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                                                                  EXHIBIT 10.22


March 31, 1999



Mr. Gerry Chastelet, President
Mr. Steve Grant, CFO
Digital Lightwave, Inc.
15550 Lightwave Drive
Clearwater, FL  33760


Gentlemen:

This Letter of Commitment shall set forth the terms and conditions under which
Emergent Asset Based Lending, LLC. d/b/a Emergent Business Capital (the
"Lender") will extend a line of credit (the "Line of Credit") to Borrower (as
defined below). The terms and conditions are as follows:

         1.       Borrower:         Digital Lightwave, Inc.

         2.       Line of Credit:   No more than Five Million Dollars
                  ($5,000,000), hereinafter the Line of Credit. Subject to
                  obtaining a suitable participant in this transaction, the line
                  amount may be increased to $7,000,000. The suitability of the
                  participant shall be determined by the Lender in its sole
                  discretion.

         3.       Type of Line and Purpose:   To be used for working capital.

         4.       Term:             Two-Year Contract which will automatically 
                  renew unless terminated by 60-days notice prior to the
                  expiration date.

         5.       Interest Rate:    One and one-half percentage points (1.50%)
                  above the Prime Rate as determined by Summit Bank, based on
                  the daily unpaid principal balance of advances.


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         6.       Collateral:       A first lien on all of Borrower's personal
                  property including, but not limited to accounts receivable,
                  inventory, equipment, fixtures, instruments, documents and
                  chattel paper, general intangibles, patents and trademarks,
                  and books and records relating thereto.

         7.       *Commitment Fee and Line Fee:   The Borrower agrees to pay to
                  Lender a fee equal to a half one percent (.50%) of the total
                  line which shall constitute a Commitment Fee in the amount of
                  Twenty Five Thousand Dollars ($25,000) which is deemed earned
                  and nonrefundable upon acceptance of this Commitment Letter by
                  Borrower. A Line Fee of Twenty Five Thousand Dollars ($25,000)
                  shall be due and payable at closing and each year at the
                  anniversary date of the facility provided. The aforesaid Line
                  Fee shall be due and payable whether or not the Loan
                  contemplated herein closes unless the failure to close is due
                  solely to Lender's gross negligence or willful misconduct.
                  This section and the obligations described herein are
                  independent of all other obligations set forth herein and
                  shall survive the expiration or termination of this Commitment
                  Letter and shall be payable in accord with this section.

         8.       Prepayment Fee:   The Borrower may prepay the line of credit 
                  by providing Emergent with 30-day written notice and payment
                  of a prepayment fee of 1% of the commitment amount if
                  terminated within the first twelve months of the contract and
                  .50% of the commitment amount if terminated within the second
                  twelve months of the contract.

         9.       Other Fees:       Monthly service fee (for each month or 
                  fraction thereof the Agreement is in effect) of three-quarters
                  of one percent (.75%) on the average daily balance of funds
                  employed. Audit fees of $500 per day plus out-of-pocket
                  expenses based on a 90-day cycle. Float days of one (1)
                  business day, all cash receipts will be directed to a lock-box
                  account for the benefit of the Borrower which will be swept
                  daily by Lender, and credited to the loan balance subject to
                  the float days indicated. Returned item fees and bank service
                  charges as levied by the depository banking institution. There
                  shall be a returned item fee of $5.00 per item above the cost
                  assessed to EBC. Wire fees of $10.00 per wire.

         10.      Closings Costs:   All closing costs, legal expenses and loan
                  documentation charges will be borne by Borrower but shall not
                  exceed $5,000. If this facility has not closed and an initial
                  disbursement made by April 15, 1999, this Commitment Letter
                  will be deemed to be of no force and effect.

-    An additional .50% each for the commitment fee and the line fee will be
     assessed against any increases provided in the Line of Credit facility.


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         11.      Guarantee:        A validity guarantee will be executed by 
                  senior management of Borrower, including the chairman,
                  president and chief financial officer.

         12.      Insurance:        Borrower shall furnish evidence, prior to 
                  the disbursement of any loan proceeds, of the appropriate
                  hazard and liability insurance issued by an insurance company
                  satisfactory to Lender in form and content acceptable to
                  Lender. Said insurance shall be at all times equal to or
                  greater than the outstanding principal balance of the Loan.
                  All insurance policies required hereunder must designate
                  Lender as loss payee in form acceptable to Lender.

         13.      Loan Documents:   Borrower and Guarantors shall sign and/or
                  furnish all documents deemed necessary by Lender and its legal
                  counsel. All documents shall be in form and content reasonably
                  acceptable to Lender and its legal counsel and shall be
                  governed under the laws of the State of Georgia. Borrower
                  understands that the terms and conditions of the transactions
                  contemplated by the Commitment letter are not limited to those
                  set forth herein. Those matters that are not covered or made
                  clear herein are subject to mutual agreement of the parties
                  (it being understood that such terms and conditions will not
                  be inconsistent with the terms set forth herein) and will be
                  set forth in the Loan Documents.

