Use the optional SYSTEM keyword parameter in the CONSOLxx parmlib member to specify the system in the sysplex to which MVS™ should attempt to activate the console. This parameter will primarily refer to consoles that are physically attached to multiple systems and managed by a physical switch. In this case, the SYSTEM parameter determines which system should attempt to activate the console.
If SYSTEM is specified and the SYSTEM value names the current system being initialized, then MVS will activate the console device if the device is attached and in ready status. If the SYSTEM value names a system other than the one currently being initialized, then MVS will not activate the console even if it is attached and ready on the system being initialized. If SYSTEM is not specified, MVS activates the console on the first system to join the sysplex (to which the console is attached and ready).
It is possible that a device will not be ready (not turned on) when the system or sysplex is being initialized. The device might even be attached to another system as the sysplex is initialized (for example, during an error recovery situation). When you decide to use the device, first turn it on or re-attach it to the proper system, then issue a VARY CN,ONLINE command for the console.
During VARY CN,ONLINE command processing, the CONSOLE statement SYSTEM value is used to determine where to process the VARY CN,ONLINE command (unless the console was previously active or SYSTEM is specified on the VARY CN,ONLINE command).