<PAGE>   1

                                                                    EXHIBIT 10.3


<TABLE>
<S>                                                <C>                                                          <C>
                                                                   BORROWER

                                                   Cybex Computer Products Corporation

[LOGO] FIRST COMMERCIAL BANK                                                                                    COMMERCIAL
                                                                                                                FIXED RATE
FIRST COMMERCIAL BANK OF HUNTSVILLE                                                                             PROMISSORY
301 WASHINGTON STREET                                                                                              NOTE
HUNTSVILLE, AL 35801
(205) 551-3300   "LENDER"                                             ADDRESS

                                                   4912 Research Drive
                                                   Huntsville, AL  35806
                                                   TELEPHONE NO.              IDENTIFICATION NO.
                                                   (205) 430-4000             630801728
</TABLE>

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------------------
   OFFICER           INTEREST        PRINCIPAL        FUNDING       MATURITY     CUSTOMER       LOAN
IDENTIFICATION         RATE           AMOUNT            DATE          DATE        NUMBER       NUMBER
<S>                  <C>          <C>                 <C>           <C>          <C>           <C>
LKS                   8.188%      $12,000,000.00      03/26/98      04/02/98
-------------------------------------------------------------------------------------------------------
GENERAL CORPORATE PURPOSES
-------------------------------------------------------------------------------------------------------
</TABLE>

PROMISE TO PAY: For value received, Borrower promises to pay to the order of
Lender the principal amount of TWELVE MILLION AND NO/100 Dollars
($12,000,000.00) plus interest on the unpaid principal balance at the rate and
in the manner described below, until all amounts owing under this Note are paid
in full. All amounts received by Lender shall be applied first to accrued,
unpaid interest, then to unpaid principal, and then to any late charges and
expenses, or in any other order as determined by Lender, in Lender's sole
discretion, as permitted by law.

INTEREST RATE: Interest shall be computed on the basis of THE ACTUAL NUMBER OF
DAYS OVER 360 DAYS per year. Interest on this Note shall be calculated and
payable at the fixed rate of 8.188% per annum.

DEFAULT RATE: If there is an Event of Default under this Note, the Lender may,
in its discretion, increase the interest rate on this Note to: PRE-MATURITY
RATE CONTINUES TO APPLY POST-MATURITY, or the maximum interest rate Lender is
permitted to charge by law, whichever is less.

PAYMENT SCHEDULE: Borrower shall pay the principal and interest according to
the following schedule:

A SINGLE PAYMENT OF THE UNPAID PRINCIPAL BALANCE PLUS ACCRUED INTEREST IS DUE
AND PAYABLE ON APRIL 02, 1998.


INTEREST SURCHARGE: Borrower agrees to pay an interest surcharge of $ N/A . The
interest surcharge is earned by Lender when paid and is not subject to refund;
however, if this Note is prepaid in full within 90 days after the date of this
Note, Borrower will receive a credit of a pro rata portion of the interest
surcharge, subject to Lender's right to retain a minimum surcharge of $25.00.

PREPAYMENT: This Note may be prepaid in part or in full on or before its
maturity date. If this Note contains more than one installment, any partial
prepayment will not affect the due date or the amount of any subsequent
installment, unless agreed to, in writing, by Borrower and Lender. If this Note
is prepaid in full, there will be: [X] No prepayment penalty. [ ] A prepayment
penalty of:


LATE CHARGE: If a payment is in default 10 days or more, Borrower will be
charged a late charge of: [ ]_____________% of the unpaid payment; [X] $10.00
or 5.00% of the unpaid payment, whichever is [X] greater, but not to exceed
$100.00; [ ] less.

SECURITY: To secure the payment and performance of obligations incurred under
this Note, Borrower grants Lender a security interest in all of Borrower's
right, title, and interest in all monies, instruments, savings, checking and
other accounts of Borrower (excluding IRA, Keogh, trust accounts and other
accounts subject to tax penalties if so assigned) that are now or in the future
in Lender's custody or control. [X] If checked, the obligations under this Note
are also secured by the collateral described in any security instrument(s)
executed in connection with this Note, and any collateral described in any
other security instrument(s) securing this Note or all of Borrower's
obligations.

   US GOVERNMENT TREASURY BILL MATURITY 4-2-98 IN THE MATURITY AMOUNT OF
   $12,000,000.00, CUSIP #9127944T8.

RENEWAL: [ ] If checked, this Note is a renewal, but not a satisfaction, of
Loan Number __________________.
--------------------------------------------------------------------------------
THE PERSONS SIGNING BELOW ACKNOWLEDGE THAT THEY HAVE READ, UNDERSTAND, AND
AGREE TO THE TERMS AND CONDITIONS OF THIS NOTE, INCLUDING THE PROVISIONS ON THE
REVERSE SIDE, AND FURTHER ACKNOWLEDGE RECEIPT OF AN EXACT COPY OF THIS NOTE.

Dated: MARCH 26, 1998

        CAUTION - IT IS IMPORTANT THAT YOU THOROUGHLY READ THE CONTRACT
                              BEFORE YOU SIGN IT.

<TABLE>
<S>                                                   <C>
BORROWER: CYBEX COMPUTER PRODUCTS CORPORATION         BORROWER:


BY: /s/ Doyle C. Weeks
--------------------------------------------------    --------------------------------------------------
DOYLE C. WEEKS
CHIEF FINANCIAL OFFICER

BORROWER:                                             BORROWER:



--------------------------------------------------    --------------------------------------------------



BORROWER:                                             BORROWER:



--------------------------------------------------    --------------------------------------------------



BORROWER:                                             BORROWER:



--------------------------------------------------    --------------------------------------------------
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<PAGE>   2

                              TERMS AND CONDITIONS

1.    EVENTS OF DEFAULT.  An Event of Default will occur under this Note in the
event that Borrower, any guarantor or any other third party pledging collateral
to secure this Note:

      (a)   fails to make any payment on this Note or any other indebtedness to
            Lender when due;
      (b)   fails to perform any obligation or breaches any warranty or
            covenant to Lender contained in this Note, any security instrument,
            or any other present or future written agreement regarding this or
            any other indebtedness of Borrower to Lender;
      (c)   provides or causes any false or misleading signature or
            representation to be provided to Lender;
      (d)   sells, conveys, or transfers rights in any collateral securing this
            Note without the written approval of Lender; or destroys, loses or
            damages such collateral in any material respect; or subjects such
            collateral to seizure, confiscation or condemnation;
      (e)   has a garnishment, judgment, tax levy, attachment or lien entered
            or served against Borrower, any guarantor, or any third party
            pledging collateral to secure this Note or any of their property;
      (f)   dies, becomes legally incompetent, is dissolved or terminated,
            ceases to operate its business, becomes insolvent, makes an
            assignment for the benefit of creditors, fails to pay debts as they
            become due, or becomes the subject of any bankruptcy, insolvency
            or debtor rehabilitation proceeding;
      (g)   fails to provide Lender evidence of satisfactory financial
            condition;
      (h)   has a majority of its outstanding voting securities sold,
            transferred or conveyed to any person or entity other than any
            person or entity that has the majority ownership as of the date of
            this execution of this Note; or
      (i)   causes Lender to deem itself insecure due to a significant decline
            in the value of any real or personal property securing payment of
            this Note, or Lender in good faith, believes the prospect of
            payment or performance is impaired.

2.    RIGHTS OF LENDER ON DEFAULT.  If there is an Event of Default under this
Note, Lender will be entitled to exercise one or more of the following remedies
without notice or demand (except as required by law):

      (a)   to declare the principal amount plus accrued interest under this
            Note and all other present and future obligations of Borrower
            immediately due and payable in full, such acceleration to be
            automatic and immediate if the Event of Default is a filing under
            the Bankruptcy Code;
      (b)   to collect the outstanding obligations of Borrower with or without
            resorting to judicial process;
      (c)   to cease making advances under this Note or any other agreement
            between Borrower and Lender;
      (d)   to take possession of any collateral in any manner permitted by law;
      (e)   to require Borrower to deliver and make available to Lender any
            collateral at a place reasonably convenient to Borrower and Lender;
      (f)   to sell, lease or otherwise dispose of any collateral and collect
            any deficiency balance with or without resorting to legal process;
      (g)   to set-off Borrower's obligations against any amounts due to
            Borrower including, but not limited to, monies, instruments, and
            deposit accounts maintained with Lender; and
      (h)   to exercise all other rights available to Lender under any other 
            written agreement or applicable law.

Lenders's rights are cumulative and may be exercised together, separately, and
in any order.  Lender's remedies under this paragraph are in addition to those
available at common law, including, but not limited to, the right of set-off.

3.    DEMAND FEATURE. [ ] If checked, this Note contains a demand feature.
Lender's right to demand payment, at any time, and from time to time, shall be
in Lender's sole and absolute discretion, whether or not any default has
occurred.

4.    FINANCIAL INFORMATION.  Borrower will at all times keep proper books and
account in which full, true and correct entries shall be made in accordance
with generally accepted accounting principles and will deliver to Lender,
within ninety (90) days after the end of each fiscal year of Borrower, a copy
of the annual financial statements of Borrower relating to such fiscal year,
such statements to include (i) the balance sheet of Borrower as at the end of
such fiscal year and (ii) the related income statement, statement of retained
earnings and statement of cash flow of Borrower for such fiscal year, prepared
by such certified public accountants as may be reasonably satisfactory to
Lender.  Borrower also agrees to deliver to Lender within fifteen (15) days
after filing same, a copy of Borrower's income tax returns and also, from time
to time, such other financial information with respect to Borrower as Lender
may request.

5.    MODIFICATION AND WAIVER.  The modification or waiver of any of Borrower's
obligations or Lender's rights under this Note must be contained in a writing
signed by Lender.  Lender may perform any of Borrower's obligations or delay or
fail to exercise any of its rights without causing a waiver of those
obligations or rights.  A waiver on one occasion will not constitute a waiver
on any other occasion.  Borrower's obligations under this Note shall not be
affected if Lender amends, compromises, exchanges, fails to exercise, impairs
or releases any of the obligations belonging to any co-borrower or guarantor or
any of its rights against any co-borrower, guarantor, the collateral or any
other property securing the obligations.

6.    SEVERABILITY.  If any provision of this Note is invalid, illegal or
unenforceable, the validity, legality and enforceability of the remaining
provisions shall not in any way be affected or impaired thereby.

7.    ASSIGNMENT.  Borrower agrees not to assign any of Borrower's rights,
remedies or obligations described in this Note without the prior written
consent of Lender, which consent may be withheld by Lender in its sole
discretion.  Borrower agrees that Lender is entitled to assign some or all of
its rights and remedies described in this Note without notice to or the prior
consent of Borrower.

8.    NOTICE.  Any notice or other communication to be provided to Borrower or
Lender under this Note shall be in writing and sent to the parties at the
addresses described in this Note or such other address as the parties may
designate in writing from time to time.

9.    APPLICABLE LAW.  This Note shall be governed by the laws of the state
indicated in Lender's address.  Unless applicable law provides otherwise,
Borrower consents to the jurisdiction of any court located in such state
selected by Lender, in its discretion, in the event of any legal proceeding
under this Note.

10.   COLLECTION COSTS.  If the original principal amount of this Note exceeds
$300, and if Lender hires an attorney who is not its salaried employee to
collect any amount due under this Note or enforce any right or remedy of
Lender, Borrower agrees to pay Lender's reasonable expenses and collection
costs, including reasonable attorneys' fees not exceeding 15% of the unpaid
debt after default.

11.   MISCELLANEOUS.  This Note is being executed primarily for commercial,
agricultural, or business purposes.  Borrower and Lender agree that time is of
the essence.  Borrower agrees to make all payments to Lender at any address
designated by Lender and in lawful United States currency.  Borrower and any
person who endorses this Note waives presentment, demand for payment, notice of
dishonor and protest and further waives any right to require Lender to proceed
against anyone else before proceeding against Borrower or said person.  All
references to Borrower in this Note shall include all of the parties signing
this Note, and this Note shall be binding upon the heirs, successors and
assigns of Borrower and Lender.  If there is more than one Borrower their
obligations under this Note shall be joint and several.  This Note represents
the complete and integrated understanding between Borrower and Lender regarding
the terms hereof.

12.   JURY TRIAL WAIVER.  BORROWER HEREBY WAIVES ANY RIGHT TO A TRIAL BY JURY
IN ANY CIVIL ACTION ARISING OUT OF, OR BASED UPON, THIS NOTE OR THE COLLATERAL
SECURING THIS NOTE.

13.   ADDITIONAL TERMS.


 
<PAGE>   3
                                    BORROWER
                      Cybex Computer Products Corporation

[FIRST COMMERCIAL BANK LOGO]

                                                            DISBURSEMENT 
                                                            INSTRUCTIONS

First Commercial Bank of Huntsville
301 Washington Street
Huntsvillle, AL 35801
(205) 551-3300   "LENDER"
                                   ADDRESS

                      4912 Research Drive
                      Huntsville, AL 35806
                      Telephone No.      Identification No.
                      (205) 430-4000     630801728

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<CAPTION>

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    OFFICER      INTEREST                                         FUNDING DATE/      MATURITY     CUSTOMER     LOAN
IDENTIFICATION     RATE         PRINCIPAL AMOUNT/CREDIT LIMIT    AGREEMENT DATE        DATE        NUMBER     NUMBER 
------------------------------------------------------------------------------------------------------------------------ 
<S>              <C>            <C>                             <C>                  <C>           <C>        <C> 
     LKS         8.188%         $12,000,000.00                     03/26/98          04/02/98
------------------------------------------------------------------------------------------------------------------------ 
  Borrower has borrowed money from Lender indicated above pursuant to a Promissory Note/Credit Agreement dated
  March 26, 1998  and Borrower instructs Lender to disburse the proceeds in the following manner:

AMOUNT DISBURSED TO BORROWER:                                                   $             0.00
                                                                                 -----------------
AMOUNT DRAWN TO PAY OR CREDIT TO BORROWER'S ACCOUNTS WITH LENDER:               $
                                                                                 -----------------
     ACCOUNT NUMBER CREDITED: 
                                                                                 -----------------
     ACCOUNT NUMBER CREDITED: 
                                                                                 -----------------
     ACCOUNT NUMBER CREDITED: 
                                                                                 -----------------
     ACCOUNT NUMBER CREDITED: 
                                                                                 -----------------
     ACCOUNT NUMBER CREDITED: 
                                                                                 -----------------
AMOUNT OF LOAN PROCEEDS PAID TO OTHERS ON THE BORROWER'S BEHALF:                $    12,000,000.00
                                                                                 -----------------
     PAYEE:   First Commercial Bank-Birmingham                                                    
                                                                                 -----------------
     PAYEE:                                                                    
                                                                                 -----------------
     PAYEE:                                                                    
                                                                                 -----------------
     PAYEE:                                                                    
                                                                                 -----------------
     PAYEE:                                                                    
                                                                                 -----------------
     PAYEE:                                                                    
                                                                                 -----------------
     PAYEE:                                                                    
                                                                                 -----------------
     PAYEE:                                                                    
                                                                                 -----------------
     PAYEE:                                                                    
                                                                                 -----------------
     PAYEE:                                                                    
                                                                                 -----------------
          

                                                              PAID IN CASH     ADDED TO LOAN AMOUNT

AMOUNT PAID TO PUBLIC OFFICIALS:                             $                  $
                                                              -------------      -----------------
AMOUNT PAID TO INSURANCE COMPANIES: 
                                                              -------------      -----------------
AMOUNT PAID TO APPRAISERS: 
                                                              -------------      -----------------
AMOUNT PAID TO CREDIT REPORTING AGENCIES:
                                                              -------------      -----------------
TITLE EXAMINATION: 
                                                              -------------      -----------------
SETTLEMENT/CLOSING FEE: 
                                                              -------------      -----------------
TITLE INSURANCE BINDER:
                                                              -------------      -----------------
ATTORNEY:
                                                              -------------      -----------------
DOCUMENT PREPARATION FEE:
                                                              -------------      -----------------
NOTARY:
                                                              -------------      -----------------
SURVEYOR:
                                                              -------------      -----------------
PEST INSPECTOR:
                                                              -------------      -----------------
ABSTRACT/TITLE SEARCH:
                                                              -------------      -----------------
TITLE INSURER:
                                                              -------------      -----------------
CITY/COUNTY TAX DEED/MORTGAGE:
                                                              -------------      -----------------
STATE TAX DEED/MORTGAGE:
                                                              -------------      -----------------
HAZARD INSURANCE PREMIUM:
                                                              -------------      -----------------
FLOOD INSURANCE PREMIUM:
                                                              -------------      -----------------

                                                              -------------      -----------------

                                                              -------------      -----------------

                                                              -------------      -----------------

                                                              -------------      -----------------

                                                              -------------      -----------------
Loan Origination Fee
                                                              -------------      -----------------
Points/Discount
                                                              -------------      -----------------
Lender's Inspection Fee
                                                              -------------      -----------------
Assumption Fee
                                                              -------------      -----------------

                                                              -------------      -----------------
   Loan Processing Fee
                                                              -------------      -----------------
TOTAL FEES PAID IN CASH:                                              50.00
                                                              -------------      -----------------
TOTAL FEES FINANCED WITH LOAN:                               $        50.00
                                                              -------------      -----------------
                                                                                $              N/A
                                                                                 -----------------

--------------------------------------------------------------------------------------------------
Dated: March 26, 1998

BORROWER: Cybex Computer  Products Corporation       BORROWER: 

By: /S/ Doyle C. Weeks 
----------------------------------------------       ---------------------------------------------
Doyle C. Weeks
Chief Financial Officer

BORROWER:                                            BORROWER:


----------------------------------------------       ---------------------------------------------


BORROWER:                                            BORROWER:


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BORROWER:                                            BORROWER:


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