Cdn $48,633.85                                                    March 19, 1998



                                 PROMISSORY NOTE



FOR VALUE RECEIVED,  the undersigned  ("Maker")  promises to pay to the order of
Sonus  Corp.,  an  Alberta,  Canada  corporation  (hereinafter  referred  to  as
"Holder"),  the principal sum of Forty-Eight  Thousand Six Hundred  Thirty-Three
and 85/100 Canadian  Dollars (Cdn  $48,633.85) with interest thereon at the rate
of seven and  three-quarters  percent (7.75%) per annum.  Principal and interest
shall be payable in lawful money of the United States of America at 111 SW Fifth
Avenue, Suite 2390, Portland,  Oregon 97204 or at such other place as Holder may
designate in writing.  Principal  and  interest  shall become due and payable on
December 31, 2000.

Maker agrees to pay all costs of collection  of any amounts due  hereunder  when
incurred, including, without limitation, attorney's fees and expenses, including
on any  appeal.  Such  costs  shall be added to the  balance  of  principal  and
interest then due.

Maker,  for himself and his successors and assigns,  hereby waives  presentment,
demand,  notice and protest and any defense by reason of  extension  of time for
payment or other  indulgences.  Failure of the Holder to assert any right herein
shall not be deemed to be waiver hereof.

This Note is secured.  Maker has executed a Pledge  Agreement that describes the
collateral  and the process for  realization  on the  security in the event of a
default hereunder.

This  Promissory  Note  shall be  governed  by and  construed  and  enforced  in
accordance with the laws of the State of Oregon.

                                     Maker:



                                     /s/ Brandon M. Dawson
                                     Brandon M. Dawson, an individual
<PAGE>
                                PLEDGE AGREEMENT


DATE:                          May 1, 1998

PARTIES:                       SONUS CORP., an Alberta,     ("Lender")
                               Canada corporation

AND:                           BRANDON M. DAWSON, an individual   ("Borrower")


RECITAL:

Borrower has issued to Lender the following promissory notes (the "Notes"):

                  Date                               Amount
                  ----                               ------

                  5-8-97                             US $67,500
                  12-26-97                           Cdn $43,985.01
                  3-19-98                            Cdn $48,633.85
                  4-24-98                            US $91,000

To secure all amounts due now or later from  Borrower to Lender under the Notes,
Borrower  hereby  grants  and  pledges  to  Lender a  security  interest  in the
following described property:

         Sixty  Thousand  (60,000)  shares  of the  common  stock of  Lender  as
         evidenced by stock  certificate  no.  ------- ,  accompanied by a stock
         power duly executed in blank by Borrower (the "Shares").

AGREEMENT:

SECTION 1.  POSSESSION

Lender shall retain possession of the Shares until all amounts due from Borrower
to Lender under the Notes are paid in full.

SECTION 2.  DEFAULT

Borrower  shall be in default under this Agreement if Borrower fails to make any
payment to Lender when due, or if borrower  violates any terms of this Agreement
or the Notes. Upon default,  Lender shall have all the rights of a secured party
under the Oregon

<PAGE>

Uniform Commercial Code, including,  subject to Section 3, the right to sell the
Shares at either a private or public sale.

SECTION 3.  SECURITIES LAWS

Borrower  acknowledges  that the sale of the  Shares by Lender may be subject to
certain  securities  laws,  and Borrower  agrees that Lender may take any action
necessary  in order to comply with such laws,  including  any and all  necessary
restrictions with respect to the time, place, manner and conditions of sale.

IN WITNESS  WHEREOF,  Borrower has executed this Pledge Agreement on the day and
year first written above.

                                        Borrower:



                                        /s/ Brandon M. Dawson
                                        Brandon M. Dawson
                                        an individual



                                        Lender:

                                        Sonus Corp.

                                        By: /s/ Edwin J. Kawasaki
                                              Edwin J. Kawasaki
                                              Vice President-Finance