You can set up the device screen to flash when a call is coming to make it easier for users with hearing loss to notice when someone is calling them.
When this setting is configured, the device screen flashes red and gray when someone calls it.
You can enable this feature from the web interface of the device. Read the Advanced Settings article for more information on how to access it.
First, select Settings from the menu on the left. Under Configurations, choose the following: