<PAGE>

                                                                   EXHIBIT 10.5

                       * CONFIDENTIAL TREATMENT REQUESTED
          CONFIDENTIAL PORTIONS HAVE BEEN OMITTED AND FILED SEPARATELY

                           AMENDMENT NO. 3 TO THE FIRST
                      AMENDED AND RESTATED CREDIT AGREEMENT
                                       AND
                      AMENDMENT NO. 5 TO THE ARCH GUARANTY

     AMENDMENT NO. 3 (the "CREDIT  AGREEMENT  AMENDMENT"),  dated as of March 9,
1998, to the First Amended and Restated Credit Agreement,  dated as of March 19,
1997, by and among USA Mobile Communications,  Inc. II (the "PARENT"),  Premiere
Page of Kansas, Inc. ("PREMIERE PAGE"), Q Media  Paging-Alabama,  Inc. ("Q MEDIA
ALABAMA"),   USA  Mobile   Communications,   Inc.  III  ("USA  III"),   Q  Media
Company-Paging,  Inc.  ("Q MEDIA  KANSAS"),  W.Q.  Communications,  Inc.  ("W.Q.
COMMUNICATIONS", and together with Premiere Page, Q Media Alabama, USA III and Q
Media Kansas,  the "BORROWERS",  each a "BORROWER"),  the Lenders party thereto,
and The Bank of New York, as Administrative Agent (the "ADMINISTRATIVE  AGENT"),
as amended by Amendment  No. 1, dated as of June 17, 1997,  and Amendment No. 2,
dated as of January 7, 1998 (as amended, the "CREDIT AGREEMENT"); and

     AMENDMENT  NO. 5 (the "ARCH  GUARANTY  AMENDMENT"  and,  together  with the
Credit Agreement Amendment, this "AMENDMENT"), dated as of March 9, 1998, to the
Arch Guaranty,  Security and Subordination  Agreement,  dated as of September 8,
1995, made by Arch  Communications  Group, Inc. ("ARCH"),  the Borrowers and the
Parent to the  Administrative  Agent, as amended by Amendment No. 1, dated as of
February 15, 1996,  Amendment No. 2, dated as of June 25, 1996, Amendment No. 3,
dated as of March 19, 1997, and Amendment No. 4, dated as of January 7, 1998 (as
so amended and as from time to time amended  supplemented or otherwise  modified
from time to time the "GUARANTY").

                                    RECITALS

     A.  Capitalized  terms used herein which are not herein  defined shall have
the respective meanings ascribed thereto in the Credit Agreement.

     B. The Parent and the  Borrowers  have  requested  that the  Administrative
Agent and the Lenders amend the Credit  Agreement and the Guaranty to the extent
and in the  manner  set forth  below and the  Administrative  Agent and  Lenders
executing  this  Amendment  are  willing  to do so  subject  to  the  terms  and
conditions of this Amendment.

     Accordingly,  in consideration of the covenants,  conditions and agreements
hereinafter  set  forth,  and for other  good and  valuable  consideration,  the
receipt and adequacy of which are hereby acknowledged,  the parties hereto agree
as follows:

     1.  The  following  definition  contained  in  Section  1.1 of  the  Credit
Agreement is amended and restated to read as follows:

               "ARCH  CREDIT  AGREEMENT":   the  First  Amended  and
          Restated  Credit  Agreement,  dated as of May 21, 1996, by
          and among Arch  Enterprises,  Arch, the Arch Lenders,  the
          Co-Agents party thereto, and the Arch Agent, as amended


<PAGE>




                       * CONFIDENTIAL TREATMENT REQUESTED
          CONFIDENTIAL PORTIONS HAVE BEEN OMITTED AND FILED SEPARATELY


          by Amendment No. 1, dated as of June 25, 1996, Amend- ment
          No. 2, dated as of March 25, 1997,  Amendment No. 3, dated
          as of June 17, 1997,  Amendment No. 4, dated as of January
          7, 1998, and Amendment No. 5 and Waiver No. 1, dated as of
          March 9,  1998,  and as the same may be  further  amended,
          modified or otherwise supplemented from time to time.

     2. Section 7.15 of the Credit  Agreement is amended in its entirety to read
as follows:

               7.15. LEVERAGE RATIO.

               Maintain,  or cause to be  maintained,  at all  times
          during the periods set forth  below,  a Leverage  Ratio of
          not greater than the ratios set forth below:

               PERIODS                             RATIO

               Restatement Effective
               Date through
               December 30, 1997                     *

               December 31, 1997 through
               December 30, 1998                     *

               December 31, 1998 through
               March 30, 1999                        *

               March 31, 1999 through
               December 30, 1999                     *

               December 31, 1999 and
               thereafter                            *.

