Apparatus and method for multicasting emergency alert message in broadcast signal to companion device

A primary device (PD) for communicating with at least one companion device (CD), the PD comprising:

• a broadcast interface to receive a broadcast signal including an emergency alert message (EAM), wherein the emergency alert message (EAM) includes identification (ID) information of the emergency alert message (EAM), priority information of the emergency alert message (EAM), and description information of at least one emergency event;
• and
• a network interface to send the emergency alert message (EAM) to a multicast group address such that the at least one CD is able to join a multicast group for the emergency alert message (EAM) based on the multicast group address, and send at least one message comprising capability information for representing capabilities and capability group required for decoding and presenting content to the at least one CD, a first value included in the capability information is used to represent video type information, a second value included in the capability information is used to represent audio type information and a third value included in the capability information is used to represent internet link information.