         14.      Financing Terms:  Accounts receivable to be advanced at 80% of
                  eligible accounts receivable base as defined in the proposal
                  letter. In the event that Lender determines dilution exceeds
                  5% during the first 60 days of financing, Lender reserves the
                  right to reduce the advance rate to 75%. Inventory advance
                  rate of 50% against raw goods and finished products not to
                  exceed the lesser of $2,000,000 or 50% of the eligible
                  accounts receivable borrowing base. In addition to all
                  inventory of Borrower and proceeds thereof, all of the
                  outstanding indebtedness will be secured by a first priority
                  lien against all machinery, equipment, furniture, fixtures and
                  all other assets of Borrower.

         15.      Financial Covenants: In addition to the standard "Affirmative"
                  and "Negative" Loan Covenants as defined in Lender's standard
                  Loan and Security Agreement previously provided to Borrower,
                  other covenants will include:

                           -        Cash discounts to account debtors not to
                                    exceed 2.00%, 10 days.
                           -        Annual Financial Statement Timing and Form -
                                    as stated in Section 10.1(a) of the Loan and
                                    Security Agreement and annual presentation
                                    to the S.E.C.


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                           -        Monthly Interim Financial Statements Timing
                                    and Form - As stated in Section 10.1(a) of
                                    the Loan and Security Agreement and
                                    quarterly presentation per the S.E.C.
                           -        Terms of Sales - due dates no more than 30
                                    calendar days from the date of the invoice
                                    unless approved by Lender in writing.
                           -        Minimum Working Capital - not to fall below
                                    $1,000,000 after reducing liabilities for
                                    non-cash charges.
                           -        Minimum Tangible Net Worth - not to fall
                                    below $3,000,000 during the term of the
                                    Agreement or any extension thereof.
                           -        Permitted Borrowings - None, other than
                                    indebtedness owed to Lender and (i) the
                                    existing indebtedness for borrowed money as
                                    of the date of this Commitment Letter other
                                    than Bankers Capital (EAB Leasing) for which
                                    the proceeds of Lender's loan will repay and
                                    (ii) the permitted purchase money security
                                    interest in conjunction with permitted
                                    capital expenditures and (iii) any
                                    borrowings which would be subordinate in
                                    payment and security interest to that of
                                    Lender. Upon execution of this Commitment
                                    Letter by Borrower, Lender consents to
                                    Borrower executing and entering into a
                                    subordinated debt transaction for
                                    $3,000,000.
                           -        Permitted Investments - none, except for
                                    existing investments in marketable
                                    securities.
                           -        Permitted Guaranties - None
                           -        Maximum Lease Rentals - None, other than the
                                    existing lease rentals as of the date of
                                    this Commitment, plus any new indebtedness
                                    allowed in conjunction with permitted
                                    capital expenditures as defined herein.
                           -        Capital Expenditures - not to exceed
                                    $2,000,000 annually directly which up to
                                    $1,000,000 can be funded internally by
                                    Borrower with the remaining portion funded
                                    externally through capital leases.

         Borrower by acceptance of this Commitment Letter, agrees to indemnify
         and hold harmless Lender and its respective directors, officers,
         employees, agents, advisors, attorneys and consultants (each an
         Indemnified Party) from and against any and all losses, claims,
         damages, liabilities, costs and expenses, including all reasonable fees
         and disbursements of counsel which may be incurred by or asserted or
         awarded against any Indemnified Party in connection with or arising out
         of or by reason of the preparation of the defense of any investigation,
         litigation or proceeding, whether or not any Indemnified Party is a
         party thereto, related to or in connection with this proposal or any of
         the transactions contemplated hereby.


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         Borrower acknowledges that this Commitment is expressly subject to the
         absence of a material adverse change in the business, condition
         (financial or otherwise), operations, performance, properties or
         prospects of Borrower since December 31, 1998. Such adverse change
         shall be determined by Lender in its reasonable judgement. Borrower and
         Lender agree to use their best efforts to prepare and execute
         definitive agreements covering this line of credit and to close the
         transaction as soon as practical.

         If the foregoing is satisfactory to you, please indicate your
         acceptance thereof and your agreement to borrow the funds as set forth
         herein from Lender upon the terms and conditions contained herein by
         signing and returning the original Commitment Letter to Lender at the
         address indicated by 5:00pm on April 1, 1999. In the event that you
         fail to comply with the foregoing, this Commitment Letter will, at the
         option of Lender, be of no further force and effect. The undertakings
         of Lender set forth in this Commitment Letter cannot be accepted
         conditionally, and any such conditional acceptance or modification of
         this Commitment Letter will be deemed rejected and will terminate
         absolutely the undertakings made herein. This Commitment Letter is not
         assignable.

                                          Very truly yours,

                                          Emergent Asset Based Lending, LLC

                                          --------------------------------------
                                          By:  John F. Fox
                                          Its:
                                              ----------------------------------



         THE FOREGOING IS ACCEPTED THIS
         ________DAY OF _____________,19____

         Digital Lightwave, Inc.

         By: 
            --------------------------------

         Its:
             -------------------------------