If the systems are connected through VTAM, Control‑O uses the IOA Gateway to transfer action requests to the specified system, and waits for the response if necessary (assuming the WAITRESP subparameter is set to Y in the DO COMMAND statement).

For systems linked by XCF Services:

If the systems are members of a Sysplex environment, Control‑O directs actions to be performed on other systems using the SYSTEM subparameter or by the %%$COMMSYS system variable in the following statements:

• DO COMMAND and DO DISPLAY

  The actions are routed using the existing XCF connection created by MVS for MCS support.

• DO RULE

  The actions are routed using a Control‑O-created XCF group.