UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                  SCHEDULE 13G


                    Under the Securities Exchange Act of 1934

                               (Amendment No. _)*



                         CSG Systems International, Inc.
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                                (Name of Issuer)

                     Common Stock, par value $.01 per share
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                         (Title of Class of Securities)

                                    126349109
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                                 (CUSIP Number)

                                 August 21, 2002
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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
13G is filed:
                [ ] Rule 13d-1(b)
                [X] Rule 13d-1(c)
                [ ] Rule 13d-1(d)

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions of  the Act  (however, see  the
Notes).






                               CUSIP NO. 126349109
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(1)     Names of Reporting Persons.  I.R.S. Identification Nos. of Above Persons
        (entities only):

                Ronald Juvonen
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(2)     Check the Appropriate Box if a Member of a Group (See Instructions)

          (a)                            (b)
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(3)     SEC Use Only
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(4)     Citizenship or Place of Organization:  United States
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Number of Shares Beneficially Owned by
   Each Reporting Person                      (5) Sole Voting Power:           *
                                              (6) Shared Voting Power:         *
                                              (7) Sole Dispositive Power:      *
                                              (8) Shared Dispositive Power:    *

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(9)     Aggregate Amount Beneficially Owned by Each Reporting Person:

        2,639,055*
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(10)    Check if  the Aggregate Amount  in Row (9) Excludes Certain  Shares (See
        Instructions)
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(11)    Percent of Class Represented by Amount in Row (9):   5.1%*
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(12)    Type of Reporting Person (See Instructions):    IA
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* The shares of the common stock, par value $.01 per share (the "Common Stock"),
are held by Downtown  Associates I, L.P., Downtown Associates II, L.P., Downtown
Associates III, L.P.,  Downtown  Associates IV, L.P. and Downtown  Associates V,
L.P. (collectively referred to as the "Downtown Funds").  The general partner of
the Downtown  Funds is Downtown  Associates,  L.L.C.  (the  "General  Partner").
Ronald Juvonen, as the Managing Member of the General Partner, has sole power to
vote and direct the  disposition  of all shares of the Common  Stock held by the
Downtown Funds.  For the purposes of Reg. Section  240.13d-3,  Ronald Juvonen is
deemed to beneficially own 2,639,055 shares, or 5.1% of the Common Stock.





Item 1(a).  Name Of Issuer:  CGS Systems International, Inc.


Item 1(b).  Address of Issuer's Principal Executive Offices:   7887 East
            Belleview Ave., Suite 1000, Englewood, Colorado  80111

Item 2(a).  Name of Person Filing:  Ronald Juvonen

Item 2(b).  Address  of  Principal  Business  Office  or,  if  None,  Residence:
            c/o  Downtown  Associates,  L.L.C.,  674 Unionville Road, Suite 105,
            Kennett Square, PA  19348

Item 2(c).  Citizenship:  United States

Item 2(d).  Title of Class of Securities: Common Stock, par value $.01 per share

Item 2(e).  CUSIP No.:  126349109

Item 3.     If  This  Statement  Is  Filed  Pursuant  to Section 240.13d-1(b) or
            240.13d-2(b) or (c), check whether the Person Filing is a

            Not Applicable.

Item 4.     Ownership

           (a)   Amount Beneficially Owned (as of August 21, 2002):  2,639,055*

           (b)   Percent of Class (as of August 21, 2002):                5.1%*

           (c)   Number of Shares as to which such person has:

               (i)   sole power to vote or to direct the vote                 *

               (ii)  shared power to vote or to direct the vote               *

               (iii) sole power to dispose or to direct the disposition of    *

               (iv)  shared power to dispose or to direct the disposition of  *


*    The shares  of the  common stock,  par value $.01 per  share  (the  "Common
     Stock"),  are held by Downtown  Associates I, L.P., Downtown Associates II,
     L.P.,  Downtown  Associates  III,  L.P.,  Downtown  Associates IV, L.P. and




     Downtown  Associates  V, L.P.  (collectively  referred to as the  "Downtown
     Funds").  The general partner of the Downtown Funds is Downtown Associates,
     L.L.C. (the "General  Partner").  Ronald Juvonen, as the Managing Member of
     the General  Partner,  has sole power to vote and direct the disposition of
     all of the Common  Stock held by the  Downtown  Funds.  For the purposes of
     Reg.  Section  240.13d-3,  Ronald  Juvonen  is deemed to  beneficially  own
     2,639,055 shares, or 5.1% of the Common Stock.


Item 5.  Ownership of Five Percent or Less of a Class

         Not Applicable.

Item 6.  Ownership of More Than Five Percent on Behalf of Another Person.

         Not Applicable.

Item 7.  Identification  and  Classification  of the  Subsidiary  Which Acquired
         the Security Being Reported on by the Parent Holding Company.

         Not Applicable.

Item 8.  Identification and Classification of Members of the Group.

         Not Applicable.

Item 9.  Notice of Dissolution of Group.

         Not Applicable.

Item 10.  Certification

          By  signing  below I  certify  that,  to the best of my knowledge  and
belief, the securities  referred to above were not acquired and are not held for
the purpose of or with the effect of changing or influencing  the control of the
issuer of such  securities  and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.







                                    SIGNATURE


         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.


                                                 August 30, 2002


                                                 /s/Ronald Juvonen
                                                 -------------------------------
                                                 Ronald Juvonen, in his capacity
                                                 as the Managing Member of
                                                 Downtown Associates, L.L.C.


      Attention: Intentional misstatements or omissions of fact constitute
                Federal criminal violations (See 18 U.S.C. 1001)