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友利电公司根据用户的要求,不断推出适应市场的产品。800MHz集群设备在美国最早只用作无线调度系统设备。在中国推广以后,用户多用于电话系统,为此友利电第一个生产出具有同电话网相联的800MHz集群系统,随后又根据急需双工手机的要求,第一个生产出800MHz集群系统的双工手机(SPS 330 TSD)。在同铁道部签定200个信道的合同之后,根据铁道部的要求开发了联网的ESAS系统,ESAS系统在1995年3月正式定型生产并在中国市场销售。 ESAS系统是第一个采用分布式控制方式实现自动漫游、全网达128个站、唯一身份码多于100万个的800MHz集群系统。近年来,随着中国蜂窝无线电话的进一步完善,专业网又回到对800MHz集群系统的调度功能的需要,尤其要求800MHz集群的调度联网功能,友利电公司又开发了具有多区调度的ESASⅡ系统。该系统除了具有原ESAS系统的多区电话联网功能外,还具有多区调度功能。
Friends of Lee Electric Company based on user requirements, continue to introduce market-compatible products. 800MHz cluster equipment in the United States only as a wireless dispatch system equipment. After the promotion in China, the users mostly used in the telephone system, for this reason, the first production of the Friends of the power with the telephone network connected 800MHz cluster system, and then in accordance with the urgent need of duplex mobile phone requirements, the first to produce 800MHz cluster system Duplex handset (SPS 330 TSD). After signing a contract of 200 channels with the Ministry of Railways, a networked ESAS system was developed according to the requirements of the Ministry of Railways. The ESAS system was officially finalized and marketed in China in March 1995. ESAS system is the first to use distributed control to achieve automatic roaming, the entire network of up to 128 stations, unique identity code more than one million 800MHz cluster system. In recent years, with the further improvement of China’s cellular radiotelephone, the professional network has returned to the need of scheduling functions of the 800MHz cluster system, and in particular, the dispatch networking capability of the 800MHz cluster has been required. In addition, Unilever has developed an ESASⅡ system with multi-area scheduling . The system in addition to the original ESAS system multi-zone telephone networking capabilities, but also has multi-zone scheduling capabilities.