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           SECURED REVOLVING LINE OF CREDIT APPLICATION AND AGREEMENT

                                       ("AGREEMENT")

Name of Applicant:    ILLUMINET, INC.
                      a Delaware corporation ("Applicant")

Address:       4501 Intelco Loop, S.E.
               Olympia, WA 98507

Applicant hereby applies to Rural Telephone Finance Cooperative ("RTFC"), a
South Dakota cooperative association, for a revolving line of credit loan in an
amount not to exceed seven million three hundred thousand ($7,300,000).
Applicant hereby agrees that in the event RTFC approves this Agreement, the
terms and conditions herein and any additional terms and conditions as approved
by RTFC, and as agreed to in writing by Applicant, shall constitute a valid and
binding agreement between Applicant and RTFC. In consideration of their mutual
promises hereunder and other valuable consideration, the receipt and sufficiency
of which is hereby acknowledged, RTFC and Applicant agree to the following terms
and conditions:

1.      REVOLVING CREDIT AND TERM. Upon approval of this Agreement, RTFC agrees
        to make advances to the Applicant pursuant to the terms of this
        Agreement ("Advances") in the maximum amount specified above or such
        lesser amount as may be approved by RTFC in accordance with the terms
        and conditions hereof. Within such limits, the Applicant may borrow,
        repay and reborrow at any time or from time to time for a period up to
        sixty (60) months from the Effective Date (as defined herein) (the
        "Maturity Date").

2.      REQUISITIONS. The Applicant shall give RTFC such prior notice of
        requests for Advances as RTFC may reasonably require from time to time.

3.      INTEREST RATE AND PAYMENT. The Applicant unconditionally promises and
        agrees to pay, as and when due, interest on all amounts advanced
        hereunder from the date of each Advance and to repay all amounts
        advanced hereunder with interest on the Maturity Date. Interest shall be
        due and payable quarterly on the first day of each January, April, July
        and October, commencing on the first such date after such initial
        Advance; except that if RTFC gives notice thereof to the Applicant
        before the first day of any month, interest shall thereafter be due and
        payable on the 15th day of such month and each month thereafter. RTFC
        shall invoice the Applicant at least five days prior to the due date of
        any such interest payment. All amounts shall be payable at RTFC's main
        office at Woodland Park, 2201 Cooperative Way, Herndon, Virginia
        20171-3025 or at such other location as designated by RTFC from time to
        time.

        The interest rate on all Advances will be equal to the Prevailing Bank
        Prime Rate (as defined herein), plus one and one-half percent per annum
        or such lesser total rate per annum as may be fixed by RTFC from time to
        time. Interest will be computed on the basis of a year of 365 days. The
        interest rate will be adjusted as determined from time to time by RTFC,
        provided that no such adjustment may be effective on a date other than



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        the first or sixteenth day of any month, and will remain in effect until
        a subsequent change in rate occurs.

        The "Prevailing Bank Prime Rate" is that bank prime rate published in
        the "Money Rates" column of any edition of The Wall Street Journal which
        RTFC determines in its discretion to be the representative bank prime
        rate on the day preceding the day on which an adjustment in the interest
        rate hereof shall become effective. If such preceding day is not a
        publication day for The Wall Street Journal then the Prevailing Bank
        Prime Rate shall be established by reference to such "Money Rates"
        column as of the last publication day next preceding the day on which
        such adjustment shall become effective; provided if The Wall Street
        Journal shall cease to be published, then the Prevailing Bank Prime Rate
        shall be determined by RTFC, by reference to another publication
        reporting bank prime rates in a similar manner.

4.      RTFC ACCOUNTS. RTFC shall maintain in accordance with its usual practice
        an account or accounts evidencing the indebtedness of the Applicant
        resulting from each Advance made from - time to time and the amounts of
        principal and interest payable and paid from time to time hereunder. In
        any legal action or proceeding in respect of this Agreement, the entries
        made in such account or accounts (whether stored on computer memory,
        microfilm, invoices or otherwise) shall be presumptive evidence (absent
        manifest error) of the existence and amounts of the Applicant's
        transactions therein recorded.

5.      CORPORATE AND REGULATORY APPROVALS. Applicant represents that it has
        obtained any and all necessary corporate and regulatory approvals for
        Applicant to execute and perform pursuant to this Agreement.

6.      REPORTS. Applicant agrees to deliver to RTFC, promptly upon their
        becoming available, a copy of (i) any annual report prepared subsequent
        to the submission of this Agreement; (ii) its monthly operating report
        within twenty (20) days for any month in which there are advances
        outstanding pursuant to this Agreement; and (iii) any other reports
        which RTFC reasonably requests during the term of this Agreement.

