Exhibit 10.50

                               FOURTH AMENDMENT TO
                      AMENDED AND RESTATED CREDIT AGREEMENT


     THIS  FOURTH  AMENDMENT  TO AMENDED AND  RESTATED  CREDIT  AGREEMENT  (this
"AMENDMENT")  is made  and  entered  into as of March 4,  2002,  between  VODAVI
COMMUNICATIONS  SYSTEMS, INC.  ("BORROWER"),  the other Credit Parties signatory
thereto,  and  GENERAL  ELECTRIC  CAPITAL  CORPORATION,  a Delaware  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 and restated as of June 11,
1997, and as further  amended by (x) that certain First Amendment to Amended and
Restated  Credit  Agreement,  dated as of September  30, 1999,  (y) that certain
Second Amendment to Amended and Restated Credit  Agreement,  dated as of October
31, 1999,  and (z) that certain Third  Amendment to Amended and Restated  Credit
Agreement,  dated as of July, 2001 (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 a certain
Revolving  Credit  Loan to the  Borrower,  subject to the terms,  covenants  and
conditions contained in the Credit Agreement;

     WHEREAS,  the  Borrower  has  requested  that  the  Lender  consent  to its
formation of Vodavi Direct,  Inc. ("VDI") as a wholly-owned  subsidiary  through
which it will  acquire  all or  substantially  all of the  assets  of  Dataspeak
Systems, Inc. (the "ACQUISITION"); and

     WHEREAS, as a condition of Lender's consent to the Acquisition,  Lender has
requested, among other things, that (x) VDI be added as a Credit Party under the
Credit  Agreement  and (y) the Credit  Agreement  to be  modified  as  described
herein, and the Borrower and VDI are 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. VDI DEEMED TO BE A CREDIT  PARTY.  At all times on and after the date of
this  Amendment,  VDI  shall be  deemed to be a Credit  Party  under the  Credit
Agreement  and each of the other Loan  Documents  for all purposes of any nature
whatsoever.

     2. AMENDMENTS.

     (a) Section 1.1 of the Credit  Agreement is hereby amended by replacing the
definition of "Credit Parties" with the following:

          "CREDIT PARTIES" shall mean the Borrower, ESI and VDI, and
<PAGE>
          "CREDIT PARTY" shall mean any of the foregoing.

     (b) Section 1.1 of the Credit  Agreement is hereby amended by replacing the
definition of "ESI" with the following:

          "ESI" shall mean  Vodavi-CT,  Inc.,  an Arizona  corporation  formerly
          known as Enhanced Systems, Inc.

     (c) Section 1.1 of the Credit  Agreement is hereby amended by replacing the
definition of "Guaranty Agreement" with the following:

          "GUARANTY  AGREEMENT"  shall mean the Guaranty  Agreement from ESI and
          VDI to Lender in substantially the form of Exhibit O hereto,  pursuant
          to which ESI and VDI shall jointly and severally guarantee payment and
          performance of the Obligations.

     (d) Section 1.1 of the Credit  Agreement is hereby amended by replacing the
definition of "Security Agreements" with the following:

          "SECURITY   AGREEMENTS"   shall  mean,   collectively,   the  Security
          Agreements  entered into between Lender and each of Borrower,  ESI and
          VDI, respectively, in substantially the form of Exhibit D hereto.

     (e) Section  1.1 of the Credit  Agreement  is hereby  amended by adding the
following definition of "VDI":

          "VDI" shall mean Vodavi  Direct,  Inc., an Arizona  corporation  and a
          wholly-owned subsidiary of Borrower.

     (f) Section  9.10(b) of the Credit  Agreement is hereby amended by deleting
such section in its entirety and substituting the following in lieu thereof:

          (b)  If to Borrower, at:

               Vodavi Communication Systems, Inc.
               4717 E. Hilton Avenue
               Suite 400
               Phoenix, Arizona  85034
               Attn:  Mr. David Husband
               Telecopy No.: 480-483-0144

                                       2
<PAGE>
               With copies to:

               Greenberg Traurig
               2375 East Camelback Road
               Suite 700
               Phoenix, Arizona  85016
               Attn:  Karl A. Freeburg, Esq.
               Telecopy No.: 602-445-8100

     3.  CONSENT TO  ACQUISITION  & INVENTORY  APPRAISAL.  Without  limiting the
applicability of Section 9.2 of the Credit Agreement, the Borrower hereby agrees
to reimburse the Lender on demand for all reasonable costs and expenses incurred
by the  Lender  in  connection  with its  consent  to the  Acquisition  and this
Amendment.

     4.  REPRESENTATIONS AND WARRANTIES.  Each of Borrower,  VDI and each of the
other Credit Parties hereby  represents and warrants to the Lender that (a) this
Amendment has been duly authorized,  executed and delivered by the Borrower, VDI
and each of the other  Credit  Parties,  (b) no Default or Event of Default  has
occurred and is continuing as of this date, and (c) each of the  representations
and warranties of the Borrower, VDI and each of the other Credit Parties made in
or pursuant to this  Amendment and the other Loan Documents is true and correct,
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.  Any breach by the Borrower,  VDI or any of the other
Credit Parties of its representations and warranties contained in this Section 4
shall be an Event of Default for all purposes of the Credit Agreement.

     5. RATIFICATION. Each of Borrower, VDI and each of the other Credit Parties
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 or any of the other Credit Parties is a party or to which VDI becomes a
party contemporaneously herewith), effective as of the date hereof.

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

     7. CONDITIONS TO EFFECTIVENESS.  The amendments contained in Sections 1 and
2 shall become  effective  retroactive to the date as of which this Amendment is
dated, subject to the satisfaction of the following conditions:

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

                                       3
<PAGE>
     (b)  the  receipt  by the  Lender  of a  certificate  signed  by the  chief
financial  officer or treasurer of the Borrower on behalf 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 Loan
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; and

     (c) the receipt by the Lender of each of the documents  listed below,  duly
executed,  completed  and  delivered  by the Lender,  the Borrower and the other
Credit Parties, as applicable:

          (i) Amended and Restated Stock Pledge and Security Agreement of Parent
     (including stock certificates and related stock powers);

          (ii) Stock Pledge and Security Agreement of Borrower  (including stock
     certificates and related stock powers);

          (iii) Amended and Restated Security Agreement of Borrower;

          (iv) Amended and Restated Security Agreement of ESI;

          (v) Security Agreement of VDI; and

          (vi) First Amendment to Guaranty.

     8.  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.

     9.  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
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,  each of Borrower  and each Credit  Party hereby
waives any provision of law that renders any provision  hereof  unenforceable in
any respect.

     10.  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.

     11. 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.

                                       4
<PAGE>
     IN WITNESS WHEREOF, the parties hereto have caused this Fourth Amendment to
Amended and Restated  Credit  Agreement to be duly executed by their  respective
duly authorized officers, as of the date first above written.

                                    VODAVI COMMUNICATIONS
                                    SYSTEMS, INC., AS BORROWER


                                    By: /s/ Gregory K. Roeper
                                        ----------------------------------------
                                    Name: Gregory K. Roeper
                                          --------------------------------------
                                    Title: President and CEO
                                           -------------------------------------


                                    GENERAL ELECTRIC CAPITAL
                                    CORPORATION, AS LENDER


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


                                    CREDIT PARTIES:


                                    VODAVI DIRECT, INC.


                                    By: /s/ Gregory K. Roeper
                                        ----------------------------------------
                                    Name: Gregory K. Roeper
                                          --------------------------------------
                                    Title: CEO
                                           -------------------------------------


                                    VODAVI-CT, INC.


                                    By: /s/ Gregory K. Roeper
                                        ----------------------------------------
                                    Name: Gregory K. Roeper
                                          --------------------------------------
                                    Title: CEO
                                           -------------------------------------


                                    VODAVI TECHNOLOGY, INC.


                                    By: /s/ Gregory K. Roeper
                                        ----------------------------------------
                                    Name: Gregory K. Roeper
                                          --------------------------------------
                                    Title: President and CEO
                                           -------------------------------------

                                       5