ASSUMPTION OF INDEBTEDNESS AGREEMENT


By this present Assumption of Indebtedness Agreement (this "Agreement"), the
parties below:



Algar S.A. - Empreendimentos e Participacoes, a company duly organized and
validly existing under the laws of the Federal Republic of Brazil, with head
offices in the City of Uberlandia, State of Minas Gerais, at Avenida Alexandrino
Garcia, 2689, Distrito Industrial, enrolled before the National Registry of
Legal Entities (Cadastro Nacional da Pessoa Juridica - CNPJ) under
No.17.835.026/0001-52, herein represented by its duly authorized representative
(hereinafter referred to as "ALGAR"); and

Xtal Fibras Opticas S.A., a corporation duly organized and validly existing
under the laws of the Federal Republic of Brazil, with head offices in the City
of Uberlandia, State of Minas Gerais, at Avenida Alexandrino Garcia, 2689,
Distrito Industrial, enrolled before the National Registry of Legal Entities
(CNPJ) under No. 71.340.707/0001-95, herein represented by its duly authorized
representative (hereinafter referred to as "XTAL"); (ALGAR and XTAL jointly
referred to as "Parties")

WHEREAS the Parties executed, on December 1st, 1998, an Assumption of
Indebtedness Agreement, whereby ALGAR assumed the debts of XTAL before several
Banks, in the total amount of R$ 4.986.464,86 (four million, nine hundred and
eighty-six thousand, four hundred and sixty-four Reais and eighty-six cents)
(the "First Agreement")

WHEREAS the Parties executed, on December 31st, 1998, an Assumption of
Indebtedness Agreement, whereby ALGAR assumed the debts of XTAL before its
supplier Kanematsu Corporation, in the total amount of R$ 4.301.386,02 (four
million, three hundred and one thousand, three hundred and eighty-six Reais and
two cents) (the "Second Agreement")WHEREAS the Parties also executed on December
31st, 1998, an Assumption of Indebtedness Agreement by means of which ALGAR
assumed the debts of XTAL before several Banks, in the total amount of R$
9.619.751,58 (nine million, six hundred and nineteen thousand, seven hundred and
fifty-one Reais and fifty-eight cents) (the "Third Agreement" and, jointly with
the First Agreement and Second Agreement, hereinafter referred to as the
"Agreements")

WHEREAS part of the debts assumed by ALGAR by means of the Agreements have been
paid;

WHEREAS the parties desire to amend and consolidate the terms and conditions of
the Agreements;

NOW THEREFORE, the Parties have agreed to execute this present Assumption of
Indebtedness Agreement , pursuant to the following terms and conditions:

SECTION 1 - PURPOSE

1.1      The purpose of this present Agreement is to amend and consolidate the
         terms and conditions of the Agreements, that will be, as of the date
         hereof, subject to the terms and conditions established in this
         agreement.

SECTION 2 - CONSOLIDATION

2.1      ALGAR, ,upon the payment of part of the debts assumed by it in the
         Agreements, does hereby assume the debts of XTAL listed below,
         equivalent on the date hereof to R$ 9,350,357.93 (nine million, three
         hundred and fifty thousand, three hundred and fifty-seven Reais and
         ninety-three cents),, being further established that besides the
         principal amount, Algar will also bear the interest when due and the
         financial charges agreed in the original agreements, according to the
         copies of the documents attached hereto.


<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------
     Execution Date         Maturity Date         Financial                 Principal Amount       Amount in R$
                                                  Institution                                      on June 20th, 2000
-----------------------------------------------------------------------------------------------------------------------
<S>                         <C>                   <C>                        <C>                 <C>
       20/06/1996           16/08/2000            Unibanco                   GBP 125,551.55        *342,646.51
                            15/02/2001                                       GBP 125,551.55         342,646.51
                            15/08/2001                                       GBP 125,551.55         342,646.51
                            15/02/2002                                       GBP 125,551.55         342,646.51
-----------------------------------------------------------------------------------------------------------------------
       23/07/1997           31/08/2000            Dresdner                   US$ 288,000.00       **520,502.40
                            26/09/2000                                       US$ 384,000.00         694,003.20
-----------------------------------------------------------------------------------------------------------------------
       09/11/1998           19/09/2000             Brascan                   US$ 1,500,000.00     2,710,950.00
-----------------------------------------------------------------------------------------------------------------------
       15/12/1999           19/10/2000             Brascan                   US$ 993,300.11       1,795,191.29
-----------------------------------------------------------------------------------------------------------------------
       20/12/1999           19/10/2000             Brascan                   US$ 1,250,000.00     2,259,125.00
-----------------------------------------------------------------------------------------------------------------------
                  Total                                                                           9,350,357.93
-----------------------------------------------------------------------------------------------------------------------
</TABLE>

* the conversion of the Great Britain Pound was effected  considering  the sales
exchange  rate of June  19th.,2000  of 2.72913

** the  conversion  of the United States  Dollar was effected considering the
sales exchange rate of June 19th.,2000 of 1.8073


SECTION 3 - MISCELLANEOUS

3.1      Any variation, modification or amendment to the terms of this agreement
         shall not have any effect, unless same is written and executed by the
         Parties.

3.2      This present assumption of debt is executed on an irrevocable and
         irreversible basis and its performance is binding upon the Parties and
         their respective successors, at any title.


SECTION 4 - JURISDICTION

4.1      The PARTIES elect the court of the city of Uberlandia, State of Minas
         Gerais to solve any conflict in connection with this Agreement.

         Uberlandia (MG), June 20th., 2000



Algar S.A. - Empreendimentos e Participacoes


-----------------------------------------
By:
Title:



Xtal Fibras Opticas S.A.


-----------------------------------------
By:
Title: