GB/T 16966-1997 in English

《GB/T 16966-1997信息技术 连接到综合业务数字网（ISDN）的包式终端设备提供OSI连接方式网络服务》由TC28（全国信息技术标准化技术委员会）归口，TC28SC6（全国信息技术标准化技术委员会数据通信分会）执行，主管部门为国家标准化管理委员会。
本标准论述了使用CCITTX.25中描述的虚呼叫来提供CONS，而不涉及X.25永久虚电路的使用。

Scope

According to the regulations described in CCITTX.31, this standard stipulates the method of providing OSI connection mode network service (CONS) for the packet-type terminal equipment connected to the integrated services digital network (ISDN). This method is defined by specifying the mutual mapping between CONS primitives and parameters and protocol elements used by the following two types of packetized terminal equipment: a) X.25DTE (TE2) connected to the R reference point and accessing ISDN; and b) Packet ISDN Terminal (TE1) running the GB/T BBBB Packet Protocol (PLP) and connected to ISDN at the S or T reference point. This standard applies to the following two situations: a) When operating in accordance with CCITT X.31, a TE1 or TE2 is connected to an ISDN packet processor or an access unit of a packet-switched data network arriving via ISDN; b) Using ISDN circuit switching channel, TE1 and (or) TE2/TA are directly connected to each other (that is, the terminal operates in DTE/DTE mode). This standard does not involve using TA on R reference point to access TE2 when ISDN circuit switching channel is used and the terminal operates in DTE/DTE mode (see CCITTX.613 or ISO/IEC10588). Note 1 TE1, TE2 and TA equipment and K, S and T reference points are defined in CCITT1.411. 2 This standard applies to IE1 or TE2/TAI (ie an OSI end system), whether it is a physically independent system or embedded in other systems such as PBX. This standard discusses the use of virtual calls described in CCIT TX.25 to provide CONS, and does not refer to the use of X.25 permanent virtual circuits. The extension of this standard to include the use of X.25PVC is for further study. NOTE: This standard uses numbers rather than names to identify layers. This is done to align the terminology of the standard with the terminology of the relevant ISDN recommendations and does not imply that the functionality of the layers differs from that specified in the OSI reference model