Defaults

   o  If you enter the .TAB STOPS command without number or comma
      specifications, the use of all tab stops is suspended and the
      tab character is equivalent to a space.

   o  If you do not enter the .TAB STOPS command, successive tab
      characters work as if you had set a tab stop every eight
      positions; that is, as if you had entered .TAB STOPS 8,16,24,
      and so on. Note that because .PAGE SIZE has a width limit of
      150, 149 is the practical limit for .TAB STOPS.