Digital broadcast system and method of processing signal

A digital broadcast system and a method of processing a signal are provided to broadcast safety/security information of a telematics terminal through a broadcasting network and provide the information to unspecified people. When theft or a accident of a car is detected, a telematics terminal generates and transmits safety/security information at least including a number and current location information of a corresponding car. A broadcasting station configures the safety/security information received from the telematics terminal as mobile broadcasting service data and multiplexes the information with main broadcasting service data. The broadcasting station transmits the multiplexed data through a broadcasting network. A receiving system extracts the safety/security information from the mobile broadcasting service data transmitted from the broadcasting station and processes the extracted information. The receiving system outputs the processed information by one format among a text, voice and an image.