| 摘要 |
PURPOSE:To enable a MODEM unit to easily correspond to the change of its standard and to make it unnecessary to prepare specific shielding structure by using a hybrid IC constituted of mounting a DTE interface, a microcomputer, a MODEM circuit, etc., on metallic circuit board and a metallic base plate provided with common circuit parts to constitute the MODEM. CONSTITUTION:The MODEM unit is constituted of the hybrid IC 10 obtained by mounting the DTE interface, the microcomputer, the MODEM circuit, a transmitting amplifier, a receiving amplifier, and a dialer on the metallic circuit board 12 and the metallic base plate 20 provided with a modular jack, a light trounsformer, a bus connector, a ROM, and structure for connecting the hybrid IC. Namely, the circuit parts common to the MODEMs of all standards are formed on the base plate 20 and the MODEM hybrid IC 10 to be prepared in each MODEM standard is mounted on the base plate 20. Consequently, the MODEM unit can be allowed to correspond to the request of any MODEM standard with proper performance and the preparation of specific shielding structure is made unnecessary.
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