It is suitable for customers in pan-law enforcement, airports, railways, property, smart parks and other industries. In addition to solving the limitation of users' call distance through public network intercom, it also provides rich applications of multimedia data services, such as WIFI, Bluetooth, GPS, photography, video, NFC, etc., to realize the perfect integration of voice and broadband services for customers. The design of the small screen allows users to see the current channel more intuitively without taking off the intercom.