A method and an apparatus accurately discriminates between speech and voice-band data in a communication network by calculating self similarity ratio values, which indicate periodicity characteristics of an input signal segment, andor autocorrelation coefficients, which indicate spectral characteristics of an input signal segment, to generate a speechVBD discrimination result. In one embodiment, upon accessing the memory system for a piece of data used by a first process, a latency manager determines the access time to acquire the piece of data in the memory system. In this case, preferably, the gate insulating film of the transfer MOS transistor has a thickness which is not greater than that of the gate insulating film of the capacitor MOS transistor. In response to the filtering, if the at least one received datum represents a valid command, the method includes converting the at least one received datum to identify the at least one instruction.