摘要 |
<p>Light emitted from one or more optical indicators, e.g. LEDs (11, 12) comes from the interface (13) itself, or close by it. A cylindrical optical conductor (8) is used, aligned along the axis at the interface. The rechargeable battery is built-in or replaceable. The interface is a USB- or other plug. The optical conductor is the cable or its sheath. Light passes down it, between its terminal plugs.</p> |