Digital device and method for providing additional service by using the same

One or more processor-readable storage devices having processor-readable code, the processor-readable code which, when executed by one or more processors, performs a method of providing an additional service of a mobile communication terminal, the method comprising:

• receiving a command from a user;
• transmitting a first identity code and a first authentication information corresponding to a communication operator to a first communication network device corresponding to the first identity code, when the command corresponds to a subscriber identity module;
• and
• transmitting a second identity code and a second authentication information corresponding to an additional service operator to an additional service providing device corresponding to the second identity code via the first communication network device in one case and via a second communication network device which does not correspond to the first identity code in another case, when the command corresponds to an additional service identity module;
• wherein the subscriber identity module includes the first identity code and the first authentication information and the additional service identity module includes the second identity code and the second authentication information, and
• wherein the communication operator provides a communication service, and the additional service operator provides an additional service including at least one of a video game, a music and a broadcasting program.