BS EN IEC 61158-6-12:2019 Industrial communication networks. Fieldbus specifications Application layer protocol specification. Type 12 elements

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

Link: BS EN IEC 61158-6-12:2019 Industrial communication networks. Fieldbus specifications Application layer protocol specification. Type 12 elements
Source: BSI Standards