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


                                      
                                  FORM 10-Q/A
                                                  
     
        
   X      Quarterly Report Pursuant to Section 13 or 15(d) of the
--------  Securities Exchange Act of 1934 for the quarterly period ended
          September 30, 1997                                            
             

________  Transition Report Pursuant to Section 13 or 15(d) of the Securities
          Exchange Act of 1934 for the transition period from _____ to _____.

                       Commission File Number:  0-27468

                             ULTRADATA CORPORATION
            (Exact name of registrant as specified in its charter)

                  Delaware                                  94-2746681
        (State or other jurisdiction                     (I.R.S. Employer
      of incorporation or organization)                 Identification No.)


   5000 Franklin Drive, Pleasanton, CA                       94588-3031
(Address of principal executive officers)                    (Zip Code)


              Registrant's telephone number, including area code:
                                  510/463-8356

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.

                            Yes    X     No
                                -------     -------

As of November 4, 1997, Registrant had outstanding 7,607,133 shares of Common
Stock, $.001 par value.



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<PAGE>
 
                            ULTRADATA CORPORATION
                           Condensed Balance Sheets
                      (In thousands, except share data)
 
<TABLE>
<CAPTION>
                                                                            Sept 30,           Dec 31,
                                                                          -----------       -----------
                             Assets                                           1997              1996
                            -------                                       -----------       -----------
                                                                          (Unaudited)
<S>                                                                       <C>               <C>
Current assets:
  Cash and cash equivalents                                                 $ 1,140            $ 1,583
  Short term investments                                                        402              1,420
  Restricted cash                                                               596                 --
  Trade accounts receivable, net                                              3,316              6,586
  Unbilled revenues                                                           2,906              3,870
  Inventories                                                                   804              1,173
  Prepaid expenses and other current assets                                     631              1,027
  Income taxes receivable                                                         5                958
                                                                            -------            -------
    Total current assets                                                      9,800             16,617
Property and equipment, net                                                   4,495              3,532
Other assets                                                                     --                254
                                                                            -------            -------
                                                                            $14,295            $20,403
                                                                            =======            =======
 
              Liabilities and Stockholders' Equity
              ------------------------------------
 
Current liabilities:
  Bank borrowings                                                           $   596            $    96
  Accounts payable                                                            2,033              3,659
  Accrued expenses                                                            1,199              2,008
  Deferred revenue and customer advances                                      2,535              3,508
                                                                            -------            -------
    Total current liabilities                                                 6,363              9,271
Deferred revenue and customer advances                                        1,329              1,313
Bank borrowing, excluding current portion                                        --                323
                                                                            -------            -------
    Total liabilities                                                         7,692             10,907
                                                                            -------            -------
 
Stockholders' equity:
Preferred stock; par value $.001; 2,000,000 shares authorized; none
outstanding                                                                      --                 --
Common stock; par value $.001; 23,000,000 shares authorized;                   
7,607,133 and 7,526,313 shares issued and outstanding in 1997 and 1996,    
respectively                                                                      8                  7
Additional paid in capital                                                   15,202             14,941
Accumulated deficit                                                          (8,607)            (5,452)
                                                                            -------            -------
    Total stockholders' equity                                                6,603              9,496
                                                                            -------            -------
                                                                            $14,295            $20,403
                                                                            =======            =======
</TABLE>
 
See accompanying notes to condensed financial statements
 

                                       1
<PAGE>
 
                             ULTRADATA Corporation
                      Condensed Statements of Operations
                       (In thousands, except share data)
                                  (Unaudited)
 
<TABLE>    
<CAPTION>
                                               Three Months Ended                  Nine Months Ended 
                                                  September 30,                      September 30,
                                             ----------------------             ----------------------
                                               1997          1996                 1997           1996
                                             --------      --------             --------      --------
<S>                                          <C>           <C>                  <C>           <C>
Revenues:                                               
  Software                                    $2,076        $ 1,929              $ 5,216        $10,059
  Maintenance                                  2,540          2,290                7,647          6,246
  Services and other                           1,378          1,878                4,668          5,807
                                              ------        -------              -------        -------
    Subtotal                                   5,994          6,097               17,531         22,112
  Hardware                                       743          2,595                4,425         11,629
                                              ------        -------              -------        -------
    Total revenues                             6,737          8,692               21,956         33,741
                                              ------        -------              -------        -------
 
