Siemens SIMATIC S7-1500 Function Manual page 319

Connection resources
11.3 Display of the connection resources
Display of the connection resources in STEP 7 (online view)
If you are connected to the CPU online, you can also see how many resources are currently
being used under "Connection information".
Figure 11-5 Connection resources - online
The online view of the "Connection resources" table in addition to the offline view also
contains columns with the connection resources currently being used. Thus, the online view
displays all used connection resources in the automation system, regardless of how the
connection was set up.
The "Other communication" row displays connection resources assigned for communication
with external devices. The table is updated automatically.
Note
If a routed S7 connection goes through a CPU, the required connection resources of the
CPU do not appear in the table of connection resources.
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Function Manual, 11/2019, A5E03735815-AH
Communication