Provided is an apparatus and method for low distortion display in a portable communication terminal. The method further includes assigning a code character to each of the password characters at an authorization site, transmitting the code characters assigned to the password characters to a remote client and authorizing a user at the remote client upon entry of the code characters corresponding to the password characters in the defined order. The substrate has a first conductivity type, a first side and a second side opposite to the first side. Therefore, the reliability for transporting the client byte number can be improved and an OPUk overhead byte space needed for transporting the client signal byte number can be saved.