A memory has a plurality of memory cells, a serial address port for receiving a low voltage high frequency differential address signal, and a serial inputoutput data port for receiving a high frequency low voltage differential data signal. Thereby, the user can use the functions of the head mounted display and handset conveniently. Each pipe is equipped with a smaller internal pipe arranged concentrically to provide an annular space which receives the gas and supplies it to the diffusers. The system passes the list of references to a verifier that verifies each reference and outputs a list of verified references.