FOURTH AMENDMENT TO CREDIT AGREEMENT

     THIS FOURTH  AMENDMENT  TO CREDIT  AGREEMENT  (this  "AMENDMENT")  made and
entered into as of September 30, 1999,  between VODAVI  COMMUNICATIONS  SYSTEMS,
INC.  ("BORROWER")  and  GENERAL  ELECTRIC  CAPITAL  CORPORATION,   a  New  York
corporation ("LENDER").

                              W I T N E S S E T H:

     WHEREAS,  the  Borrower  and  the  Lender  entered  into a  certain  Credit
Agreement,  dated as of April 11,  1994,  as amended  (the  "CREDIT  AGREEMENT";
capitalized  terms used herein and not otherwise  defined  herein shall have the
meanings given such terms in the Credit Agreement), whereby the Lender agreed to
make  certain  loans  to the  Borrower,  subject  to the  terms,  covenants  and
conditions contained in the Credit Agreement; and

     WHEREAS,  the  Borrower  has  requested  that the Lender  modify the Credit
Agreement to extend the maturity date of the Revolving Credit Facility, increase
the  Commitment,   increase  the  percentage  of  Eligible   Inventory  used  in
calculating  the  Borrowing  Base,  to reduce the Non-use Fee, and to change the
address of the Borrower for communications  under the Credit Agreement,  and the
Lender  is  willing  to  make  such  modifications,  subject  to the  terms  and
conditions of this Amendment;

     NOW,  THEREFORE,  in  consideration  of the premises  and mutual  covenants
herein  contained,  and other good and valuable  consideration,  the receipt and
sufficiency  of which are  hereby  acknowledged,  the  parties  hereto  agree as
follows:

     1. AMENDMENTS. (a) The definition of "BORROWING BASE" in Section 1.1 of the
Credit  Agreement  is  hereby  deleted  in  its  entirety  and  replaced  by the
following:

               "BORROWING  BASE"  shall mean at any time an amount not to exceed
          the sum of: (i) 85% of  Eligible  Accounts,  and (ii) up to the lesser
          of: (A) $6,000,000 and (B) not more than 65% of Eligible  Inventory in
          each case (Eligible  Accounts and Eligible  Inventory) as shown on the
          most recently  delivered  Borrowing Base Certificate  delivered by the
          Borrower,   less  such  additional   reserves  as  Lender  shall  deem
          reasonably necessary.

          (b)  The  definition  of  "MATURITY  DATE" in Section 1.1 of the
     Credit  Agreement  is hereby  deleted in its  entirety  and replaced by the
     following:
<PAGE>
               "MATURITY  DATE"  shall  mean the date that is the later of:  (i)
          April 11, 2003, and (ii) the date to which,  upon prior mutual written
          agreement of the Borrower and Lender,  the expiration of the Revolving
          Credit Facility has been extended.

          (c) Section  2.1(a) of the Credit  Agreement is hereby  deleted in its
     entirety and replaced by the following:

               (a) CREDIT.  Upon and subject to the terms and conditions hereof,
          Lender  agrees from time to time to make  available  by deposit to the
          Disbursement   Account  on  any  Business  Day  until  the  Commitment
          Termination  Date,  upon the  request of Borrower  therefor,  advances
          (each,  a  "REVOLVING   CREDIT   ADVANCE")  in  an  aggregate   amount
          outstanding  that,  when added to the  aggregate  balance of Letter of
          Credit  Obligations  then  outstanding,  shall not at any  given  time
          exceed the lesser of (the  "REVOLVING  CREDIT ADVANCE  AVAILABILITY"):
          (i)  $15,000,000,  as such  amount may be  terminated  pursuant to the
          terms of SECTION 2.5 OR 8.2 (the "COMMITMENT"), and (ii) the Borrowing
          Base.

          (d) Section  2.3(b) of the Credit  Agreement is hereby  deleted in its
     entirety and replaced by the following:

               (b) NON-USE FEE. As additional  compensation  for Lender's  costs
          and risks in making the  Commitment  available to  Borrower,  Borrower
          agrees to pay to Lender,  in arrears for the preceding  month,  on the
          first Business Day of each month prior to the  Commitment  Termination
          Date and on the  Commitment  Termination  Date,  a fee for  Borrower's
          non-use of the  Commitment  (the "NON-USE  FEE") in an amount equal to
          one eighth of one  percent  (0.125%)  per annum on the  average  daily
          Revolving Credit Commitment Availability.