Cost of revenues:
  Software                                       362            408                  862          2,077
  Maintenance                                  1,497          1,359                4,629          3,553
  Services and other                           1,300          1,733                4,330          5,598
  Hardware                                       506          1,801                3,161          8,097
                                              ------        -------              -------        -------
    Total cost of revenues                     3,665          5,301               12,982         19,325
                                              ------        -------              -------        -------
    Gross margin                               3,072          3,391                8,974         14,416
                                              ------        -------              -------        -------
 
Operating expenses:
  Product development                          1,104          1,627                3,601          4,402
  Selling, general and administrative          2,285          4,376                9,358         11,125
  Gain on transfer of service bureau                                                         
      contracts                                 (558)            --                 (558)            --
                                              ------        -------              -------        -------
    Total operating expenses                   2,831          6,003               12,401         15,527
                                              ------        -------              -------        -------
    Operating (loss) income                      241         (2,612)              (3,427)        (1,111)
Interest income, net                              19             96                   18            316
Other income                                      --             --                  254             --
                                              ------        -------              -------        -------
Income (loss) before income taxes                260         (2,516)              (3,155)          (795)
Income tax benefit                                --           (931)                  --           (294)
                                              ------        -------              -------        -------
    Net income (loss)                         $  260        $(1,585)             $(3,155)       $  (501)
                                              ======        =======              =======        =======
Net income (loss) per common and common
equivalent share                              $ 0.03        $ (0.21)             $ (0.42)       $ (0.07)
                                              ======        =======              =======        =======
Shares used in per share computations          7,673          7,432                7,570          7,086
 
</TABLE>      
 
           See accompanying notes to condensed financial statements
 

                                       2
<PAGE>
 
                             ULTRADATA CORPORATION
                      Condensed Statements of Cash Flows
                                 In thousands
                                  (Unaudited)
<TABLE>
<CAPTION>
                                                             Nine Months Ended
                                                                September 30,
                                                           ---------------------
                                                             1997         1996
                                                           -------       --------
<S>                                                        <C>           <C>
Cash flows from operating activities:                    
  Net loss                                                 $(3,155)      $   (501)
  Adjustments to reconcile net loss to net cash                            
  provided by (used for) operating activities:                             
    Depreciation and amortization                              958            781
    Deferred income taxes                                       --            181
    Gain on sale of joint venture                             (238)            --
    Loss on disposition of property and equipment               17             --
    Equity in earnings of unconsolidated subsidiary            (16)           (62)
                                                                           
    Changes in operating assets and liabilities:                           
      Trade accounts receivable                              3,270         (2,061)
      Unbilled revenues                                        964         (3,755)
      Inventories                                              369           (535)
      Prepaid expenses and other assets                        404           (617)
      Income taxes receivable                                  953             --
      Accounts payable                                      (1,626)        (2,364)
      Accrued expenses                                        (809)           154
      Income taxes payable                                      --           (107)
      Deferred revenue and customer advances                  (957)        (1,725)
                                                           -------       --------
    Net cash (used for) provided by operating activities      (134)       (10,611)
                                                           -------       --------
Cash flows from investing activities:
  Capital expenditures                                      (2,130)        (1,737)
  Proceeds from disposition of service bureau assets           192             --
  Sale of investment in joint venture                          500             --
  Sale of short term investments                             1,018             --
  Decrease of stockholders notes receivable                     --          1,453
                                                           -------       --------
    Net cash used for investing activities                    (420)          (284)
                                                           -------       --------
Cash flows from financing activities:
  Bank borrowings                                              500             --
  Repayment of debt                                           (323)        (1,233)
  Restricted cash                                             (596)            --
  Net proceeds from issuance of stock                          262             --
  Net proceeds from initial public offering                     --         14,750
                                                           -------       --------
    Net cash provided by (used for) financing activities      (157)        13,517
                                                           -------       --------
Net increase (decrease) in cash                               (443)         2,622
Cash and cash equivalents at beginning of period             1,583          1,124
                                                           -------       --------
Cash and cash equivalents at end of period                 $ 1,140       $  3,746
                                                           =======       ========
</TABLE>
 
