FOURTH AMENDMENT TO AGREEMENT OF SALE


     THIS FOURTH AMENDMENT TO AGREEMENT OF SALE ( "Amendment") is made and
entered into as of the 31st day of January, 1997, between CEEBRAID-SIGNAL
CORPORATION, a Florida corporation ("Purchaser"), GLENEAGLES INVESTORS A REAL
ESTATE LIMITED PARTNERSHIP, an Illinois Limited Partnership ("Seller").  

                                  WITNESSETH:

     WHEREAS, Seller and Purchaser are parties to that certain Agreement of
Sale entered into as of October 24, 1996 (as heretofore amended, the "
Agreement"), pursuant to which Seller agreed to sell to Purchaser, and
Purchaser agreed to purchase from Seller, the "Property" (as defined in the  
Agreement); and

     WHEREAS, Seller and Purchaser  now desire to amend the Agreement pursuant
to the terms and provisions set forth herein.

     NOW, THEREFORE, for and in consideration of the premises and mutual
agreements contained herein, the payment of Ten and No/100 Dollars ($10.00) and
other good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, Seller and Purchaser hereby agree as follows:

     1.   All capitalized terms used in this amendment, to the extent not
otherwise expressly defined herein, shall have the same meanings ascribed to
such terms in the  Agreement.

     2.   Lines  1 and  2 of paragraph 8 of the  Agreement are hereby deleted
in their entirety, and the following is hereby inserted in lieu thereof: 

     "8. CLOSING.  The Closing ("Closing") of this transaction shall be on
February 28, 1997 ("Closing Date"), at the office of the title insurer, at this
time Seller shall deliver...."

     3.   Purchaser , simultaneously with the execution of this Amendment, is
depositing an additional $100,000 Earnest Money Deposit with Seller, which
amount shall be credited against the Purchase Price at Closing.  At this time,
the Earnest Money Deposit totals $300,000.  In the event of default of
Purchaser under this Agreement, Seller's remedy shall be limited to retaining
the $300,000 Earnest Money Deposit as stated in Paragraph 10 of the Agreement,
except as otherwise provided in Paragraphs 16.b and 17 of the Agreement.

     4.   Except as amended herein, the terms and conditions of the Agreement  
shall continue in full force and effect and are hereby ratified in their
entirety.

     5.   This Amendment may be executed in multiple counterparts, each of
which shall be deemed  an original, but all of which  shall constitute one in
the same agreement.

     6.   The parties herein agree and acknowledge that a  facsimile copy of
any party's signature on this Amendment shall be enforceable against such party
as an original.
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     Executed as of the date first written above.


                                   PURCHASER:

                                   CEEBRAID-SIGNAL CORPORATION,
                                   a Florida corporation

                                   By:   /s/ Richard Schlesinger
                                        ----------------------------------
                                   Name:     Richard Schlesinger
                                        ----------------------------------
                                   Its:      Managing Director
                                        ----------------------------------


                                   SELLER:

                                   GLENEAGLES INVESTORS A REAL ESTATE 
                                   PARTNERSHIP, an Illinois limited partnership

                                   By:  Balcor Equity Partners-IV, an
                                        Illinois general partnership,
                                        its general partner

                                        By:  The Balcor Company, a Delaware 
                                             corporation, a general partner

                                        By:   /s/ James E. Mendelson
                                             --------------------------------
                                        Name:     James E. Mendelson
                                             --------------------------------
                                        Its:      Sr. V.P.
                                             --------------------------------
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