          (e) The  address of the  Borrower  contained  in  Section  9.10 of the
     Credit  Agreement  is hereby  deleted in its  entirety  and replaced by the
     following:

                          Vodavi Communications Systems, Inc.
                          8300 East Raintree Drive
                          Scottsdale, Arizona  85260
                          Attention: Tammy Powers, Chief Financial Officer
                          Telecopy No.:  (480) 483-0144

     2.  REPRESENTATIONS  AND  WARRANTIES.  The Borrower  hereby  represents and
warrants  to the  Lender  that (a) this  Amendment  has  been  duly  authorized,
executed  and  delivered  by the  Borrower,  (b) no Default has  occurred and is
continuing as of this date, and (c) each of the  representations  and warranties
of the Borrower made in or pursuant to this  Amendment  and the other  Financing
Documents is true and correct, except to the extent that any such representation

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<PAGE>
or warranty  expressly relates to an earlier date and except for changes therein
expressly  permitted or expressly  contemplated  by the Credit  Agreement,  both
before and after giving effect to this Amendment.  Any breach by the Borrower of
its representations and warranties contained in this Section 2 shall be an Event
of Default for all purposes of the Credit Agreement.

     3. RATIFICATION.  The Borrower hereby ratifies and reaffirms each and every
term and  condition set forth in the Credit  Agreement  and all other  documents
delivered by the Borrower in connection  therewith (including without limitation
the other Loan Documents to which the Borrower is a party),  effective as of the
date hereof.

     4.  ESTOPPEL.  To induce  the  Lender to enter  into  this  Amendment,  the
Borrower  hereby  acknowledges  and agrees that,  as of the date  hereof,  there
exists no right of offset,  defense or  counterclaim in favor of the Borrower as
against the Lender with respect to the  obligations  of the  Borrower  under the
Credit  Agreement  or the other Loan  Documents,  either with or without  giving
effect to this Amendment.

     5. CONDITIONS TO EFFECTIVENESS. The Amendments contained in Section 1 shall
become effective upon the date of this Amendment, subject to the satisfaction of
the following conditions on or prior to such date:

     (a) the receipt by the Lender of this Amendment,  together with the Consent
attached  hereto,  duly  executed,  completed and  delivered by the Lender,  the
Borrower, and the other Credit Parties;

     (b)  the  receipt  by the  Lender  of a  certificate  signed  by the  chief
financial  officer or treasurer  of the  Borrower to the effect that,  as of the
date of this Amendment, (i) no Default shall have occurred and be continuing and
(ii) each of the representations and warranties of the Credit Parties made in or
pursuant to this Amendment and the other  Financing  Documents  executed by such
Person is true,  except to the extent that any such  representation  or warranty
expressly  relates to an earlier date and except for changes  therein  expressly
permitted or expressly  contemplated  by the Credit  Agreement,  both before and
after giving effect to this Amendment;

     (c) the  receipt by the Lender of such  other  documents  as the Lender may
reasonably request.

     6.  GOVERNING  LAW. THIS  AGREEMENT  SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK FOR CONTRACTS TO BE PERFORMED
ENTIRELY WITHIN SAID STATE.

     7.  SEVERABILITY  OF PROVISIONS.  Any provision of this Amendment  which is
prohibited by, or invalid under the Applicable Law of any jurisdiction  shall be
ineffective to the extent of such prohibition or invalidity in such jurisdiction

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<PAGE>
without  invalidating the remaining  provisions hereof or affecting the validity
or  enforceability  of such provision in any other  jurisdiction.  To the extent
permitted by Applicable  Law,  Borrower  hereby waives any provision of law that
renders any provision hereof unenforceable in any respect.

     8.  COUNTERPARTS.   This  Amendment  may  be  executed  in  any  number  of
counterparts,  all of which shall be deemed to  constitute  but one original and
shall be binding upon all parties, their successors and permitted assigns.

     9. ENTIRE  AGREEMENT.  The Credit  Agreement  as amended by this  Amendment
embodies the entire agreement between the parties hereto relating to the subject
matter  hereof  and  supersede  all  prior   agreements,   representations   and
understandings, if any, relating to the subject matter hereof.




                  [Remainder of Page Intentionally Left Blank]

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<PAGE>

     IN WITNESS  WHEREOF,  the parties  hereto have caused this  Amendment to be
duly executed by their respective duly authorized officers, as of the date first
above written.

                                              VODAVI COMMUNICATIONS
                                              SYSTEMS, INC.

                                              By: /s/ Tammy M. Powers
                                              Name: Tammy M. Powers
                                              Title: Chief Financial Officer

                                              GENERAL ELECTRIC CAPITAL
                                              CORPORATION

                                              By: /s/ Timothy J. Rafanello
                                              Name: Timothy J. Rafanello
                                              Title: Duly Authorized Signatory


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<PAGE>
                                    CONSENT

     The  undersigned  Credit  Party  hereby  acknowledges  and consents to, and
agrees to the terms of, the foregoing Fourth Amendment to Credit Agreement,  and
ratifies and confirms its obligations  under the Loan Documents,  as of the date
of the foregoing Amendment.

                                           ENHANCED SYSTEMS, INC.


                                           By: /s/ Tammy M. Powers
                                           Name: Tammy M. Powers
                                           Title: Chief Financial Officer



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