GB/T 17801-1999 in English

《GB/T 17801-1999经公用交换电话网或综合业务数字网或电路交换公用数据网接入分组交换公用数据网的分组式数据终端设备（DTE）和数据电路终接设备（DCE）之间的接口》由339-2（工业和信息化部（通信））归口，主管部门为工业和信息化部（通信）。
本标准为X.1建议中定义的分组式用户业务的DTE规定了DTE/DCE接口功能和规程，以便使这种DTE经公用交换网接入PSPDN。在本标准中，公用交换网（PSN）是指公用交换电话网（PSTN）或提供电路交换承载业务的综合业务数字网（ISDN）或电路交换公用数据网（CSPDN）。注：透明电路连接的ISDN接口技术要求在X.31建议中予以说明。在本标准中，只考虑通过ISDN接入PSPDN业务的DTE功能。

Scope

This standard specifies the DTE/DCE interface functions and procedures for the DTE defined by X.1 for packet-based user services, so that this DTE can access the PSPDN via the public switching network. In this standard, Public Switched Network (PSN) refers to the Public Switched Telephone Network (PSTN) or the Integrated Services Digital Network (ISDN) or the Circuit Switched Public Data Circle (CSPDN) that provides circuit switched bearer services. Note: The technical requirements of the ISDN interface for transparent circuit connection are specified in Recommendation X.31. In this standard, only consider the DTE function of accessing PSPDN business through ISDN. In the case of PSTN, the DTE/DCE interface of X.32 is consistent with the interface between the DTE and the modem; in the case of ISDN, the X.32 interface is the same as the R reference point (see Figure 1); in the case of CSPDN Next, the X.32DTE/DCE interface is consistent with the X.21 or X.21bis interface. This applies regardless of whether the administration provides the DCE or not, regardless of how the interface is physically implemented (for example, whether the DTE and the DCE are installed in the same enclosure), and in either case the PSN only concerns; Access; Provides the transmission medium Optionally, a PSN number for identification and addressing. Administrations may provide one or more of the following physical layer interfaces: For access via CSPDN, the X.21 or X.21bis recommendations described in 4.1 or 4.2 may be used; for access via PSTN , the corresponding V series recommendations described in 4.3 can be used; for access through ISDN, refer to X.31 recommendations. See Chapter 4 of this standard for the correct use of these suggested points. Transmission facilities are duplex or (or use) half duplex. 5.6 of this standard specifies the specific procedures for operating on half-duplex transmission facilities. In the link layer, the LAPB link access procedure recommended by X.25 is used on a single switched physical circuit. The format and procedures of LAPB shall comply with 2.2, 2.3 and 2.4 of Recommendation X.25 and the additional provisions in Chapter 5 of this standard. The format and procedures of the packet layer comply with Chapters 3, 4, 5, 6 and 7 of the X.25 recommendation and the additional provisions in Chapter 6 of this standard. Note: In the case of using TE1 terminal, the functions of DTE and TA can be implemented in the same device. In this case, this standard deals with the operation of layers 2 and 3 in the B-channel. The S reference point procedure is described in Recommendation X.31.