7.      FEES. If any amount outstanding and due hereunder shall not be paid when
        due, Applicant agrees to pay on demand RTFC's reasonable costs of
        collection or enforcement of this Agreement, or preparation therefor,
        including reasonable fees of counsel. If payment of any principal and/or
        interest due under the terms of this Agreement is not received at RTFC's
        office in Herndon, Virginia, or such other location designated by RTFC
        within five (5) business days after the due date thereof (such unpaid
        amount of principal and/or interest being herein called the "delinquent
        amount," and the period beginning after such due date being herein
        called the "late-payment period"), Applicant will pay to RTFC, on
        demand, in addition to all other amounts due under the terms of this
        Agreement, any late-payment charge as may then be in effect pursuant to
        RTFC's policy on the delinquent amount for the late payment period.

8.      LIMITATION ON ADVANCES. The amount of outstanding Advances hereunder in
        any single calendar year may not at any one time exceed the amount
        approved by RTFC.



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9.      REDUCE BALANCE TO ZERO. In the event this Agreement is for a term of
        more than 12 months, then within 360 days of the first Advance,
        Applicant will reduce to zero for a period of at least five consecutive
        business days, (the last day of such five day period being herein called
        the "Zero Balance Date") amounts outstanding hereunder, and will reduce
        to zero for a period of at least five consecutive business days (the
        last day of such five business day period being called the "Subsequent
        Zero Balance Date") amounts outstanding hereunder within 360 days from
        the Zero Balance Date or Subsequent Zero Balance Date, as appropriate.

10.     CREDIT SUPPORT. This Agreement may not be used as credit support for any
        other financings without RTFC's prior written approval.

11.     NOTICES, ACCELERATION OF DEBT AND WAIVERS. While any amount hereunder is
        outstanding, Applicant agrees to notify RTFC of any delinquency or
        default on any of its financial obligations, any material adverse change
        in its financial or business condition and if any representation or
        warranty made in this Agreement has become untrue in any respect having
        a material adverse effect on the financial condition or business of the
        Applicant. If any delinquency, default, or any other event as a result
        of which any holder of indebtedness may declare the same due and payable
        shall occur and continue for more than any applicable grace period, or
        any representation or warranty herein shall become untrue in any
        material respect, or Applicant shall fail to comply with any term of
        this Agreement, or if the financial condition of Applicant shall have
        changed to the extent that such change, in the reasonable judgment of
        RTFC, materially increases RTFC's risk hereunder, then RTFC may declare
        at any time all outstanding amounts hereunder immediately due and
        payable in full with accrued interest, without presentment or demand,
        and may withhold advances of funds. The Applicant waives the defense of
        usury and all rights to setoff, counterclaim, deduction or recoupment.

12.     PURPOSE, REPAYMENTS AND DEPOSIT. Applicant agrees that any and all
        Advances hereunder will be used only for proper corporate purposes and
        consistently with the requirements of outstanding security documents of
        Applicant relating to its operations. Applicant agrees that this loan
        shall be repayable out of Applicant's general funds and that loan
        proceeds will not be deposited in Applicant's Trustee-Special
        Construction Fund Account or any other account dedicated for secured
        financing advances.

13.     ADDITIONAL INDEBTEDNESS. While any amount hereunder is outstanding and
        unless otherwise disclosed in writing to RTFC, Applicant agrees that it
        will not, without prior written consent of RTFC, create, incur, assume,
        guarantee or otherwise become obligated for any additional indebtedness,
        other than to RTFC except that the Applicant may borrow against another
        loan previously approved by RTFC.

14.     SURVIVAL OF REPRESENTATIONS, WARRANTIES AND PAYMENT OBLIGATIONS.
        Applicant agrees that the representations and warranties made in this
        Agreement shall survive the making of Advances hereunder. Any
        unsatisfied payment obligation hereunder shall survive the maturity and
        cancellation of this Agreement.



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15.     REPRESENTATIONS AND WARRANTIES. Except as set forth in writing and
        attached hereto, Applicant represents and warrants as of the date of its
        application and on the date of each and every Advance hereunder that:

        (a)     The Applicant has and will meet all material obligations and be
                in material compliance with all instruments under which it is
                bound and that all information submitted in support of its
                application is true, complete and correct in all material
                respects;

        (b)     There has been no material adverse change in the Applicant's
                business or financial condition from that set forth in its
                audited financial statements;

        (c)     The Applicant has no outstanding loans from sources other than
                RTFC;

        (d)     The Applicant is not in default in any material respect of any
                of its obligations and no litigation is threatened or pending
                which would have a material adverse impact on the Applicant's
                ability to perform under this Agreement; and

        (e)     The Applicant has no lines of credit with any other lenders.

16.     SUBMISSIONS. Applicant submits the following documents in support of
        this Agreement (if not previously received by RTFC):

        (a)     The most recently prepared income statement and balance sheet
                and all attachments thereto; and

        (b)     The income statement and balance sheet for each of the three
                preceding calendar years; and

        (c)     Applicant's most recent annual audit report prepared by an
                independent certified public accountant.

