How do I Prevent Robo-Calls Into A Switchvox?

If you are getting nuisance robo-calls, you can prevent them by using an IVR. Usually, these type of calls have many different Caller ID names and numbers, so you cannot block by the Caller ID. 
To prevent robo-calls to DIDs that are routed directly to individual extensions, you can setup an IVR to route the calls to first. Then pass them through the IVR to the individual's extension number.

First, create an IVR that will have one Action: Dial Extension.

1. Go to Tools > PBX Features > IVR Editor

2. Create IVR Menu

3. Create Action > Dial Extension > Next (enter the user's extension number)

4. Save Settings

Now, create an IVR with the Option to press in order to connect the call:
In the IVR, include a sound file with instructions to press an Option number (for example, 1) and then create and Option to press 1 to connect the call. If the caller does not press 1, then the call will not connect to the extension and eventually will get a hangup. This will stop robo-calls from reaching an extension.

Then, under Modify Options, use these settings: 
Invalid Option Settings, you can leave this at the default settings which will send the call back through the IVR for legitimate callers.
Option Timeout Settings > Then go to the IVR Menu > select Hangup
Retry Settings > After retries, go to the IVR Menu > select Hangup

Next, assign an extension number to the IVR (you will need to create an extension):

1. Go to Setup > Extension > Manage

2. Click Create Extension 

3. Select Extension Type: IVR(Interactive Voice Response) 

4. Click on Create Extension 

5. Enter a new, unused extension number > Save IVR Extension

6. Route to IVR Menu (choose the IVR menu with the Dial Extension action you created) 

7. IVR Menu Entry Point: select IVR Menu Beginning

Finally, route the Incoming DID to an IVR.

For detailed instructions on setting up an IVR with Options click here
For detailed instructions on how to route an incoming DID to an IVR click here