SECURITIES AND EXCHANGE COMMISSION
                              Washington D.C. 20549





                                  SCHEDULE 13G
                    Under the Securities Exchange Act of 1934

                           (Amendment Number Eighteen)



                            Intelligent Systems Corp.
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                                (Name of Issuer)

                                     Common
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    45816D100
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                                 (Cusip Number)

                                   12/31/2006
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             (Date of Event Which Requires Filing of this Statement)



Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

         /X/  Rule 13d-1 (b)

         / / Rule 13d-1 (c)

         / / Rule 13d-1 (d)


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CUSIP NO. 45816D100                                                          13G


1) NAME OF REPORTING PERSON             I.R.S. NUMBER OF REPORTING PERSON
        Wallace R. Weitz & Company      Tax I.D. No. 47-0654095

2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
        (a) [ ]
        (b)  X

3) SEC USE ONLY

4) CITIZENSHIP OR PLACE OF ORGANIZATION State of Nebraska

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:
5) Sole Voting Power:               883,999
6) Shared Voting Power:             None
7) Sole Dispositive Power:          883,999
8) Shared Dispositive Power:        None

9) AGGREGATE AMOUNT OWNED BY EACH REPORTING PERSON
        883,999

10) CHECK IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES
        [ ]

11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9.
        19.7%

12) TYPE OF REPORTING PERSON
        IA


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CUSIP NO. 45816D100                                                          13G

1) NAME OF REPORTING PERSON
        Wallace R. Weitz

2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
        (a) [ ]
        (b)  X

2) SEC USE ONLY

3) CITIZENSHIP OR PLACE OF ORGANIZATION
        Citizen of the United States of America

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:
5)  Sole Voting Power:                      None
6)  Shared Voting Power:                    883,999
7)  Sole Dispositive Power:                 None
8)  Shared Dispositive Power:               883,999

9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
        883,999

10) CHECK IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES
        [ ]

11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
        19.7%

12) TYPE OF REPORTING PERSON
        IN


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Item 1(a). Name of Issuer:
               Intelligent Systems Corp.

Item 1(b). Address of Issuer's Principal Executive Office:
               4355 Shackleford Road
               Norcross, Georgia 30093

Item 2(a). Names of Persons Filing:
               Wallace R. Weitz & Company
               Wallace R. Weitz, President and Primary Owner of Wallace R.
               Weitz & Company

Item 2(b). Principal Business Address of Persons Filing:
               1125 South 103rd Street, Suite 600
               Omaha, Nebraska 68124-6008

Item 2(c). Citizenship:
               Wallace R. Weitz & Company - State of Nebraska
               Wallace R. Weitz - Citizen of United States of America

Item 2(d). Title of Class of Securities:
               Common Stock

Item 2(e). CUSIP Number:
               45816D100

Item 3. If this statement is filed pursuant to Rules 13d-1(b), or 13d-2(b),
check whether the person filing is a:

               (e)  Investment Adviser registered under Section 203 of the
                    Investment Advisers Act of 1940. This statement is being
                    filed by Wallace R. Weitz & Company ("Weitz & Co.") as a
                    registered investment adviser. All of the securities
                    reported in this statement are owned of record by investment
                    advisory clients of Weitz & Co. and none are owned directly
                    or indirectly by Weitz & Co. As permitted by Rule 13d-4, the
                    filing of this statement shall not be construed as an
                    admission that Weitz & Co. is the beneficial owner of any of
                    the securities covered by the statement.

               (g)  Control Person. This statement is also being filed by
                    Wallace R. Weitz ("Weitz"), President and primary owner of
                    Weitz & Co. in the event he could be deemed to be an
                    indirect beneficial owner of the securities reported by
                    Weitz & Co. through the exercise of voting control and/or
                    dispositive power over the securities as a result of his
                    official positions or ownership of the voting securities of
                    Weitz & Co. Mr. Weitz does not own directly or indirectly
                    any securities covered by this statement for his own
                    account. As permitted by Rule 13d-4, the filing of this
                    statement shall not be construed as an admission that Mr.
                    Weitz is the beneficial owner of any of the securities
                    covered by this statement.


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Item 4. Ownership:
                        (a) Amount Beneficially Owned:
                              (i)  Weitz & Co.   883,999 Shares
                              (ii) Weitz         883,999 Shares

                        (b) Percent of Class:
                              (i)  Weitz & Co.   19.7%
                              (ii) Weitz         19.7%

                        (c) Number of Shares as to which such person has:
                              (I)   sole power to direct vote:
                                    (i)  Weitz & Co.     883,999
                                    (ii) Weitz                 0

                              (II)  shared power to direct vote:
                                    (i)  Weitz & Co.     883,999
                                    (ii) Weitz           883,999

                              (III) sole power to dispose:
                                    (i)  Weitz & Co.     883,999
                                    (ii) Weitz                 0

                              (IV)  shared power to dispose:
                                    (i)  Weitz & Co.     883,999
                                    (ii) Weitz           883,999

Item 5. Ownership of Five Percent or Less of a Class
               N/A

Item 6. Ownership of More Than Five Percent on Behalf of Another Person
               The Weitz Funds-Partners III Opportunity Fund, a registered
               investment company, is the record owner of 883,999 shares of the
               Issuer as of December 31, 2006, representing 19.7% of the
               Issuer's shares. Weitz & Co. has the sole power to vote or direct
               the vote of the securities owned by Partners III Opportunity
               Fund.

Item 7. Identification and Classification of the Subsidiary Which Acquired the
Security Being Reported on By the Parent Holding Company
               N/A

Item 8. Identification and Classification of Members of the Group
               N/A

Item 9. Notice of Dissolution of Group
               N/A


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Item 10. Certification
         By signing below I certify that, to the best of my knowledge and
         belief, the securities referred to above were acquired in the ordinary
         course of business and were not acquired for the purpose of and do not
         have the effect of changing or influencing the control of the issuer of
         such securities and were not acquired in connection with or as a
         participant in any transaction having such purposes or effect.

         After reasonable inquiry and to the best of my knowledge and belief, I
         certify that the information set forth in this statement is true,
         complete and correct.

         Date:  January 18, 2007

         WALLACE R. WEITZ & COMPANY

         By:      /s/ Wallace R. Weitz
         Name:    Wallace R. Weitz
         Title:   President

         WALLACE R. WEITZ
         (Individually)

         /s/ Wallace R. Weitz

                             Joint Filing Agreement

In accordance with Rule 13d-1 (k) under the Securities Exchange Act of 1934, the
persons or entities named below agree to the joint filing on behalf of each of
them of this Schedule 13G with respect to the securities of the Issuer and
further agree that this joint filing agreement be included as an exhibit to this
Schedule 13G. In evidence thereof, the undersigned hereby execute this agreement
as of the 18th day of January, 2007.

         WALLACE R. WEITZ & COMPANY

         By:     /s/ Wallace R. Weitz
         Name:   Wallace R. Weitz
         Title:  President

         WALLACE R. WEITZ
         (Individually)

         /s/ Wallace R. Weitz


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