17.     CONSENT TO PATRONAGE CAPITAL DISTRIBUTIONS. Applicant hereby consents
        that the amount of any distributions with respect to Applicant's
        patronage which are made in written notices of allocation (as defined in
        Section 1388 of the Internal Revenue Code of 1986, as amended ("Code")
        including any other comparable successor provision) and which are
        received from RTFC will be taken into account by Applicant at their
        stated dollar amounts in the manner provided in Section 1385(a) of the
        Code in the taxable year in which such written notices of allocation are
        received.

18.     GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY AND BE CONSTRUED IN
        ACCORDANCE WITH THE LAWS OF THE COMMONWEALTH OF VIRGINIA.

19.     SEVERABILITY. If any term, provision or condition, or any part thereof,
        of this Agreement shall for any reason be found or held invalid or
        unenforceable by any court or governmental agency of competent
        jurisdiction, such invalidity or unenforceability shall not affect the
        remainder of such term, provision or condition nor any other term,



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        provision or condition, and this Agreement shall survive and be
        construed as if such invalid or unenforceable term, provision or
        condition had not been contained therein.

20.     SETOFF. RTFC is hereby authorized at any time and from time to time
        without prior notice to the Applicant to exercise rights of setoff or
        recoupment and apply any and all amounts held, or hereafter held, by
        RTFC or owed to the Applicant or for the credit or account of the
        Applicant against any and all of the obligations of the Applicant now or
        hereafter existing hereunder. RTFC agrees to notify the Applicant
        promptly after any such setoff or recoupment and the application
        thereof, provided that the failure to give such notice shall not affect
        the validity of such setoff, recoupment or application. The rights of
        RTFC under this section are in addition to any other rights and remedies
        (including other rights of setoff or recoupment) which RTFC may have.

21.     ADDITIONAL TERMS AND CONDITIONS. Additional terms and conditions set
        forth herein or attached hereto are an integral part of this Agreement.

22.     TERMINATION AND CANCELLATION OF EXISTING AGREEMENT. Applicant agrees to
        the termination and cancellation of its existing revolving line of
        credit with RTFC (#WA 812-S-01 & WA 800-S-01), if any, on the Effective
        Date, in consideration of RTFC's approval of this Agreement, provided,
        however, Applicant agrees that any unsatisfied payment obligation owed
        pursuant to such lines of credit shall survive their termination and
        cancellation.

23.     INTEGRATION. This Agreement and the matters incorporated by reference
        contain the entire agreement of the parties hereto with respect to the
        matters covered and the transactions contemplated hereby, and no other
        agreement, statement or promise made by any party hereto, or by any
        employee, officer, agent or attorney of any party hereto, which is not
        contained herein, shall be valid and binding. No amendment or waiver to
        this Agreement shall be valid and binding except if in writing and
        signed by both parties.

24.     HEADINGS. The headings and sub-headings contained in this Agreement are
        intended to be used for convenience only and do not constitute part of
        this Agreement.



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(For RTFC Use Only)

                         ADDITIONAL TERMS AND CONDITIONS

1.      All advances hereunder shall be secured pursuant to the Consolidated
        Mortgage and Security Agreement by and between Applicant and RTFC dated
        as of even date herewith. ("Mortgage") and the obligation of Applicant
        to repay Advances hereunder shall be deemed an "Additional Note" secured
        by the Mortgage.

2.      The total principal balance outstanding on this secured line of credit
        shall not exceed the lesser of 80% of the value of Borrower's prevailing
        accounts receivable of $7,300,000.

3.      Each request for advance from this line of credit must be submitted to
        RTFC in writing and accompanied by:

        (a)     The most recent balance sheet and income statement;

        (b)     A monthly cash flow forecast, in form and content satisfactory
                to RTFC, indicating all planned advances from and repayment of
                the line of credit, including the current advance request; and

        (c)     A collateral position statement, in a form and content
                satisfactory to RTFC, itemizing all of Applicant's outstanding
                secured debt and the corresponding net book value of the
                collateral for said indebtedness.



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Name of Applicant:    ILLUMINET, INC

Signed By:
          ----------------------------------------------------------------------
Title:
      --------------------------------------------------------------------------
Date of Application:
                    ------------------------------------------------------------

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                              APPROVAL OF AGREEMENT

This Agreement is approved, subject to any Additional Terms and Conditions noted
above, on the date set forth below and is effective as of _________________,
199__ (the "Effective Date").

                       RURAL TELEPHONE FINANCE COOPERATIVE

Signed By: ____________________________________________, Chief Executive Officer

Loan: # WA 812-S-01                     Date of Approval:
                                                         -----------------------




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Name of Applicant:    ILLUMINET, INC

Signed By:
          ----------------------------------------------------------------------
Title:
      --------------------------------------------------------------------------
Date of Application:
                    ------------------------------------------------------------

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                              APPROVAL OF AGREEMENT

This Agreement is approved, subject to any Additional Terms and Conditions noted
above, on the date set forth below and is effective as of _________________,
199__ (the "Effective Date").

                       RURAL TELEPHONE FINANCE COOPERATIVE

Signed By: ____________________________________________, Chief Executive Officer

Loan: # WA 812-S-01                     Date of Approval:
                                                         -----------------------