           See accompanying notes to condensed financial statements

                                       3
<PAGE>
 
                             ULTRADATA CORPORATION
                    Notes to Condensed Financial Statements
                          September 30, 1997 and 1996


1. Basis of Presentation

These unaudited financial statements have been prepared in accordance with the
instructions for Form 10-Q and therefore certain information and footnote
disclosures normally contained in financial statements prepared in accordance
with generally accepted accounting principles have been condensed or omitted.
These statements should be read in conjunction with the financial statements
contained in the Company's report on Form 10-K for the year ended December 31,
1996.

The accompanying unaudited financial statements of the Company reflect all
adjustments of a normal recurring nature which are, in the opinion of
management, necessary to present a fair statement of the financial position as
of September 30, 1997 and the results of operations and cash flows for the
interim periods presented.

2.  Revenue Recognition

The Company recognizes revenues from licenses of computer software provided that
a noncancelable license agreement has been signed, the software and related
documentation have been shipped, there are no material uncertainties regarding
customer acceptance, collection of the resulting receivable is deemed probable,
and no other significant vendor obligations exist.  Maintenance revenues are
deferred and recognized over the related contract period, generally three months
to five years.  Services and other revenues generated from professional
consulting and training services and software customization services are
recognized as the services are performed.  Hardware revenues are recognized upon
shipment.

3. Recent Accounting Pronouncements

The Financial Accounting Standards Board (FASB) recently issued Statement of
Financial Accounting Standards (SFAS) No. 128, "Earnings Per Share" which is
effective for annual and interim periods ending after December 15, 1997.  SFAS
No. 128 requires the presentation of basic earnings per share ("EPS") and, for
companies with complex capital structures or potentially dilutive securities,
such as convertible debt, options and warrants, diluted EPS.  Had SFAS No. 128
been effective for the quarter and nine months ended September 30, 1997, basic
EPS and diluted EPS would not have been significantly different from the
reported net income or loss per share.  The FASB also recently issued SFAS No.
130, "Reporting Comprehensive Income" and SFAS No. 131, "Disclosures about
Segments of an Enterprise and Related Information."  SFAS No. 130 and 131 are
effective for fiscal 1998.  The company is currently evaluating the impact of
these statements on the financial statements.

                                       4
<PAGE>
     

11.01     Computation of Earnings (Loss) per Share (in thousands
          except per share data)

     
<TABLE>    
<CAPTION>
                                                     Three Months                    Nine Months
                                                        Ended                           Ended
                                                    September 30,                   September 30,
                                          --------------------------------------------------------------
                                                   1997             1996          1997             1996
                                                 -------          --------      --------         -------
<S>                                              <C>              <C>           <C>              <C>
Net income (loss)                                $  260           ($1,585)      ($3,155)           ($501)
                                                 =======          =======       =======           ======
 
Weighted average outstanding shares               7,607             7,432         7,570            7,086
Common stock equivalents                             66                --            --               -- 
                                                 =======          =======       =======           ======
                                                  7,673             7,432         7,570            7,086
                                                 =======          =======       =======           ======
 
Net income (loss) per common and common
 equivalent share                                $ 0.03            $(0.21)      $(0.42)           $(0.07)
                                                =======           =======       =======           ======
</TABLE>      



                                       5

<PAGE>
 
                                   SIGNATURES

        
Pursuant to the requirements of the Securities Exchange Act of 1934, registrant
has duly caused this Amendment No. 1 to Form 10-Q to be signed on its behalf by
the undersigned, thereunto duly authorized.    
    
     
                             ULTRADATA CORPORATION
    
Date November 20, 1997      By /s/ ROBERT J. MAJTELES
                                   Robert J. Majteles
                                   President and Chief Executive Officer
    
Date November 20, 1997      By /s/ PHILIP D. RANGER
                                   Philip D. Ranger
                                   Vice President and Chief Financial Officer
     
                                       6