Abstract: A surface acoustic wave device comprises a lower electrode provided on an elastic substrate, a piezoelectric film covering the lower electrode and an upper electrode provided on the piezoelectric film. The device is characterized in that the upper electrode comprises first and second double electrodes both opposed to the lower electrode.

Abstract: A power loading/unloading mechanism for tape record/playback apparatus which comprises a gear driven by a motor, a rack member associated with a tape pack inserted; a partly cut-out gear independent of the rack member operation system and interlocked with a cam member for advancing and retreating a head plate; an engaging gear driven by the motor and disposed so as to engage with the partly cut-out gear; a means for keeping the engaging gear from engagement with teeth of the partly cut-out gear; and an engagement operating means for detecting completion of tape pack loading and for putting the engaging gear into mesh with the teeth of the partly cut-out gear.

Abstract: A printing mask for use in printing on a board having a projection characterized in that a cavity member with a desired dimension is put on a screen tensed on a frame, a part of the screen surrounded by an open end of the cavity member is cut off, and thereafter, the other part of the screen is formed with a pattern to be printed.

Abstract: In a system for communicating data between two stations interconnected by way of a telephone line, a data transmission system wherein at least one of the stations includes a telephone set normally connected to said telephone line, a line changer, a data transmitter and a signal detector. When another station is called through the telephone set and a predetermined signal transmitted from said another station is detected by the signal detector, the line changer switches the telephone line from the telephone set to the data transmitter.