               Notwithstanding the foregoing,  in the event that any
          Borrower makes a Restricted  Payment  permitted by Section
          8.5(a)(iv),  the maximum permitted Leverage Ratio shall be
          reduced for all periods after such payment to *.

     3.  Section  7.16(c) of the Credit  Agreement is amended in its entirety to
read as follows:

               (c) For purposes hereof "Triggering Event" shall mean
          the  determination  of  Minority  Lenders  to  direct  the
          Administrative   Agent  to  declare  any  or  all  of  the
          Collateral  Documents  effective  and to require  that the
          Restricted  Sub-  sidiaries from time to time grant to the
          Administrative  Agent  under  the  applicable   Collateral
          Document a first priority security interest in one or more
          items of  Collateral.  Such  determination  may be made by
          Minority Lenders in


                                - 2 -


<PAGE>


          their  sole  and  absolute  discretion  whether  or  not a
          Default  or  Event of  Default  has  occurred  and is then
          continuing.

     4.  All  references  in any Loan  Document to "Triggering  Event"  shall be
deemed to refer to such term as amended hereby.

     5.  Section 12 of the Arch  Guaranty is amended by deleting the phrase "the
Arch  Credit  Agreement  (without  giving  effect to any  amendment  (other than
Amendment No. 1,  Amendment No. 2,  Amendment No. 3 and Amendment No. 4), waiver
or termination thereof)" wherever it appears in such section and by substituting
the phrase "the Arch Credit  Agreement  (without  giving effect to any amendment
(other than  Amendment No. 1,  Amendment No. 2, Amendment No. 3, Amendment No. 4
and Amendment No. 5 and Waiver No. 1),  waiver or  termination  thereof)" in its
place.

     6.  Paragraphs 1-5 of this Amendment shall not be effective until the prior
or  simultaneous   fulfillment  of  the  following  conditions  (the  "AMENDMENT
EFFECTIVE DATE"):

          (a) The  Administrative  Agent  shall  have  received  this  Amendment
     executed by a duly  authorized  officer or officers of the  Borrowers,  the
     Parent,  the  Subsidiary  Guarantors,  the  Administrative  Agent  and  the
     Required Lenders.

          (b) The Administrative  Agent shall have received a certificate of the
     Secretary  or  Assistant  Secretary  of the  Parent and each  Borrower  (i)
     attaching  a true and  complete  copy of the  resolutions  of its  Managing
     Person  authorizing  this Amendment (in form and substance  satisfactory to
     the  Administrative   Agent),  (ii)  certifying  that  its  certificate  of
     incorporation  and by-laws have not been amended since March 19, 1997,  or,
     if so, setting forth the same and (iii) setting forth the incumbency of its
     officer  or  officers  who may sign  this  Amendment,  including  therein a
     signature specimen of such officer or officers.

     (c) The  Administrative  Agent  shall have  received a  certificate  of the
     Secretary or Assistant  Secretary of Arch (i) attaching a true and complete
     copy of the resolutions of its Managing Person  authorizing  this Amendment
     and Amendment No. 5 to the Arch First Amended and Restated Credit Agreement
     (in form and substance  satisfactory  to the  Administrative  Agent),  (ii)
     certifying that its certificate of incorporation  and by-laws have not been
     amended since March 19, 1997,  or, if so,  setting forth the same and (iii)
     setting  forth the  incumbency of its officer or officers who may sign this
     Amendment,  including  therein a  signature  specimen  of such  officer  or
     officers.

          (d) The  Administrative  Agent shall have received  Amendment No. 4 to
     the Arch First Amended and Restated Credit Agreement,  duly executed by the
     parties  necessary  thereto and in form and substance  satisfactory  to the
     Administrative Agent and the conditions to the effectiveness  thereof shall
     have been satisfied.

          (e) The  Administrative  Agent shall have  received for the account of
     each Lender  executing  this Amendment and Amendment No. 5 and Waiver No. 1
     to the Arch Credit Agreement, an amendment fee equal to 0.10% of the amount
     of such Lender's Commitment.

                                      - 3 -


<PAGE>



          (f) The  Administrative  Agent shall have  received an opinion of Hale
     and Dorr, counsel to the Parent, the Borrower, substantially in the form of
     Attachment A.

          (g) The  Administrative  Agent shall have received an opinion of Garry
     B. Watzke, Esq., General Counsel to Arch, and the Restricted  Subsidiaries,
     substantially in the form of Attachment B.

          (h) The reasonable  fees and expenses of Special  Counsel  incurred to
     the Amendment Effective Date shall have been paid.

          (i) The Administrative  Agent shall have received such other documents
     as it shall reasonably request.

