[Inventory Note]

PROMISSORY NOTE

DIGITAL LIGHTWAVE, INC.

$2,741,095.94

Effective Date: May 1, 2003

1.

Promise to pay.  Digital Lightwave, Inc. (“Maker”), a Delaware corporation,
15550 Lightwave Drive, Clearwater, FL 33760, for value received, promises to pay
to the order of Jabil Circuit, Inc. (“Jabil”) at 10560 9th Street North, St.
Petersburg, FL 33716, or at such other place as the holder of this Note
designates in writing to Maker, the principal amount of TWO MILLION SEVEN
HUNDRED FORTY ONE THOUSAND NINETY FIVE AND 94/100 DOLLARS (U.S. $2,741,095.94)
and to pay interest as required under this Note.

2.

Interest rate.  Maker shall pay interest on the outstanding principal amount of
this Note at a rate of six percent (6%) per year.

3.

Payments.  This Note matures on October 1, 2004, and Maker shall pay all unpaid
principal and accrued interest in full on October 1, 2004.   Payments made by
Maker to Jabil for certain "Existing Inventory" will be credited as payments on
this Note as provided for in the Forbearance Agreement between Maker and Jabil
dated on or about the same date as this Note.

4.

Application and form of payments.  Payments will be applied first to accrued
interest and then to principal, and all interest on this Note will be computed
on the basis of the actual number of days elapsed over a 360-day year.  Payments
of interest and principal must be made in such coin or currency of the United
States of America as at the time of payment is legal tender for the payment of
public and private debts.  Payments received after 2:00 p.m. will be treated as
being received on the next banking day.

5.

Prepayment, late fee, interest on default, and maximum interest.  Maker may
prepay all or any portion of this Note without penalty. Partial prepayments will
be applied against required principal installments in the inverse order of their
maturities.  Therefore, partial prepayments will not affect the due date of any
required installments under the Note until the Note is paid in full.  Maker
agrees to pay a late fee equal to five percent of any payment of either
principal or interest that is not paid within five days of the date the payment
is due.  Interest on all amounts not paid when due after maturity, acceleration,
or otherwise, will accrue and is payable at the rate of 18 percent per year.
 Notwithstanding anything in this Note to the contrary, the annual rate of
interest payable on this Note is limited to the maximum rate of interest now
allowed by applicable law or any higher rate of interest allowed because of a
future amendment to applicable law.  If any payment of interest, or any charge
in the nature of interest, under this Note would cause the annual interest rate
of this Note to exceed this limitation, Jabil shall credit the excess amount as
a payment of principal under this Note or, if Maker so requests, return the
excess amount to Maker.

6.

Acceleration in Event of Transfer of Assets.  Maker agrees that the full
principal and accrued interest on this Note will be immediately due and payable
upon the sale, transfer, seizure, or any other disposition of (a) all or
substantially all of Maker's assets, which the parties agree includes any
disposition of the assets (not including the sale of inventory in the ordinary
course of business) related to the (a) Network Information (or "NIC") product
line, (b) the Network Access Agents (or "NAA") product line, or (c) the Optical
Test System product line acquired from Tektronix, Inc.  In addition, in the
event of any sale, transfer, seizure or other disposition of assets (not
including the sale of inventory in the ordinary course of business) with a fair
market value in excess of $2,000,000 in the aggregate during any six-month
period, Maker shall pay the Holder of this Note at least the greater of (a)
thirty three percent (33%) of the proceeds of any such sales net of cost
directly related to the sales, or (b) an amount equal to the total proceeds paid
to any other creditor of Maker.

7.

Default and remedies.  The occurrence of any of the following events constitutes
a “Default”:

(a)

The nonpayment when due of any interest or principal under this Note or any
other liability, obligation, or indebtedness  (including without limitation the
$2,838,904.06 promissory note dated on or about the same date as this Note)
owing from Maker to Jabil, whether at maturity, by acceleration, or otherwise;

(b)

A breach by Maker of any representation, warranty, or covenant contained in this
Note or any other agreement between Maker and Jabil;

(c)

The initiation of an action or proceeding for the dissolution, termination or
liquidation of Maker;

(d)

A determination by Jabil that any representation or warranty made by Maker to
Jabil is now, or was when made, materially untrue or misleading;

(e)

The insolvency, appointment of a custodian, trustee or receiver for Maker, or
Maker files (or any creditor files against Maker) a petition seeking relief
under any bankruptcy, insolvency, reorganization, or other debtor relief law;

(f)

A lien not expressly approved in writing by Jabil is placed upon or attaches to
any property of Maker, except:  (i) liens and security interests of Jabil; (ii)
liens securing the payment of taxes, either not yet overdue or the validity of
which are being contested in good faith by appropriate proceedings diligently
pursued and available to Maker and with respect to which adequate reserves have
been set aside on its books; (iii) non-consensual statutory liens (other than
liens securing the payment of taxes) arising in the ordinary course of Maker’s
business to the extent: (A) such liens secure indebtedness which is not overdue
or (B) such liens secure indebtedness relating to claims or liabilities which
are fully insured and being defended at the sole cost and expense and at the
sole risk of the insurer or being contested in good faith by appropriate
proceedings diligently pursued and available to Maker, in each case prior to the
commencement of foreclosure or other similar proceedings and with respect to
which adequate reserves have been set aside on its books; (iv) zoning
restrictions, easements, licenses, covenants and other restrictions affecting
the use of real property which do not interfere in any material respect with the
use of such real property or ordinary conduct of the business of Maker as
presently conducted thereon or materially impair the value of the real property
which may be subject thereto; (v) purchase money security interests in equipment
(including capital leases) and purchase money mortgages on real estate not to
exceed $50,000 in the aggregate at any time outstanding so long as such security
interests and mortgages do not apply to any property of Maker other than the
equipment or real estate so acquired, and the indebtedness secured thereby does
not exceed the cost of the equipment or real estate so acquired, as the case may
be; and (vi) any lien on the property of Maker existing as of the date of this
Note.;

