| 摘要 |
<p>The sensing circuits are integrated in on hybrid device to simplify the station line interface. The circuit charges the telephone fees exactly with a detection circuit detecting the inverted polarity of the station line, and prevents the collision of ring signal with a GND level detection circuit. The circuit includes a trunk matching unit (200) connected between the tip of the station line and ring terminal to transmit tone signals, a voltage detectors (201,202) for detecting the positive and negative voltage signal provided from the trunk matching unit (200), for filtering the voltage detected by a photo coupler, and transmitting to a latch and a multiplexer unit, and detection circuits (204,205) for detecting the busy and ring signals.</p> |