     7. As of the date hereof and as of the Amendment  Effective Date, each Loan
Party hereby (a) reaffirms and admits the validity and enforceability of each of
the Loan Documents (as amended by this Amendment) to which it is a party and all
of its obligations thereunder,  (b) represents and warrants that there exists no
Default  or  Event  of  Default,  and  (c)  represents  and  warrants  that  the
representations  and  warranties  contained in the Loan Documents (as amended by
this  Amendment)  (other than the  representations  and warranties  made as of a
specific  date) are true and  correct in all  material  respects,  except to the
extent that such representations and warranties are no longer true or correct as
a result of events,  acts,  transactions  or occurrences  after the  Restatement
Effective Date which are permitted under the Credit Agreement.

     8. This  Amendment may be executed in any number of  counterparts,  each of
which shall be an original and all of which shall  constitute one amendment.  It
shall not be necessary  in making proof of this  Amendment to produce or account
for more than one counterpart signed by the party to be charged.

     9. This Amendment is being  delivered in and is intended to be performed in
the State of New York and shall be construed and enforceable in accordance with,
and be governed by, the internal laws of the State of New York without regard to
principles of conflict of laws.

     10. Except as amended  hereby,  the Credit  Agreement and the Arch Guaranty
shall in all other respects remain in full force and effect.

                                      - 4 -


<PAGE>


     IN WITNESS WHEREOF,  the parties hereto have caused this Amendment No. 3 to
the First Amended and Restated Credit  Agreement and Amendment No. 5 to the Arch
Guaranty, Security and Subordination Agreement to be duly executed and delivered
by their proper and duly authorized  officers as of the day and year first above
written.

                                     PREMIERE PAGE OF KANSAS, INC.,
                                     Q MEDIA PAGING-ALABAMA, INC.,
                                     USA MOBILE COMMUNICATIONS, INC. III,
                                     Q MEDIA COMPANY-PAGING, INC.,
                                      a Kansas corporation
                                     W.Q. COMMUNICATIONS, INC.

                                     AS TO EACH OF THE FOREGOING

                                     By:      /S/ GERALD J. CIMMINO
                                     Name: GERALD J. CIMMINO
                                     Title: VICE PRESIDENT AND TREASURER

                                     USA MOBILE COMMUNICATIONS, INC. II

                                     By:      /S/ GERALD J. CIMMINO
                                     Name: GERALD J. CIMMINO
                                     Title: VICE PRESIDENT AND TREASURER

                                     ARCH COMMUNICATIONS GROUP, INC.

                                     By:      /S/ GERALD J. CIMMINO
                                     Name: GERALD J. CIMMINO
                                     Title: VICE PRESIDENT AND TREASURER


<PAGE>


                        AMENDMENT NO. 3 TO THE USA MOBILE
                   FIRST AMENDED AND RESTATED CREDIT AGREEMENT
                                       AND
                      AMENDMENT NO. 5 TO THE ARCH GUARANTY

                                     THE BANK OF NEW YORK, individually and as
                                     Administrative Agent

                                     By:      /S/ GEOFFREY C. BROOKS
                                     Name: GEOFFREY C. BROOK
                                     Title:   VICE PRESIDENT


<PAGE>


                        AMENDMENT NO. 3 TO THE USA MOBILE
                   FIRST AMENDED AND RESTATED CREDIT AGREEMENT
                                       AND
                      AMENDMENT NO. 5 TO THE ARCH GUARANTY

                                     FLEET NATIONAL BANK

                                     By:      /S/ CHRIS SWINDELL
                                     Name: CHRIS SWINDELL
                                     Title:   VICE PRESIDENT


<PAGE>


                        AMENDMENT NO. 3 TO THE USA MOBILE
                   FIRST AMENDED AND RESTATED CREDIT AGREEMENT
                                       AND
                      AMENDMENT NO. 5 TO THE ARCH GUARANTY

                                     PNC BANK, NATIONAL ASSOCIATION

                                     By:      /S/ JEFFREY E. HAUSER
                                     Name: JEFFREY E. HAUSER
                                     Title:   VICE PRESIDENT


<PAGE>


                        AMENDMENT NO. 3 TO THE USA MOBILE
                   FIRST AMENDED AND RESTATED CREDIT AGREEMENT
                                       AND
                      AMENDMENT NO. 5 TO THE ARCH GUARANTY

                                     TORONTO DOMINION (TEXAS), INC.

                                     By:      /S/ DEBBIE A. GREENE
                                     Name: DEBBIE A. GREENE
                                     Title:   VICE PRESIDENT


<PAGE>


                        AMENDMENT NO. 3 TO THE USA MOBILE
                   FIRST AMENDED AND RESTATED CREDIT AGREEMENT
                                       AND
                      AMENDMENT NO. 5 TO THE ARCH GUARANTY

                                     BANKBOSTON, N.A.

