*^C			! Return from program session to EXEC
  ^C			! (only single ^C will echo).

  @PUSH			! Start child EXEC instance.

   TOPS-20 Command processor 7(4168)-1
  @MM                   ! Start a program in the child EXEC.

  ...			! Use program then exit.

  @POP			! Terminate child EXEC and return to
  			! parent EXEC.

  @CONTINUE(3)		! Return to original program session.
  *			! Depending on the program you may
  			! continue entering commands or
  			! refresh the display.