this device have a phone module?"), TEXT(""), MB_ICONERROR);
    return 0;
    }
    // Set callback for events
    SetNetworkEventCallback((tpfnCallback)PhoneCallback);
    // Try dialing a number
    if (NetworkDialNumber(TEXT("555111222"))!=ERROR_SUCCESS) MessageBox(0,TEXT("Can't dial number"), TEXT(""),MB_ICONERROR);
    else {
        Sleep(10000);//wait for the call to connect
        NetworkDropCall(NETWORK_FLAGS_DROP_OUTGOING | NETWORK_FLAGS_DROP_ACTIVE); //drop our call, not sure of it's status so drop both outgoing and active calls.
    }
    ...
    NetworkDeinit();
    UnloadDynTapiDll();
    ...

Requirements
OS Versions: Windows CE 1.0 and later.
Header: dyntapi.h.
Dll Library: dyntapidll.dll.