                                     By:      /S/ SHEPARD D. RAINIE
                                     Name: SHEPARD D. RAINIE
                                     Title:   DIRECTOR


<PAGE>


                        AMENDMENT NO. 3 TO THE USA MOBILE
                   FIRST AMENDED AND RESTATED CREDIT AGREEMENT
                                       AND
                      AMENDMENT NO. 5 TO THE ARCH GUARANTY

                                     ROYAL BANK OF CANADA

                                     By:      /S/ THOMAS BYRNE
                                     Name: THOMAS BYRNE
                                     Title:


<PAGE>


                        AMENDMENT NO. 3 TO THE USA MOBILE
                   FIRST AMENDED AND RESTATED CREDIT AGREEMENT
                                       AND
                      AMENDMENT NO. 5 TO THE ARCH GUARANTY

                                     SUNTRUST BANK, CENTRAL FLORIDA, N.A.

                                     By:      /S/ MICHAEL R. BUTLER
                                     Name: MICHAEL R. BUTLER
                                     Title:   SENIOR VICE PRESIDENT


<PAGE>


                        AMENDMENT NO. 3 TO THE USA MOBILE
                   FIRST AMENDED AND RESTATED CREDIT AGREEMENT
                                       AND
                      AMENDMENT NO. 5 TO THE ARCH GUARANTY

                                     VAN KAMPEN AMERICAN CAPITAL PRIME
                                     RATE INCOME TRUST

                                     By:      /S/ JEFFREY W. MAILLET
                                     Name: JEFFREY W. MAILLET
                                     Title:   SENIOR VICE PRESIDENT & DIRECTOR


<PAGE>


                        AMENDMENT NO. 3 TO THE USA MOBILE
                   FIRST AMENDED AND RESTATED CREDIT AGREEMENT
                                       AND
                      AMENDMENT NO. 5 TO THE ARCH GUARANTY

         By signing below, each of the Subsidiary Guarantors agrees and consents
to the foregoing Amendment

PCI HOLDING COMPANY, INC.
PROFESSIONAL COMMUNICATIONS, INC.
PROFESSIONAL ELECTRONICS, INC.
Q MEDIA COMPANY-PAGING, INC.,
  a Delaware corporation

AS TO EACH OF THE FOREGOING:

By:      /S/ GERALD J. CIMMINO
Name:    GERALD J. CIMMINO
Title:   VICE PRESIDENT AND TREASURER


<PAGE>


                                                           Attachment A

        FORM OF OPINION OF COUNSEL TO ARCH, THE PARENT AND THE BORROWERS

                                           March __, 1998

The Bank of New York,
as Administrative Agent, and the
Lenders under the Amended
Agreement referred to below

     We have acted as special counsel to (i) USA Mobile Communications, Inc. II,
a Delaware  corporation  (the "PARENT"),  (ii) Premiere Page of Kansas,  Inc., a
Kansas corporation  ("PREMIERE  PAGE"),  (iii) Q Media  Paging-Alabama,  Inc., a
Delaware corporation ("Q MEDIA ALABAMA"),  (iv) USA Mobile Communications,  Inc.
III, a Delaware  corporation  ("USA III"), (v) Q Media  Company-Paging,  Inc., a
Kansas corporation ("Q MEDIA KANSAS"), (vi) W.Q. Communications,  Inc., a Kansas
corporation  ("W.Q.  COMMUNICATIONS",  and together with Premiere  Page, Q Media
Alabama,  USA III and Q Media Kansas,  the  "BORROWERS",  each a "BORROWER") and
(vii) Arch  Communications  Group,  Inc.,  a Delaware  corporation  ("ARCH" and,
together with the Borrowers and the Parent, the  "CORPORATIONS"),  in connection
with Amendment No. 3 (the "CREDIT  AGREEMENT  AMENDMENT"),  dated as of March 9,
1998, to the First Amended and Restated Credit Agreement,  dated as of March 19,
1997, by and among the Parent, the Borrowers, the Lenders party thereto, and The
Bank of New York,  as  Administrative  Agent (the  "ADMINISTRATIVE  AGENT"),  as
amended by Amendment  No. 1, dated as of June 17,  1997,  and  Amendment  No. 2,
dated as of  January  7,  1998 (as so  amended,  the  "CREDIT  AGREEMENT"),  and
Amendment No. 5 (the "ARCH  GUARANTY  AMENDMENT"  and,  together with the Credit
Agreement Amendment,  the "AMENDMENT"),  dated as of March __, 1998, to the Arch
Guaranty,  Security and Subordination Agreement,  dated as of September 8, 1995,
made by Arch,  the  Borrowers  and the Parent to the  Administrative  Agent,  as
amended by  Amendment  No. 1, dated as of February 15,  1996,  Amendment  No. 2,
dated as of June 25,  1996,  Amendment  No. 3, dated as of March 19,  1997,  and
Amendment  No. 4, dated as of January 7, 1998 (as so amended,  the  "GUARANTY").
The Credit Agreement and the Guaranty, as amended by the Amendment, are referred
to  collectively  herein as the  "AMENDED  AGREEMENTS".  Capitalized  terms used
herein and not otherwise defined herein shall have the meanings ascribed to them
in the Amended Agreements.