(g)

The entry of a judgment or issuance of a writ of execution, garnishment, levy,
attachment or similar process related to any judgment for the payment of money
against Maker in excess of $50,000 in any one case or in excess of $50,000 in
the aggregate and shall remain undischarged or unvacated for a period in excess
of thirty (30) days or execution shall at any time not be effectively stayed, or
any judgment other than for the payment of money, or injunction, attachment,
garnishment or execution is rendered against Maker or any of its assets.
 However, the entry of the judgment (the "Joseph Judgment") in favor of Seth P.
Joseph for approximately 4.8 million will not constitute a default under this
Note unless and until there is a seizure of any assets pursuant to a writ of
execution or otherwise by the holder of (or any successor in rights to) the
Joseph Judgment; or

(h)

A determination by Jabil that a material adverse change has occurred in the
financial condition of Maker since the financial condition of Maker was
disclosed to Jabil in connection with this Note.

Upon the occurrence of a Default and at any time thereafter, Jabil, at its
option and as often as it desires, may declare all liabilities, obligations, and
indebtedness, including this Note, to be immediately due and payable without
demand, notice, or presentment.

8.

Payment of costs.  Maker shall pay all costs incurred by the holder of this Note
in enforcing or collecting this Note and enforcing each agreement executed in
connection with this Note (including any agreement under which real or personal
property is pledged as security for this Note), including without limitation all
attorneys’ fees, costs, and expenses incurred in all matters of interpretation,
enforcement, and collection, before, during, and after demand, suit, proceeding,
trial, appeal, and post-judgment collection efforts as well as all costs and
fees incurred by the holder of this Note in connection with any bankruptcy,
reorganization, or similar proceeding (including efforts to obtain relief from
any stay) if Maker or any other person or entity liable for the indebtedness
represented by this Note becomes involved in any bankruptcy, reorganization, or
similar proceeding.

9.

Waiver and consents.  Maker and every other person liable at any time for
payment of this Note waives presentment, protest, notice of protest, and notice
of dishonor.  Maker expressly consents to all extensions and renewals of this
Note (as a whole or in part) and all delays in time of payment or other
performance under this Note that the holder of this Note grants at any time and
from time to time, without limitation and without any notice to or further
consent of Maker.  Maker agrees that its obligations under this Note are
independent of the obligations of any other person or entity that now or later
is obligated to pay this Note.  Maker also agrees that Jabil may release any
security for or other obligor of this Note or waive, extend, alter, amend, or
modify the Note or otherwise take any action that varies the risk of Maker
without releasing or discharging Maker from Maker’s obligation to repay this
Note.

10.

VENUE AND WAIVER OF JURY TRIAL.  MAKER FURTHER AGREES THAT VENUE FOR EACH
ACTION, SUIT, OR OTHER LEGAL PROCEEDING ARISING UNDER OR RELATING TO THIS NOTE
OR ANY AGREEMENT SECURING OR RELATED TO THIS NOTE SHALL BE THE COUNTY COURT OR
CIRCUIT COURT LOCATED IN HILLSBOROUGH COUNTY, FLORIDA, AND MAKER HEREBY WAIVES
ANY RIGHT TO SUE OR BE SUED IN ANY OTHER COUNTY IN FLORIDA OR ANY OTHER STATE.
  MAKER AND JABIL KNOWINGLY, VOLUNTARILY, AND INTENTIONALLY WAIVE ALL RIGHTS TO
A JURY TRIAL IN ANY LAWSUIT, PROCEEDING, COUNTERCLAIM, OR OTHER LITIGATION
ARISING UNDER OR RELATING TO THIS NOTE OR ANY AGREEMENT RELATING TO THIS NOTE.
 MAKER AND JABIL HAVE FULLY DISCUSSED THIS PROVISION AND AGREE THAT THIS WAIVER
IS SUBJECT TO NO EXCEPTIONS AND WAS A MATERIAL INDUCEMENT FOR JABIL TO AGREE TO
ACCEPT THIS NOTE.

11.

Miscellaneous.  The headings preceding the text of the sections of this Note
have been inserted solely for convenience of reference and do not limit or
affect the meaning, interpretation, or effect of this Note or the sections.  The
validity, construction, interpretation, and enforceability of this Note are
governed by the laws of the State of Florida, excluding its laws relating to the
resolution of conflicts of laws of different jurisdictions.  Each required
notice, consent, or approval, if any, under this Note will be valid only if it
is given in writing (or sent by telex, telegram, or telecopy and promptly
confirmed in writing) and addressed by the sender to the recipient’s address
that is listed in this Note or to such other address as either party may
designate by written notice to the other party.  A validly given notice,
consent, or approval will be effective on receipt if hand delivered to the
recipient or the day it (or the written confirmation of it) is postmarked for
dispatch by first class, postage prepaid, United States mail.  These notice
provisions apply only if a notice is required by this Note.  They do not apply
if no notice is required.  This Note is not assignable by Maker.

DIGITAL LIGHTWAVE, INC.

By:_________________________

Name:_______________________

Title:________________________

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

STATE OF __________________

COUNTY OF ________________

The foregoing instrument was acknowledged before me this ____ day of _________,
2003, by ____________________________, as _____________________ of Digital
Lightwave, on behalf of the corporation.  He/she is personally known to me or
he/she has produced __________________ as identification.

__________________________________

Notary Public, State at Large