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                                                                   Exhibit 4.(b)


                                                           Executed in 6 Parts
                                                         Counterpart No. (   )


                              NATIONAL EQUITY TRUST

                          LOW FIVE PORTFOLIO SERIES 217

                            REFERENCE TRUST AGREEMENT


          This Reference Trust Agreement dated July 5, 2000 among Prudential
Securities Incorporated, as Depositor and The Chase Manhattan Bank, as Trustee,
sets forth certain provisions in full and incorporates other provisions by
reference to the document entitled "National Equity Trust Low Five Portfolio
Series, Trust Indenture and Agreement" (the "Basic Agreement") dated April 25,
1995. Such provisions as are set forth in full herein and such provisions as are
incorporated by reference constitute a single instrument (the "Indenture").

                                WITNESSETH THAT:
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          In consideration of the premises and of the mutual agreements herein
contained, the Depositor and the Trustee agree as follows:

                                     Part I.
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                     STANDARD TERMS AND CONDITIONS OF TRUST


          Subject to the provisions of Part II hereof, all the provisions
contained in the Basic Agreement are herein incorporated by reference in their
entirety and shall be deemed to be a part of this instrument as fully and to the
same extent as though said provisions had been set forth in full in this
instrument except that the Basic Agreement is hereby amended in the following
manner:

          A.        Article I, entitled "Definitions", paragraph 22, shall be
                    amended as follows:

                    "Trustee shall mean The Chase Manhattan Bank or any
                    successor trustee appointed as hereinafter provided."

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          B.        Article II, entitled "Deposit of Securities; Acceptance of
                    Trust", shall be amended as follows:

                    The second sentence of Section 2.03 Issue of Units shall be
                    amended by deleting the words "on any day on which the
                    Depositor is the only Unit Holder."

          C.        Article III, entitled "Administration of Trust", shall be
                    amended as follows:

                    (i)       Section 3.01 Initial Costs shall be amended to
                              substitute the following language:

                              Section 3.01. Initial Cost The costs of organizing
                              the Trust and sale of the Trust Units shall, to
                              the extent of the expenses reimbursable to the
                              Depositor as provided below, be borne by the Unit
                              Holders, provided, however, that, to the extent
                              all of such costs are not borne by Unit Holders,
                              the amount of such costs not borne by Unit Holders
                              shall be borne by the Depositor and, provided
                              further, however, that the liability on the part
                              of the Depositor under this section shall not
                              include any fees or other expenses incurred in
                              connection with the administration of the Trust
                              subsequent to the deposit referred to in Section
                              2.01. Upon notification from the Depositor that
                              the primary offering period is concluded, the
                              Trustee shall withdraw from the Account or
                              Accounts specified in the Prospectus or, if no
                              Account is therein specified, from the Principal
                              Account, and pay to the Depositor the Depositor's
                              reimbursable expenses of organizing the Trust and
                              sale of the Trust Units in an amount certified to
                              the Trustee by the Depositor. If the balance of
                              the Principal Account is insufficient to make such
                              withdrawal, the Trustee shall, as directed by the
                              Depositor, sell Securities identified by the
                              Depositor, or distribute to the Depositor
                              Securities having a value, as determined under
                              Section 4.01 as of the date of distribution,
                              sufficient for such reimbursement. The
                              reimbursement provided for in this section shall
                              be for the account of the Unitholders of record at
                              the conclusion of the primary offering period and
                              shall not be reflected in the computation of the
                              Unit Value prior thereto. As used herein, the
                              Depositor's reimbursable expenses of organizing
                              the Trust and sale of the Trust Units shall
                              include the
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                              cost of the initial preparation and typesetting of
                              the registration statement, prospectuses
                              (including preliminary prospectuses), the
                              indenture, and other documents relating to the
                              Trust, SEC and state blue sky registration fees,
                              the cost of the initial valuation of the portfolio
                              and audit of the Trust, the initial fees and
                              expenses of the Trustee, and legal and other out-
                              of-pocket expenses related thereto, but not
                              including the expenses incurred in the printing of
                              preliminary prospectuses and prospectuses,
                              expenses incurred in the preparation and printing
                              of brochures and other advertising materials and
                              any other selling expenses. Any cash which the
                              Depositor has identified as to be used for
                              reimbursement of expenses pursuant to this Section
                              shall be reserved by the Trustee for such purpose
                              and shall not be subject to distribution or,
                              unless the Depositor otherwise directs, used for
                              payment of redemptions in excess of the per-Unit
                              amount allocable to Units tendered for redemption.
                              As directed by the Depositor, the Trustee will
                              advance funds to the Trust in an amount necessary
                              to reimburse the Depositor pursuant to this
                              Section and shall recover such advance from the
                              sale or sales of Securities at such time as the
                              Depositor shall direct, but in no event later than
                              the termination of the Trust. Repayment of any
                              such advance shall be secured by a lien on the
                              assets of the Trust prior to the interest of the
                              Unit Holders as provided in Section 6.04. (i)

