A method includes transmitting, from a base station, a first request and receiving, from a transponder, a first code transmitted responsive to the first request. The method includes transmitting, from the base station, first encoded transmission information comprising a base station code encoded using the first code and a first identification. The base station transmits a second request, and a second code, transmitted by the transponder responsive to receiving the second request and encoded using a base station code extracted from the first encoded transmission information using the first code and the first identification, is received. Second encoded transmission information, including a second identification encoded using the second code, is transmitted from the base station. The second identification information may be extracted using the second code, access to a transponder memory region provided based on comparing the extracted second identification information to a stored version of the second identification.