Real-Time Caller Information Notification"" is a free supplementary service for wireless carriers that displays caller information of unknown numbers in real-time.
Currently, it is only available to users of KT carriers, and a free additional service, 'WhoWho Spam Notification' is provided.
<How to sign up and cancel> -Run or run the WhoWho app (v2.4.0 or higher)> 'See More' tab> General settings> Subscribe or cancel through 'Show real-time caller information' ☞ The menu is displayed only for users of KT carriers.