EXHIBIT 4.1


Frank A. Ciccotto, Jr.
Managing Director
E-Business Services
55 Water Street, 45th Floor
New York, NY  10041
Tel. 212-438-4417
Fax 212-438-7748
frank_ciccotto@
standardandpoors.com                                 STANDARD & POOR'S
                                         A Division of The McGraw Hill Companies


                                   May 1, 2008


Van Kampen Funds Inc.
522 Fifth  Avenue
New York, New York  10036

The Bank of New York
Unit Investment Trust Dept.
2 Hanson Place, 12th Floor
Brooklyn, New York 11217


                Re: Van Kampen Unit Trusts, Municipal Series 689

               Ohio Investors' Quality Tax-Exempt Trust, Series 17

Gentlemen:

     We have examined Registration Statement File No. 333-149154 for the above
mentioned trust. We hereby acknowledge that Standard & Poor's Securities
Evaluations, Inc. is currently acting as the evaluator for the trust. We hereby
consent to the use in the Registration Statement of the references to Standard &
Poor's Securities Evaluations, Inc., as evaluator.

     In addition, we hereby confirm that the ratings indicated in the
Registration Statement for the respective bonds comprising the trust portfolio
are the ratings indicated in our KENNYBASE database as of the date of the
evaluation report.

     You are hereby authorized to a file a copy of this letter with the
Securities and Exchange Commission.

                                                              Sincerely,

                                                              Frank A Ciccotto
                                                              Vice President