Abstract: A receiving section has one crystal resonator 122, an inductor 124 able to be connected in series to the crystal resonator 122, and a channel change-over switch 123 for switching whether the inductor 124 is connected to the crystal resonator 122 and the ground, or the crystal resonator 122 is directly connected to the ground, and an adjusting change-over switch 125. A transmitting section has one crystal resonator 321, plural frequency setting adjusting circuits 312,313 each including an inductor 314,316 for determining a frequency oscillated from an oscillator, and a switching connection switch 318 for switching and connecting one of the plural frequency setting adjusting circuits 312,313 to a modulating circuit 320 connected to the crystal resonator 321.

Abstract: A transmission antenna is formed on a transmission-sided board as an electric conducting pattern having a length of ¼(&lgr;/4)±20% of a wavelength, where the transmission-sided board mounts thereon a transmission circuit used in a frequency range defined from 700 [MHz] to 3 [GHz], and a portion of the transmission antenna, which is longer than, or equal to ⅔ of an entire length of the transmission antenna, owns a width wider than, or equal to &lgr;/400. And, an reception antenna is formed on a reception-sided board 202 as an electric conducting pattern having a length of ¼(&lgr;/4)±20% of a wavelength, where the reception-sided board mounts thereon a reception circuit used in a frequency range defined from 700 [MHz] to 3 [GHz], and a portion of the reception antenna, which is longer than, or equal to ⅔ of an entire length of the reception antenna, owns a width wider than, or equal to &lgr;/400.