If the SF-VIK004-S-2 KIT presents a problem when trying to establish the call, the image on the screen simply remains black when receiving the call from the external board.
1st Solution: Check if the board has the status "Inactivated", if it does, it means that the initialization wizard was not completed correctly.
Solution: click on the board, we will have a message indicating that the device will be activated, choose "YES" and wait a few seconds to check its operation.
Once the status is "ACTIVATE" you should check its operation.