     For purposes of the opinions expressed below, we have examined:

     (a)  the Credit Agreement and the Guaranty;

     (b)  the Amendment;

     (c)  the charter  documents of each of the  Corporations  as  identified on
          Schedule I;

     (d)  the  By-laws  of each of the  Corporations,  as in  effect on the date
          hereof, provided to us by the Parent;


<PAGE>


     (e)  the corporate minute books of each of the Corporations, as provided to
          us by the Parent;

     (f)  certificates  of legal  existence and corporate  good standing for the
          Corporations as identified on Schedule II;

     (g)  certified  copies of  resolutions of the board of directors of each of
          the  Corporations,  approving  the  transactions  contemplated  by the
          Amendment and authorizing, among other things, the execution, delivery
          and performance by each of the Corporations of the Amendment;

     (h)  incumbency  and signature  certificates  as to the officers of each of
          the Corporations;

     (i)  a certificate of Garry Watzke,  Secretary of the Corporations,  in the
          form attached hereto as Exhibit A; and

     (j)  such other documents, instruments and certificates (including, but not
          limited  to,  certificates  of public  officials  and  officers of the
          Corporations)  as we have  considered  necessary  for purposes of this
          opinion.

     In addition,  we assume,  for purposes of this opinion,  that the corporate
minute books (referred to in clause (e) above) contain an accurate record of all
meetings of the stockholders and directors of the Corporations. In examining the
documents  described  above,  we have assumed the  genuineness of all signatures
other than those of the Corporations, the legal capacity of natural persons, the
authenticity of all documents submitted to us as originals and the conformity to
the  originals of all documents  submitted to us as copies.  As to various facts
material  to the  opinions  set  forth  herein,  we  have  relied  upon  factual
representations  made by the  Corporations  in the  Amended  Agreements  and the
Amendment,  in  the  certificate  referred  to in  clause  (i)  above  and  upon
certificates  of  public  officials,  which  facts  we  have  not  independently
verified.

     Any  reference  to  "our  knowledge",   "the  best  of  our  knowledge"  or
"knowledge" or any variation  thereof shall mean the conscious  awareness of the
attorneys  in  this  firm  who  have  rendered  substantive  attention  to  this
transaction of the existence or absence of any facts which would  contradict our
opinions set forth below. We have not undertaken any  independent  investigation
to determine the existence or absence of such facts,  and no inference as to our
knowledge  of the  existence  or absence of such facts  should be drawn from the
fact of our representation of the Corporations.

     For purposes of the  opinions  expressed  herein,  we have assumed that the
Administrative  Agent and the Lenders  have the power and  authority to execute,
deliver and perform all  agreements  and  documents  executed by them;  that the
Administrative  Agent  and the  Lenders  have  duly  and  validly  executed  and
delivered such agreements and documents;  and that such agreements and documents
are legally  valid and  binding on and  enforceable  against the  Administrative
Agent and the Lenders.

     We  express  no  opinion  herein  with  respect to the laws of any state or
jurisdiction   other  than  the  Commonwealth  of  Massachusetts,   the  General
Corporation  Law  statute of the State of Delaware  and the federal  laws of the
United States of America. With your permission, we have

                                      - 2 -
<PAGE>

assumed,  without  investigation,  for purposes of the opinions  expressed below
that the laws of the Commonwealth of Massachusetts  are identical to the laws of
the State of New York.

     The opinions expressed in paragraph 1 below,  insofar as they relate to the
valid  existence  and  corporate  good  standing  of the  Corporations  in their
respective  states of  incorporation  are  based  solely  upon the  certificates
referred  to in  clause  (f)  above  and are  rendered  as of the  dates of such
certificates.

