对于支持CONS的协议，CONS的抽象原语和参数与协议的真实元素之间必须存在映射。对于X.25数据包层协议（PLP），本标准的主体使用虚拟呼叫为X.25/PLP-1984提供了这种映射。还提供了CONS原语和参数到X.25/PLP-1980和SNDCP的映射。这些映射适用于X.25 VC服务。指定描述三类实现的两组过程。

For a protocol to support the CONS, there must be a mapping between the abstract primitives and parameters of the CONS and the real elements of the protocol. For the X.25 Packet Layer Protocol (PLP), the main body of this standard provides such a mapping for the X.25/PLP-1984 using Virtual Calls. Also provides a mapping of the CONS primitives and parameters to the X.25/PLP-1980 plus an SNDCP. These mappings apply to the X.25 VC service. Specifies two sets of procedures from which three classes of implementation are described.