6.2.2 Setting In-Band Mode

In in-band mode, the DTMF audio is not clamped (not muted) and DTMF digits are sent in the RTP packets.

Note: When a channel is opened, the DTMF transfer mode is in-band by default.

To set up a channel for in-band mode:

1. Open a channel using ipm_Open("ipmB1C1",NULL,EV_SYNC)
2. Set up the IPM_PARM_INFO structure and call ipm_SetParm( ) as shown below:

    IPM_PARM_INFO parmInfo;
    unsigned long ulParmValue = DTMFXFERMODE_INBAND;
    parmInfo.eParm = PARMCH_DTMFXFERMODE;
    parmInfo.pvParmValue = &ulParmValue
    ipm_SetParm(chdev, &parmInfo, EV_ASYNC) 

Figure 3 shows a scenario diagram for setting in-band mode.

Figure 3. In-Band Mode Scenario Diagram

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