     Our  opinions  below are  qualified  to the  extent  that the  validity  or
enforceability  of the documents  referred to or of any of the rights granted to
any party  pursuant  thereto  may be subject to or  affected  by (i)  applicable
bankruptcy,  insolvency,  reorganization,  moratorium,  fraudulent conveyance or
similar laws  affecting  the rights of creditors  generally,  (ii)  statutory or
decisional  law  concerning  recourse by creditors to security in the absence of
notice or hearing,  and (iii)  duties and  standards  imposed on  creditors  and
parties to contracts, including, without limitation, requirements of good faith,
reasonableness  and fair dealing.  Furthermore,  we express no opinion as to the
availability  of any  equitable  or  specific  remedy  upon any  breach  of such
documents  or  any of the  agreements,  documents  or  obligations  referred  to
therein,  as the  availability of such remedies may be subject to the discretion
of a court.  We have  assumed for the  purposes of our opinion  that each of the
Lenders  and the  Administrative  Agent is subject  to  control,  regulation  or
examination by a state or federal regulatory agency.

     Based upon and subject to the foregoing  and to the general  qualifications
stated following paragraph 3 below, we hereby advise you that, in our opinion:

     1. Each of Arch, the Parent, Q Media Alabama, USA III, and Q Media Delaware
is duly organized,  validly  existing and in good standing under the laws of the
State of Delaware and is in good standing and  authorized to do business in each
jurisdiction  in which the  failure  to be so  authorized  could  reasonably  be
expected to have a Material Adverse Effect.

     2. Each of Premiere  Page, Q Media Kansas and W.Q.  Communications  is duly
organized,  validly existing and in good standing under the laws of the State of
Kansas  and  is  in  good  standing  and  authorized  to  do  business  in  each
jurisdiction  in which the  failure  to be so  authorized  could  reasonably  be
expected to have a Material Adverse Effect.

     3. No consent,  authorization  or approval of,  filing with,  notice to, or
exemption by,  stockholders,  any Governmental  Body or any other Person (except
for those which have been obtained, made or given) (i) is required to authorize,
or is required in connection  with, the execution,  delivery and  performance of
the  Amendment or the Amended  Agreements  or (ii) is required as a condition to
the validity or enforceability of the Amendment or the Amended Agreements.

     4. The  Amendment  and the  Amended  Agreements  constitute  the  valid and
legally  binding  obligations of each of the  Corporations,  in each case to the
extent that it is a party thereto, enforceable in accordance with its respective
terms.

     The opinions set forth above are subject to the following qualifications:

          (i) The enforcement  against any of the Corporations of any rights and
     remedies is or may be subject to the effect of certain  general  principles
     of contract law that include (a) the  unenforceability  of provisions in an
     agreement  to the effect  that  provisions  therein  may only be amended or
     waived in writing to the extent that an oral agreement modifying

                                      - 3 -
<PAGE>

     such provisions has been entered into and (b) the general rule that,  where
     less than all of an agreement is  enforceable,  the balance is  enforceable
     only when the unenforceable  portion is not an essential part of the agreed
     exchange.

          (ii) We express no opinion  as to the  enforceability  of  prospective
     waivers  of rights  to notice or a  hearing,  or other  rights  granted  by
     constitution  or statute,  powers of  attorney,  provisions  purporting  to
     relieve parties of the  consequences of their own negligence or misconduct,
     provisions  granting  indemnity  or  provisions   purporting  to  establish
     evidentiary standards.

          (iii)  All  opinions  expressed  above  are  subject  to  all  of  the
     qualifications  and  assumptions  contained  in our opinion  letter and our
     supplemental  opinion  letter,  each  dated  March  19,  1997  (the  "PRIOR
     OPINIONS").

     This opinion is based upon currently existing statutes,  rules, regulations
and  judicial  decisions,  and we disclaim any  obligation  to advise you of any
change  in  any  of  these  sources  of  law  or  subsequent  legal  or  factual
developments which might affect any matters or opinions set forth herein.

     We hereby confirm that each Lender under the Amended Agreements may rely on
the Prior Opinions as though such Prior Opinions were addressed to each of them.

     This opinion is furnished to you solely for your benefit in connection with
the Amendment and may not be relied upon by any other Person (other than Special
Counsel) or for any other purpose without our express, prior written consent.


                                        Very truly yours,

                                        HALE AND DORR



                                      - 4 -


<PAGE>


                                    EXHIBIT A

                              OFFICER'S CERTIFICATE


<PAGE>



                                   SCHEDULE I

                                CHARTER DOCUMENTS

I.    Arch Communications Group, Inc.        Certificate of Incorporation,
                                             State of Delaware

II.   USA Mobile Communications,
      Inc. II                                Certificate of Incorporation,
                                             State of Delaware

III.  Premiere Page of Kansas, Inc.          Certificate of Incorporation,
                                             State of Kansas

IV.   Q Media Paging - Alabama, Inc.         Certificate of Incorporation,
                                             State of Delaware

V.    USA Mobile Communications,
      Inc. II                                Certificate of Incorporation,
                                             State of Delaware

VI.   Q Media Company - Paging,
      Inc. (Kansas)                          Certificate of Incorporation,
                                             State of Kansas

VII.  W.Q. Communications,
      Inc.                                   Certificate of Incorporation,
                                             State of Kansas


<PAGE>



                                   SCHEDULE II

                 LEGAL EXISTENCE AND GOOD STANDING CERTIFICATES

I.   ARCH COMMUNICATIONS GROUP, INC.

     1.   Certificate  of Good Standing  signed by the Secretary of State of the
          State of Delaware dated ----- --, ----.

