scope:

This part of ISO 20794 describes the CXPI data link layer and the CXPI physical layer. The CXPI data link layer (DLL) requirements are composed of - DLL protocol entity requirements; - DLL device interface requirements; and - DLL network system requirements. The DLL covers the - mapping of CXPI parameters between DLL and higher OSI layers; - transmission processing; - reception processing; - arbitration processing; - frame structure; - error detection; and - error indication. The CXPI physical layer (PHY) comprises of the physical signalling (PS) sub-layer, which is implemented in the CXPI protocol or the CXPI transceiver or the CXPI System Base Chip (SBC). It also comprises of the physical media attachment (PMA) sub-layer, which is implemented normally in the CXPI transceiver or the CXPI SBC, which also may implement additional protection circuitry, not in scope of this document. The CXPI PHY also comprises of the physical media dependent (PMD) sub-layer, which includes cable, and the termination resistors.