BS EN IEC 61158-6-23:2019 Industrial communication networks. Fieldbus specifications Application layer protocol specification. Type 23 elements

Packets (data transmission)
Coding (data conversion)
Process control
Data transmission
Application layer (OSI)
Fieldbus
Communication networks
Industrial
Open systems interconnection
Communication procedures
Bus networks
Automatic control systems
Computer networks
Interfaces (data processing)

Link: BS EN IEC 61158-6-23:2019 Industrial communication networks. Fieldbus specifications Application layer protocol specification. Type 23 elements
Source: BSI Standards