Denial of Collect Calls
You can configure the device to reject (disconnect) incoming Tel-to-IP collect calls and to signal this denial to the PSTN. This capability is required, for example, in the Brazilian telecommunication system to deny collect calls. When the feature is enabled upon rejecting the incoming call, the device sends a sequence of signals to the PSTN. This consists of an off-hook, an on-hook after one second, and then an off-hook after two seconds. In other words, this is in effect, a double-answer sequence.
This feature can be enabled for all calls, using the EnableFXODoubleAnswer "global" parameter, or it can be enabled for specific calls, by enabling this feature in a Tel Profile.
| ● | The feature is applicable only to FXO interfaces. |
| ● | If automatic dialing is also configured for an FXO port enabled with Denial of Collect Calls, the FXO line doesn't answer the incoming call (ringing) until a SIP 200 OK is received from the remote destination. When a 200 OK is received, a double answer is sent from the FXO line. |
| ● | Ensure that the PSTN side is configured to identify this double-answer signal. |