     2.   Certificate  of Good Standing  signed by the Secretary of State of the
          Commonwealth of Massachusetts dated _____ __, ____.

II.  USA Mobile Communications, Inc. II

     1.   Certificate  of Good Standing  signed by the Secretary of State of the
          Commonwealth of Pennsylvania dated March __, 1997.

     2.   Certificate of Existence/Authority signed by the Secretary of State of
          the State of Mississippi dated March __, 1997.

     3.   Certificate of Existence - Foreign Corporation signed by the Secretary
          of State of the State of Georgia dated March __, 1997.

     4.   Certificate of Corporate Good Standing - Foreign Corporation signed by
          the Secretary of State of the State of Missouri dated March __,1997.

     5.   Certificate  of Good Standing  signed by the Secretary of State of the
          State of Delaware dated March __, 1997.

     6.   Certificate  of Good Standing  signed by the Secretary of State of the
          State of Ohio dated March __, 1997.

     7.   Certificate of  Authorization  signed by the Secretary of State of the
          State of Indiana dated March __, 1997.

     8.   Certificate  of  Authorization  -  Foreign  Corporation  signed by the
          Secretary of State of the State of Kentucky dated March __, 1997.

     9.   Certificate of  Authorization  signed by the Secretary of State of the
          State of Tennessee dated March __, 1997.

III. USA Mobile Communications, Inc. III

     1.   Certificate  of Good Standing  signed by the Secretary of State of the
          State of Delaware dated March __, 1997.


<PAGE>


IV.  Premiere Page of Kansas, Inc.

     1.   Certificate of Authority - Foreign Corporation signed by the Secretary
          of State of the State of Nebraska for the entity "Premiere Page, Inc."
          dated March __, 1997.

     2.   Certificate  of Good Standing  signed by the Secretary of State of the
          State of Kansas dated March __, 1997.

     3.   Certificate of Existence signed by the Secretary of State of the State
          of Georgia dated March __, 1997.

     4.   Certificate  of Good  Standing  -  Foreign  Corporation  signed by the
          Secretary of State of the State of Missouri dated March __, 1997.

V.   Q Media Paging - Company, Inc., a Kansas corporation

     1.   Certificate  of Good Standing  signed by the Secretary of State of the
          State of Kansas dated March __, 1997.

     2.   Certificate  of Good  Standing  -  Foreign  Corporation  signed by the
          Secretary of State of the State of Illinois dated March __, 1997.

     3.   Certificate of  Authorization  signed by the Secretary of State of the
          State of Indiana dated March __, 1997.

     4.   Certificate of  Authorization  signed by the Secretary of State of the
          State of Iowa dated March __, 1997.

     5.   Certificate  of  Authorization  -  Foreign  Corporation  signed by the
          Secretary of State of the State of Kentucky dated March __, 1997.

     6.   Certificate of Corporate Good Standing - Foreign Corporation signed by
          the Secretary of State of the State of Missouri dated March __, 1997.

     7.   Certificate  of Good Standing  signed by the Secretary of State of the
          State of Delaware dated March __, 1997.

VI.  Q Media Paging - Alabama, Inc.

     1.   Certificate  of Good  Standing  -  Foreign  Corporation  signed by the
          Secretary of State of the State of Alabama dated March __, 1997.

     2.   Certificate  of Good Standing  signed by the Secretary of State of the
          State of Tennessee dated March __, 1997.

     3.   Certificate of Existence - Foreign Corporation signed by the Secretary
          of State of the State of Georgia dated March __, 1997.


<PAGE>


     4.   Certificate  of Good Standing  signed by the Secretary of State of the
          State of Delaware dated March __, 1997.

VII. W.Q. Communications, Inc.

     1.   Certificate  of Good Standing  signed by the Secretary of State of the
          State of Kansas dated March __, 1997.

     2.   Certificate of Corporate Good Standing - Foreign Corporation signed by
          the Secretary of State of the State of Missouri dated March __,1997.

     3.   Certificate of Existence - Foreign Corporation signed by the Secretary
          of State of the State of Georgia dated March __, 1997.


