Particular embodiments provide an access gateway that facilitates communication between a plurality of access technologies. One or more of the semiconductor memory devices may detect a read command and a dummy read command in response to the command signal and the chip selecting signal and generate one or more preamble signals based on a calculated preamble cycle number. A wide range of functional groups is tolerated in this approach, and even complex alkenes click with the silane precursors. A ranging code generator is arranged for generating a ranging code.