| 摘要 |
<p>A communications interface device (4) has circuitry for receiving digital signals in the form of characters according to a protocol defining that a communications link is initialized by a series of start characters, each having a specified duration. The receiving circuitry can assume a first state in which characters can be detected, and a second state in which detection of characters is not possible. Power consumption is higher in the first state than in the second state. The device can alternate the receiving circuitry periodically between the first state and the second state with a period shorter than the duration of the series of start characters. In each period the receiving circuitry assumes the first state for a time longer than the duration of a start character. A communications link is established if a character is detected. The power consumption can be reduced considerably without causing unnecessary inconvenience and time consumption for the user.</p> |
