信息技术 系统间远程通信和信息交换 专用综合业务网 电路方式64kbit/s 承载服务 服务描述、功能能力和信息流

[中文适用范围]： 本国际标准规定了专用综合业务网络（PISN）支持的标准化电路模式承载服务的服务描述和控制方面，包括功能能力和信息流。 本国际标准包括以下基本服务： · 电路模式 64 kbit/s 无限制 8 kHz 结构化承载服务类别； · 可用于语音信息传输的电路模式64 kbit/s 8 kHz结构化承载服务类别； · 电路模式 64 kbit/s 8 kHz 结构化承载服务类别，可用于 3.1 kHz 音频信息传输。 PISN 应至少支持上述三种承载服务之一，以符合本国际标准。 本国际标准的范围不包括： · 呼叫建立时的服务协商， · 呼叫期间服务的改变，以及 · 单向服务。 本国际标准包括提供与以下公共 ISDN 补充服务等效的功能的可选程序：子地址和多用户号码。 注 1 – 补充业务和其他可与本国际标准规定的 64 kbit/s 电路交换承载业务结合使用的承载业务在其他标准中进行了处理。 注 2 – 服务规范基于本国际标准发布时可用的相应公共 ISDN 服务的信息。 注 3 – ITU-T 将子寻址和多用户号码视为补充服务。 注 4 — 对从公共 ISDN 呼入 PISN 的呼叫使用公共 ISDN 的直拨补充服务被视为 PISN 中基本服务的一部分。 注 5 – 使用公共 ISDN 的主叫线路识别显示和连接线路识别显示补充服务来获取来自或发往公共 ISDN 的呼叫的始发号码或连接号码被视为 PISN 中基本服务的一部分。 注 6 – 用户向网络提供（显式或隐式）其自己的号码（始发号码或连接号码）以及 PISN 向另一个网络提供始发号码或连接号码是一部分PISN 中基本服务的一部分，而不是主叫线路识别显示和连接线路识别显示补充服务的一部分。 这些补充服务仅涉及从网络到所服务的 PISN 用户的号码呈现。 [外文原描述]： This International Standard specifies the service description and control aspects, including functional capabilities and information flows, of standardised circuit-mode bearer services which may be supported by a Private Integrated Services Network (PISN). This International Standard includes the following basic services: _ Circuit-mode 64 kbit/s unrestricted 8 kHz structured bearer service category; _ Circuit-mode 64 kbit/s 8 kHz structured bearer service category usable for speech information transfer; _ Circuit-mode 64 kbit/s 8 kHz structured bearer service category usable for 3,1 kHz audio information transfer. A PISN shall support at least one of the above three bearer services to conform with this International Standard. The scope of this International Standard does not include: _ the negotiation of service at call establishment time, _ the change of service during a call, and _ unidirectional services. This International Standard includes optional procedures for the provision of functions equivalent to the following public ISDN supplementary services: Subaddress and Multiple Subscriber Number. NOTE 1 - Supplementary services and other bearer services which can be used in conjunction with 64 kbit/s circuit switched bearer services specified in this International Standard are dealt with in other standards. NOTE 2 - Service specifications are based on information concerning the corresponding public ISDN service available at the time of publication of this International Standard. NOTE 3 - ITU-T treat Subaddressing and Multiple Subscriber Number as supplementary services. NOTE 4 - The use of the Direct Dial In supplementary service of a public ISDN for calls incoming to a PISN from a public ISDN is regarded as part of the basic services in a PISN. NOTE 5 - The use of the Calling Line Identification Presentation and Connected Line Identification Presentation supplementary services of a public ISDN for obtaining the Originating Number or the Connected Number of a call from or to a public ISDN is regarded as part of the basic services in a PISN. NOTE 6 - The provision (either explicitly or implicitly) by the user to the network, of its own number (Originating Number or Connected Number), and the provision of an Originating Number or a Connected Number by a PISN to another network is a part of the basic services in a PISN and not a part of the Calling Line Identification Presentation and Connected Line Identification Presentation supplementary services. Those supplementary services are concerned only with the presentation of the number from the network to the served PISN user.