The convergent phone

Past claims for Internet telephony have proved over optimistic, but the technology remains crucial to the future of the telecoms business. The author reports on how the industry is learning to live with the challenge of network convergence. The development effort required to deliver appropriate QoS levels and seamless interworking with the PSTN has been massive, and is ongoing. Within the closed world of single-company autonomous networks, or the confines of a company WAN/LAN, the technology is now practicable, but it's an open question as to whether VoIP will ever operate across multiple networks with the performance and reliability of the PSTN. Such reservations aside, the operational and service attractions of VoIP will make the successful management of convergence the most important challenge for network operators over the coming decade     

The cellular phone scare

The scare about cellular phones causing brain cancer is examined in the light of what is known about: effects of RF radiation on human beings. The concern focused on the portable cellular phones that can be slipped into a pocket or purse, because their antennas lie right alongside a user's head. Standards for electromagnetic (EM) radiation exposure are discussed, and research results to date on the effects of EM radiation is summarized. Changes to phones that might reduce exposure and the potential impact of public fear on the market for cellular phones are considered     

The unpredictable mobile phone

A year-long ethnographic study of the use of mobile phones in Jamaica was conducted during 2004. Our findings, which are almost the exact opposite of the expectations that appear in The Economist and other sources in early 2005, are that, in Jamaica at least, the phones are not used to obtain jobs or to help individuals become entrepreneurs. For quite different reasons, however, mobile phones have become central to the survival strategies of the lowest income population. To understand why this should be, we need to examine how the phone fits within other forms of communication, and how both the phone and the phone call are evaluated. This is tantamount to asking how one person values their communication with another and under what conditions does communication become an end in itself?     

The unpredictable mobile phone

A year-long ethnographic study of the use of mobile phones in Jamaica was conducted during 2004. Our findings, which are almost the exact opposite of the expectations that appear in The Economist and other sources in early 2005, are that, in Jamaica at least, the phones are not used to obtain jobs or to help individuals become entrepreneurs. For quite different reasons, however, mobile phones have become central to the survival strategies of the lowest income population. To understand why this should be, we need to examine how the phone fits within other forms of communication, and how both the phone and the phone call are evaluated. This is tantamount to asking how one person values their communication with another and under what conditions does communication become an end in itself?     

The great blue box phone frauds

The use of an electronic device called the blue box to exploit a loophole in the nation's long-distance telephone network is recounted. To avoid long-distance charges, blue box users first dialed long-distance directory assistance, 800 numbers, or numbers that carried only a small toll charge. After the user dialed his number and was connected to a long-distance trunk, the blue box emitted a 2600 Hz tone, clearing the equipment at the tandem trunk's receiving end and signaling the switching equipment that the call had been completed and the trunk was waiting for a new call. The local central office, however, had not received its call termination signal, so the local central office did not disconnect the caller from the long-distance network. The permanent solution to the blue box problem proved to be common channel interoffice signaling (CCIS), a method rejected in the 1950s as too costly and difficult to implement     

The mobile phone meets the Internet

Fifteen years ago mobile telephones were an exotic extravagance. Today, as cellular phones, they are often given away as freebies in support of marketing schemes and product promotions. Having become a mainstream voice communication medium, they are poised to take on new challenges, transmitting (fairly) high-speed data, video and multimedia traffic as well as voice signals to users on the move. The technology needed to tackle the challenges is known as third-generation cellular telephony. From this viewpoint, the early analog cell phones are labeled the first generation, and similar systems featuring digital radio technologies are labeled the second generation. These newer phones have appeared alongside of, and in some places have replaced, their analog forebears     

GSM手机标准概况

介绍了GSM移动通信系统的发展历史，详细阐述了GSM标准和国际GSM手机认证的情况。     

Packet phone

Why would anyone want to transmit voice over the creaky, packet-based Internet? In this paper, the author looks for some answers to the great conundrum of modern communications     

