Applications running from the shell can switch to TSO/3270 pass-through mode, which lets an application invoke TSO/E functions. For application development purposes, you can specify a key that ends TSO/3270 pass-through mode and forces OMVS to return to the shell session.

Because this key is used only during application development, the default is ENDPASSTHROUGH(NO).

For more information about TSO/3270 pass-through mode, see Appendix A. TSO/3270 pass-through Mode in z/OS UNIX System Services Programming Tools.