The present invention provides an ultra-mini and low cost refractive index measuring device applicable to biochemical measurements of an extremely minute amount of a sample. The inventive device includes Ultimate Karaoke Book, Karaoke Rental Systems, ProPlayer, Karaoke Shoppe Download Center, Karaoke Burning Station, Downloadable Karaoke CD+G Player, Video Library Pro, DRM and Licensing encryption engine, Pre-manufactured CD DRM. The coupler includes a first pair of rotatable latches for releasably securing the first trough member to the coupler, and a second pair of rotatable latches for releasably securing the second trough member to the coupler. The bipolar pulse generator further includes a bended Blumlein generator structure, in which an existing intrinsic \u201cstray\u201d transmission line is used to provide the bipolar pulse. A failing MS may attempt to receive a message addressed to the failing MS on the multiple-access forward rescue channel and have its connection rescued using the message information.