symbian os及通讯技术术语全解上

　　symbian os和一些相关资料，内容不少，而且有些很专业。刚刚才收集整理了一份 技术术语白皮书，在这儿先放上来，大家共享。 　　1g 　　in mobile telephony, first-generation systems were analog, circuit-switched. voice links were poor, handoff unreliable, capacity low, and security non-existent. 1g systems are not now under active development – indeed, in some areas 1g spectrum is being auctioned for 2g and 3g use. 　　在移动电话技术中，第一代系统是模拟的电路交换系统。语音连接很差、越区切换不可靠、容量小且不具备安全性。目前，已不再积极开发1g 系统— 实际上，在某些地区，1g 频谱正针对2g 和3g 用途进行拍卖。 　　2g 　　in mobile telephony, second-generation protocols use digital encoding and include gsm, d-amps (tdma) and cdma. 2g networks are in current use around the world. these protocols support high bit rate voice and limited data communications. they offer auxiliary services such as data, fax and sms. most 2g protocols offer different levels of encryption. 　　在移动电话技术中，第二代协议使用数字编码，其中包括gsm、d-amps (tdma) 和cdma。2g 网络目前正在全世界使用。这些协议支持高比特率语音和有限的数据通信功能。它们提供多种辅助服务，如数据、传真和sms。大多数2g 协议提供不同级别的加密。 　　2.5g 　　in mobile telephony, 2.5g protocols extend 2g systems to provide additional features such as packet-switched connection (gprs) and enhanced data rates (hscsd, edge). 如果喜欢symbian os及通讯技术术语全解上请收藏或告诉您的好朋友.