| 摘要 |
<p>PURPOSE:To prevent power from being applied in mistake when a CD signal is lost due to a fault of a MODEM or disconnection of a cable. CONSTITUTION:When power is applied to a controller whose power is controlled by a communication host device connecting to a MODEM 1 via a line, a carrier (CD) signal is reset. A CD signal monitor section 2a of an automatic power controller 2 monitors a CD signal and a data set ready (DR) signal and when the DR signal is set and the CD signal is set from the reset state, a power application signal is outputted to the controller whose power is controlled to apply power to the controller. When the CD signal is reset and the DR signal is set, since the power is applied to the controller 3, power is not applied in mistake. Moreover, when the off-time of the CD signal is monitored and the off-time of the CD signal is within a prescribed time, a power application signal is outputted.</p> |
