A radiotelephone (100) is coupled to accessory (200) by way of a novel interface provided by connector (190). Accessory (200) is a headset including a microphone (220) and a speaker (230) that may be plugged into a jack in radiotelephone (100) and worn by the user. Accessory (300) provides an RS-233...http://www.google.de/patents/US6038457?utm_source=gb-gplus-sharePatent US6038457 - Apparatus and method for detecting and powering an accessory
