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GSM数码移动电话是90年代发展起来的采用时分多址技术(TDMA)的新一代数字式移动电话系统。它与俗称“大哥大”的模拟移动电话相比较,具有频带利用率高、保密性好、噪音小、不易被串机等优点。在GSM系统中,每一位移动用户都持有一张用户识别卡(SIM卡)。在SIM卡中,存有用?
The GSM digital mobile phone is a new generation of digital mobile phone system developed in the 90s using Time Division Multiple Access (TDMA). Compared with the analog mobile phone commonly known as “Big Brother”, it has the advantages of high frequency band utilization, good confidentiality, low noise and not easy to be serialized. In the GSM system, every mobile subscriber holds a Subscriber Identity Module (SIM). In the SIM card, saved?