Notice of Maintenance Fees Payable

   Title 37 Code of Federal Regulations (CFR), Section 1.362(d) provides
that maintenance fees may be paid without surcharge for the six-month
period beginning 3, 7, and 11 years after the date of issue of patents
based on applications filed on or after Dec. 12, 1980. An additional
six-month grace period is provided by 35 U.S.C. 41(b) and 37 CFR 1.362(e)
for payment of the maintenance fee with the surcharge set forth in 37 CFR
1.20(h), as amended effective Dec. 16, 1991. If the maintenance fee is
not paid in the patent requiring such payment the patent will expire on
the 4th, 8th, or 12th anniversary of the grant.

   Attention is drawn to the patents which were issued on August 26, 1997
for which maintenance fees due at 3 years and six months may now be
paid. The patents have patent numbers within the following ranges:

        Utility Patents 5,659,895 through 5,661,848
        Reissue Patents base on the above identified patents.

   Attention is drawn to the patents which were issued on August 24, 1993
for which maintenance fees due at 7 years and six months may now be
paid. The patents have patent numbers within the following ranges:

        Utility Patents 5,237,702 through 5,239,702
        Reissue Patents based on the above identified patents.

   Attention is drawn to the patents which were issued on August 22, 1989
for which maintenance fees due at 11 years and six months may now be
paid. The patents have patent numbers within the following ranges:

        Utility Patents 4,858,245 through 4,860,380
        Reissue Patents based on the above identified patents.

   No maintenance fees are required for design or plant patents.

   Payments of maintenance fees in patents should be directed to
"Commissioner of Patents and Trademarks, Box M. Fee, Washington, D.C.
20231".
   For patents based on applications filed on or after Dec. 12,
1980, but before Aug. 27, 1982, patent owners must establish small
entity status according to 37 CFR 1.27 if they have not done so and if
they wish to pay the small entity amount.
   The current amounts of the maintenance fees due at 3 years and six
months, 7 years and six months, and 11 years and six months are set
forth in 37 CFR 1.20(e)-(g), as amended Oct. 1, 1997, which are
reproduced below:

37 CFR    1.20 Post-issuance fees

(e) For maintaining an original or reissue patent, except a design or
    plant patent, based on an application filed on or after after Dec.
    12, 1980, in force beyond 4 years; the fee is due by three years and
    six months after the original grant:

   By a small entity (   1.9(f))                               $470.00
   By other than a small entity                                $940.00

(f) For maintaining an original or reissue patent, except a design or
    plant patent, based on an application filed on or after Dec. 12, 1980
    in force beyond 8 years; the fee is due by seven years and six months
    after the original grant:

   By a small entity (   1.9(f))                               $950.00
   By other than a small entity                               $1900.00

(g) For maintaining an original or reissue patent, except a design or
    plant patent, based on an application filed on or after Dec. 12, 1980
    in force beyond 12 years; the fee is due by eleven years and six
    months after the original grant:

   By a small entity (   1.9(f))                              $1455.00
   By other than a small entity                               $2910.00

   The amount of the surcharges for paying the maintenance fee during the
grace period or after the expiration of the patent are set forth in 37
CFR 1.20(h), and (i) which are reproduced below:

(h) Surcharge for paying a maintenance fee during the 6 month grace
    period following the expiration of three years and six months, seven
    years and six months, and eleven years and six months after the date
    of the original grant of a patent based on an application filed on or
    after Dec. 12, 1980:

   By a small entity (   1.9(f))                                $65.00
   By other than a small entity                                $130.00

(i) Surcharge for accepting a maintenance fee after expiration of a
    patent for non-timely payment of a maintenance fee where the delay is
    shown to the satisfaction of the Commissioner to have been:

   (1) unavoidable                                             $700.00
   (2) unintentional                                         $1,640.00