| 摘要 |
The terminal peripheral has an interface circuit (12) to the telephone lines. The interface circuit is permanently connected and presents a high impedance to the telephone lines. The interface captures information in the form of analogue signals carried on the telephone lines. Another circuit (PG) connects the interface circuit in parallel with the remote control equipment (TT), which is connected in the usual way to the telephone line. A modem converts the analogue signals to digital form. A peripheral controller (14,16) receives the digital signals and provides any necessary processing. The high impedance of the interface circuit is provided by a series capacitor, which also blocks direct currents.
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