Hardwired I/O is represented in the extended context diagram as information flows between the SUD and its external data sources and data sinks with labels using the syntax: <source>_2_<sink> (e.g. E_2_SUD, SUD_2_E in the Architectural System Approach: Hierarchy Level “0” (“Extended System Context”)) figure.
Note: At this stage it is not necessary to define the elements of the respective information flows. Instead, you can define them when the system behavior is captured (typically starting at hierarchy level 2).