手机阅读

人们的传统阅读时间已经被现代生活的快节奏打散,使得阅读在现代人的生活中显得力不从心,而移动阅读恰恰可以充分挖掘传统阅读无法覆盖的碎片时间,如工作之余、上班路上、排队等候等等,使人们的时间得以有效利用。拥有一个具备通信功能的电子书阅读器,成千上万册书即可尽收眼底,这极大地刺激了读者的阅读欲望。手机阅读正在改变着人们学习知识和获取信息的方式。     

多功能手机将成为手机市场竞争新焦点

2006年是多功能手机加速发展的一年．各种款式的多功能手机为用户带来了全新的体验。有关专家认为．2007年，多功能手机将成为手机市场竞争的新焦点。欧洲市场去年销售了5000多万部多功能手机，占多功能手机全球总销量的41％。在未来5年内．欧洲将继续占有最大的销量份额，而亚太地区将进一步巩固其全球销量第二的位置。多功能手机将把终端市场打造得更为精彩，使消费者的生活更加丰富多彩。集多种功能于一身的智能化手机，将成为无线通信技术领域一个新热点。[编者按]     

手机病毒与移动通信安全

目前手机在日常生活中使用得越来越广泛.尤其是随着移动通信技术向3G/B3G的迅猛演进,手机的功能也越来越强大.但是与此同时,手机病毒也已经开始对移动通信系统构成严峻威胁.本文阐述了手机病毒原理、攻击方式、主要类型以及手机病毒的预防措施等几个方面的问题.同时针对手机病毒所带来的威胁,对整个移动通信安全机制的改进和完善提出了建议.     

手机病毒与移动通信安全

目前手机在日常生活中使用得越来越广泛。尤其是随着移动通信技术向3G／B3G的迅猛演进．手机的功能也越来越强大。但是与此同时．手机病毒也已经开始对移动通信系统构成严峻威胁。本文阐述了手机病毒原理．攻击方式、主要类型以及手机病毒的预防措施等几个方面的问题。同时针对手机病毒所带来的威胁．对整个移动通信安全机制的改进和完善提出了建议。     

Small-cell mobile phone systems

The three major small-cell mobile phone systems now entering commercial use are described. These are the Bell system in the greater Chicago area, the Motorola system in the Baltimore/Washington area, and the Japanese system in the Tokyo area. The Bell system is described in some detail, including its procedure when reducing cell size, and the steps in setting up and in handing off a talking circuit. The major differences in the other systems are stated.     

打开手机看报纸 第五媒体雏形初现

最近，广东移动与新华社广东分社以及南方日报，广州日报和羊城晚报三大报业集团，强强联合推出的“手机报纸”正式“出版发行”。广东移动的4500多万用户从此又有了一种新的读报方式，     

Nokia 7600可拍照手机大拆解

本栏目将陆续推出电子产品拆解分析服务,每期以一个具有代表性的电子产品为例,拆解分析内部使用的模块、芯片等元器件的各种信息,包括每个元器件的类别、生产厂商、型号、功能、封装形式、I／O及管角数目,每类元器件在整个产品中所占的成本比例等,希望给电子工程师们在设计同类产品时在成本控制、功能实现及元器件选择上以参考。     

GSM手机的测试

概述GSM(全球移动通信系统)是由欧盟国家联合研制的一种数字蜂窝移动通信体制。GSM体制由于具有频谱利用率高、系统用户容量大、话音质量好、抗干扰能力强、保密性强等技术优势,我国自1994年开始大规模采用GSM技术建设数字移动通信网,并得到高速发展,到2002年年底我国移动通信GSM手机用户总数已超过2亿。GSM手机用户的每一次呼叫必须按GSM系统分配在指定的载波、时隙上通信,因此在GSM系统内使用手机的技术指标好坏会影响通信质量和网络效率。目前我国GSM手机进网测试执行的是标准YD/T884-1996《900MHz TDMA 数字蜂窝移动通信…