Patent ID: 7860238

Claim:
A communication terminal comprising: a battery pack including a battery cell for supplying power through a direct current (DC) signal path; a terminal main body driven by the power supplied from the battery cell, and providing at least one additional function to a user; and at least one additional function module electrically connected between the battery pack and the terminal main body, providing the at least one additional function to the terminal main body through a communication path, and including a plurality of additional function modules that are connected in a serial communication bus format, wherein the terminal main body comprises: an additional function processor for demodulating a signal received from the at least one additional function module and modulating a signal for transmitting the signal to the at least one additional function module so as to provide the at least one additional function; a power supplier for receiving power from the battery cell through the DC signal path to drive the terminal main body; a first blocking unit located on the communication path, and blocking inflow of the power supplied from the battery cell to the additional function processor; a second blocking unit located on the communication path, and blocking inflow of the signal transmitted to and received from the at least one additional function module so as to provide the additional function to the power supplier; and a controller for controlling the additional function processor and the at least one additional function module, wherein the battery pack comprises a third blocking unit located on the communication path and blocking transmission of a signal transmitting/receiving to/from the terminal main body to the battery cell.