PostMessage(Wnd, WM_KEYDOWN, vk_Return,  0 );
Application.ProcessMessages;
PostMessage(Wnd, WM_KEYUP, vk_Return,  0 );
Application.ProcessMessages;

PostMessage(Wnd, wm_Char, Word('а'),  0 );
Application.ProcessMessages;

procedure TForm1.Button1Click(Sender: TObject);
var Wnd: HWnd;
    ScanCodeKey, ScanCodeAlt: word;
    C: byte;
begin
   Wnd:= FindWindow('ConsoleWindowClass', nil);
   if IsIconic(Wnd) then ShowWindow(Wnd, SW_RESTORE)
                    else BringWindowToTop(Wnd);
   C:= Ord('X');
   ScanCodeKey:= MapVirtualKey(C,  0 );
   ScanCodeAlt:= MapVirtualKey(VK_MENU,  0 );
   Keybd_Event(VK_MENU, ScanCodeAlt,  0 ,  0 );
   Keybd_Event(C, ScanCodeKey,  0 ,  0 );
   Keybd_Event(C, ScanCodeKey, KEYEVENTF_KEYUP,  0 );
   Keybd_Event(VK_MENU, ScanCodeAlt, KEYEVENTF_KEYUP,  0 );
end;