                    (ii)      The third paragraph of Section 3.05 Distribution
                              shall be amended to add the following sentence at
                              the end thereof:

                              "The Trustee shall make a special distribution of
                              the cash balance in the Income and Principal
                              accounts available for such distribution to Unit
                              Holders of record on such dates as the Depositor
                              shall direct."

                    (iii)     The second to the last paragraph of Section 3.08
                              Sale of Securities shall be amended to replace the
                              word "equal" with the following phrase: "be
                              sufficient to pay."

                    (iv)      Section 3.14 Deferred Sales Charge shall be
                              amended to add the following sentences at the end
                              thereof:
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                              "References to Deferred Sales Charge in this Trust
                              Indenture and Agreement shall include any Creation
                              and Development Fee indicated in the prospectus
                              for a Trust. The Creation and Development Fee
                              shall be payable on each date so designated and in
                              an amount determined as specified in the
                              prospectus for a Trust."

          D.        Reference to United States Trust Company of New York in its
                    capacity as Trustee is replaced by the Chase Manhattan Bank
                    throughout the Basic Agreement.


          E.        Section 6.05 shall be amended to delete the clause "if the
                    Depositor shall determine in good faith that there has oc-
                    curred either (1) a material deterioration in the creditwor-
                    thiness of the Trustee or (2) one or more negligent acts on
                    the part of the Trustee having a materially adverse effect,
                    either singly or in the aggregate, on the Trust or on one or
                    more Trusts, such that the replacement of the Trustee is in
                    the best interest of the Unit Holders" and insert in place
                    thereof "upon the determination of the Depositor to remove
                    the Trustee for any reason, either with or without cause,
                    including but not limited to a determination by the Deposi-
                    tor that the Trustee has materially failed to perform its
                    duties under the Indenture and the interest of Unit Holders
                    has been substantially impaired as a result".

                                    Part II.
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                      SPECIAL TERMS AND CONDITIONS OF TRUST


          The following special terms and conditions are hereby agreed to:

          A. The Trust is denominated National Equity Trust, Low Five Portfolio
Series 217.

          B. The Units of the Trust shall be subject to a deferred sales charge.

          C. The contracts for the purchase of common stock listed in Schedule A
hereto are those which, subject to the terms of this Indenture, have been or are
to be deposited in Trust under this Indenture as of the date hereof.
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          D. The term "Depositor" shall mean Prudential Securities Incorporated.

          E. The aggregate number of Units referred to in Sections 2.03 and 9.01
of the Basic Agreement is 125,000 as of the date hereof.

          F. A Unit of the Trust is hereby declared initially equal to
1/125,000th of the Trust.

          G. The term "First Settlement Date" shall mean July 11, 2000.

          H. The terms "Computation Day" and "Record Date" shall mean quarterly
on the tenth day of September, December, March, and June commencing September
10, 2000.

          I. The term "Distribution Date" shall mean quarterly on the
twenty-fifth day of September, December, March, and June commencing September
25, 2000 or as soon thereafter as possible.

          J. The term "Termination Date" shall mean July 10, 2002.

          K. The Trustee's Annual Fee shall be $1.16 (per 1,000 Units) for
100,000,000 and above units outstanding; $1.22 (per 1,000 Units) for 50,000,000
- 99,999,999 units outstanding; $1.26 (per 1,000 Units) for 49,999,999 and below
units outstanding. In calculating the Trustee's annual fee, the fee applicable
to the number of units outstanding shall apply to all units outstanding.

          L. The Depositor's Portfolio supervisory service fee shall be $0.25
per 1,000 Units.

          [Signatures and acknowledgments on separate pages]
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          The Schedule of Portfolio Securities in Part A of the prospectus
          included in this Registration Statement for National Equity Trust, Low
          Five Portfolio Series 217 is hereby incorporated by reference herein
          as Schedule A hereto.