在局域网标准中，(28)与FDDI的MAC帧格式较为相似。(29)介质访问控制方法对最短帧长度有要求，(30)对传输线路最短长度有要求。长10km，16Mbit/s，100个站点的令牌环，每个站点引入1位延迟位，信号传播速度位200m/us，则该环上1位延迟相当于(31)m的电缆，该环有效长为(32)。

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Bluetooth is a universal radio interface in the(71)frequency hand that enables portable electronic devices to connect and communicate wirelessly via short-range, ad hoc networks. Each unit can simultaneously communicate with up to(72)other units per piconet. Moreover, each unit can simultaneously(73)to several piconets. Eliminates the need for wires, cables and connectors for and between cordless or mobile phones, modems, headsets, PDAs, Computers, printers, projectors, local area networks, and so on, and paves the way for new and completely different devices and applications. Technology Characteristics(74)symbol rate exploits maximum available(75)bandwidth。

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