<PAGE>


                                                      Attachment B

                   FORM OF OPINION OF GENERAL COUNSEL OF ARCH
                         AND THE RESTRICTED SUBSIDIARIES

                                        March __, 1998

The Bank of New York,
as Administrative Agent, and the
Lenders under the Amended
Agreement referred to below

     I have acted as special counsel to (i) USA Mobile Communications,  Inc. II,
a Delaware  corporation  (the "PARENT"),  (ii) Premiere Page of Kansas,  Inc., a
Kansas corporation  ("PREMIERE  PAGE"),  (iii) Q Media  Paging-Alabama,  Inc., a
Delaware corporation ("Q MEDIA ALABAMA"),  (iv) USA Mobile Communications,  Inc.
III, a Delaware  corporation  ("USA III"), (v) Q Media  Company-Paging,  Inc., a
Kansas corporation ("Q MEDIA KANSAS"), (vi) W.Q. Communications,  Inc., a Kansas
corporation  ("W.Q.  COMMUNICATIONS",  and together with Premiere  Page, Q Media
Alabama,  USA III and Q Media Kansas,  the  "BORROWERS",  each a "BORROWER") and
(vii) Arch  Communications  Group,  Inc.,  a Delaware  corporation  ("ARCH" and,
together with the Borrowers and the Parent, the  "CORPORATIONS"),  in connection
with Amendment No. 3 (the "CREDIT  AGREEMENT  AMENDMENT"),  dated as of March 9,
1998, to the First Amended and Restated Credit Agreement,  dated as of March 19,
1997, by and among the Parent, the Borrowers, the Lenders party thereto, and The
Bank of New York,  as  Administrative  Agent (the  "ADMINISTRATIVE  AGENT"),  as
amended by Amendment  No. 1, dated as of June 17,  1997,  and  Amendment  No. 2,
dated as of  January  7,  1998 (as so  amended,  the  "CREDIT  AGREEMENT"),  and
Amendment No. 5 (the "ARCH  GUARANTY  AMENDMENT"  and,  together with the Credit
Agreement Amendment,  the "AMENDMENT"),  dated as of March __, 1998, to the Arch
Guaranty,  Security and Subordination Agreement,  dated as of September 8, 1995,
made by Arch,  the  Borrowers  and the Parent to the  Administrative  Agent,  as
amended by  Amendment  No. 1, dated as of February 15,  1996,  Amendment  No. 2,
dated as of June 25,  1996,  Amendment  No. 3, dated as of March 19,  1997,  and
Amendment  No. 4, dated as of January 7, 1998 (as so amended,  the  "GUARANTY").
The Credit Agreement and the Guaranty, as amended by the Amendment, are referred
to  collectively  herein as the  "AMENDED  AGREEMENTS".  Capitalized  terms used
herein and not otherwise defined herein shall have the meanings ascribed to them
in the Amended Agreements.

     In  connection  with this  opinion,  I have  examined and am familiar  with
originals or copies,  certified or otherwise  identified to my  satisfaction  as
being true copies, of all such records of the Corporations, such certificates of
the officers of the Corporations, all such agreements and other documents of the
Corporations,   including,   without   limitation,   (i)  the   Certificate   of
Incorporation  and By-laws of each of the  Corporations,  (ii)  certificates  of
public  officials,  and (iii) the Amendment,  and have made such other inquiries
and  investigations  of law, as I have deemed  necessary or appropriate  for the
purposes of rendering this opinion.


<PAGE>


     In rendering this opinion, I have assumed the genuineness of all signatures
(other  than  those of the  Corporations),  the  authenticity  of all  documents
submitted to me as originals, the conformity to original documents of all copies
submitted to me as certified  or  photostatic  copies and the accuracy of public
records.

     I am a member of the Bar of the  Commonwealth  of  Massachusetts.  I do not
purport to be an expert in, or to express  any opinion  concerning,  any matters
governed by the laws of any jurisdiction other than the laws of the Commonwealth
of Massachusetts and the corporate laws of the States of New York, Pennsylvania,
Kansas and  Delaware  and the federal  laws of the United  States of America.  I
express no opinion with  respect to the  regulation  of any of the  Corporations
under  the  Communications  Act  and  the  rules  and  regulations   promulgated
thereunder.

     On  the  basis  of  the   foregoing,   and  subject  to  the   limitations,
qualifications and exceptions set forth herein, I am of the opinion that each of
the Corporations  has full corporate power and authority to enter into,  execute
and deliver the  Amendment and to carry out the terms of the  Amendment,  all of
which have been duly authorized by all proper and necessary corporate action and
are in full compliance with its charter documents and by-laws.

     This  opinion is solely for your  benefit and that of your  successors  and
assigns  and may not be  relied  on by any  other  Person,  other  than  Special
Counsel,  without my prior written consent, and I assume no obligation to advise
of any  change in  matters of fact or of law which  might  change  the  opinions
expressed herein.

                                          Very truly yours,

                                          Garry B. Watzke, Esq.



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