&L0      &L0 = using normal dial-up lines.
          &L1 = using leased line.  You don't even need to dial
          to reach the other party because you have a private
          wire stretching between you.  Normally only wealthy
          corporations have leased lines.  When corporations use
          leased lines, they don't usually run dinky little 2400
          baud modems on them.