| 摘要 |
<p>PURPOSE:To realize data signal transmission and reception between other terminal equipments and a control part by disconnecting an output transistor (TR) which is in a continuous on-state from a signal line automatically in an unbalanced type transmitting circuit used for an air conditioner. CONSTITUTION:When the TRQ2 is on continuously for a specific time or longer owing to the H holding of transmission data SD, short-circuiting of the TRQ2, etc., a capacitor C1 is charged continuously by the comparison output of a comparator CP1. The terminal voltage (c) across the capacitor C1 reaches a level H after the specific time determined by the time constant of a resistor R6 and the capacitor C1 and a diode D1 is turned off to cut off the bias voltage to a TRQ3, which then turns off continuously. Consequently, the TRQ2 is disconnected from the signal line L2 and the volage is inverted in level to a level L to permit free data signal transmission and reception between other terminal equipments TE2-TEn and the control part CT.</p> |
