共查询到20条相似文献,搜索用时 109 毫秒
1.
2.
3.
4.
5.
6.
上海160综合信息服务系统上海声讯信息服务公司(上海200120)陈国峰1系统概述随着经济的发展和社会的进步,快捷、方便、准确地掌握各类信息,成了人们日常生活、工作的重要一环,基本的电话业务已远远不能满足人们的要求。电话信息服务是当今信息时代不可缺少... 相似文献
7.
《世界电信》1997,(6)
什么是可视图文 可视图文(Videotex)是面向电话网上用户的交互式信息服务新业务,它是一种开放式的信息检索型系统,规定了一套统一的屏幕显示格式检索方法,还提供了一套公用通信系统,数据库一旦接入这个网络,它就可以向网上的所有用户提供服务;用户一旦接入此系统就可以获得网上所有数据库中的信息。可视图文的突出优点是用户使用简单,格式统一,可以实现信息资源共享。 在我国,由邮电部门经营、管理的可视图文业务是全国性信息服务系统。它利用中国公用分组交换数据网,把分布在全国各地的公用数据库和专用数据库组织起来,向用户提供检索型、交易型、计算和信息处理型业务,用户可以通过电话网使用可视图文业务。邮电部门经营的可 相似文献
8.
介绍了利用电话语音通讯卡,Sybase数据库及ODBC构建水情监测控制系统中的水情实时播报服务子系统的相关问题研究。 相似文献
9.
10.
11.
本文说明传统市内电话网使用通路交换的现状后 ,强调近年数据通信、Internet陆地移动通信和有线电视广播的急剧发展带来的冲击。建议市话网注意适应信息业务新形势 ,考虑市话网与分组数据网、Internet、蜂窝网和CATV等各种通信网的融合。 相似文献
12.
An overview of telecommunications services in the public switched telephone network (PSTN) and public switched packet data network (PSDN) in China is presented. Public telephone, data, telegraph, telematic, and future directory services provided by these networks are discussed 相似文献
13.
Supplementary services in the H.323 IP telephony network 总被引:2,自引:0,他引:2
Traditionally, different networks were developed to handle voice, data, and video. The circuit-switched telephone network carried voice and the packet network carried data. Due to different deployment of these networks, different services were developed, such as voice mail in the telephone network and electronic mail on the Internet. With the revolution of multimedia in the computer industry, voice, video, and data are now being carried on both networks. Supplementary services, such as transfer and forwarding (which were originally developed for private telephone networks and later migrated to public telephone networks) are now being developed for packet networks. The standards for packet networks are being defined in the H.323-based series of ITU-T recommendations. This article provides the H.323 architecture for supplementary services, the differences in deployment of these services between the circuit-switched and packet-switched networks, and interworking of these services across hybrid networks 相似文献
14.
ADSL: a new twisted-pair access to the information highway 总被引:3,自引:0,他引:3
The asymmetric digital subscriber line (ADSL) takes advantage of the existing twisted-pair copper loop that currently provides customer access to the telephone network. An ADSL modem is placed at each end of the loop to create a high speed access link above the existing telephone service. Since ADSL makes use of the existing copper telephone line, its application in the telephone network can conceivably be nearly as ubiquitous as the public telephone network itself. With ADSL, it is possible to connect small numbers of customers to broadband services in areas where full upgrade to hybrid fiber coaxial or fiber facilities is not economical in the near term. ADSL systems offer a means to introduce broadband services using the embedded base of metallic loops in areas where optic fiber-based, hybrid fiber-coaxial radio systems or other broadband transport systems may not be scheduled for deployment in time to meet business needs and customer demand. The article concentrates on ADSL systems capable of at least a nominal 6 Mb/s payload transport toward the customer, in addition to associated upstream channels and symmetrical “telephony” services via nonloaded loops that comply with carrier serving area design guidelines 相似文献
15.
Kiesling J.D. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1990,78(7):1107-1115
The general advantages and potential operating characteristics of the mobile satellite service (MSS) are described, and distinctions are made between radio telephone, which is interconnected to the public switched telephone network, and private mobile radio systems. Mobile satellite service offers voice, data, position location, and paging services, interconnection to the public switched telephone network, and the possibility of private networks. Performance and cost characteristics are given along with summaries of market needs and market demands. The space and ground systems of the MSS are described 相似文献
16.
Various aspects of transmission quality in evolving telephone services are reviewed and summarized from the customer's point of view. The evolution of the public switched telephone network is described. Quality specification methodology is examined, covering transmission standards, the room environment, and quality measures. Transmission quality in mixed analog and digital operation and in advanced telephone services are considered. Future telephone services are discussed 相似文献
17.
集成电路(IC)卡公用付费电话系统是继投币电话、磁卡电话之后适应我国公用电话业务发展需要的新一代公用电话设备。IC卡公用电话系统标准的制定,将对在我国公用电话业务中推广和使用IC卡电话新技术起到积极的指导和推动作用。 本文校为详细地阐述了IC卡、IC卡电话机及其管理系统标准的制定原则,以期有助于对新近颁布的有关标准的理解和实施。 相似文献
18.
The public telecommunication network of Turkey is briefly discussed in this paper. The existing telephone, telegraph, data, and other related services are summarized, and future trends in some of these services are indicated. These trends suggest that capital investments on the telecommunication services must be at least doubled in order that the standards in the country compete with those of the world averages. Finally, some of the research in communications is cited. 相似文献
19.
本文介绍了新建的北京电话号码查询系统,内容包括系统配置、工作流程以及排队机、查询数据库、管理系统和系统连接功能等特点,并介绍了系统可拓展的业务。 相似文献
20.
The Internet in Brazil is experiencing explosive growth. Spawned by a newsmedia-driven public interest which began in early 1994, this growth has taken unique paths. In a country where the entire data communications and telephone services infrastructure is under a state monopoly, Internet services to final users are scattered through hundreds of private providers of all sizes, while Internet backbones operated by transnational companies are being installed to compete with a state-funded backbone and a state-owned backbone. This article describes nongovernmental networking activity and how it evolved from a purely academic network to one serving a much larger public 相似文献