<PAGE>   1
                THIS WARRANT AND THE SHARES OF COMMON STOCK ISSUABLE UPON
                EXERCISE HEREOF HAVE NOT BEEN REGISTERED UNDER STATE OR FEDERAL
                SECURITIES LAWS AND MAY NOT BE OFFERED FOR SALE, SOLD, PLEDGED
                OR OTHERWISE TRANSFERRED IN A MANNER THAT WOULD VIOLATE THE
                REGISTRATION PROVISIONS OF FEDERAL OR STATE SECURITIES LAWS,
                SUCH COMPLIANCE TO BE EVIDENCED, IF REASONABLY REQUESTED BY THE
                ISSUER OF THIS WARRANT, BY AN OPINION OF COUNSEL OF THE HOLDER,
                CONCURRED IN BY COUNSEL FOR THE ISSUER, THAT NO VIOLATION OF
                SAID REGISTRATION PROVISIONS WOULD RESULT FROM THE PROPOSED
                TRANSFER.

                             STOCK PURCHASE WARRANT

                           MIDCOM COMMUNICATIONS INC.

                                  COMMON STOCK

                               Par Value $0.0001

Date of Issuance: March 13, 1997                             Certificate No. W-5
Expiration:    March 13, 2007

        FOR VALUE RECEIVED, MIDCOM Communications Inc., a Washington corporation
(the "Company"), hereby grants to COMDISCO Inc. or its registered assigns (the
"Registered Holder") the right to purchase from the Company 117,000 shares of
the Company's Common Stock at a price per share of $10.00 (as adjusted from time
to time hereunder, the "Exercise Price". Certain capitalized terms used herein
are defined in Section 4 hereof. The amount and kind of securities purchasable
pursuant to the rights granted hereunder and the purchase price for such
securities are subject to adjustment pursuant to the provisions contained in
this Warrant.

        This Warrant is subject to the following provisions:

        1.      Exercise of Warrant.

                1.1 Exercise Period. The Registered Holder may exercise, in
whole or in part (but not as to a fractional share of Common Stock), the
purchase rights represented by this Warrant at any time and from time to time
after the Date of Issuance to and including the tenth anniversary thereof (the
"Exercise Period").

                                       1
<PAGE>   2

                1.2     Exercise Procedure.

                        (i)     This Warrant will be deemed to have been
exercised when the Company has received all of the following items (the
"Exercise Time"):

                                (a) a completed Exercise Agreement, as described
                in Section 1.3 below and Exhibit 1.3 attached, executed by the
                Person exercising all or part of the purchase rights represented
                by this Warrant (the "Purchaser");

                                (b)     this Warrant;

                                (c) if this Warrant is not registered in the
                name of the Purchaser, an Assignment or Assignments in the form
                set forth in Exhibit 1.2 hereto evidencing the assignment of
                this warrant to the Purchaser, in which case the Registered
                Holder will have complied with the provisions set forth in
                Section 6 hereof; and

                                (d) a check payable to the Company in an amount
                equal to the product of the Exercise Price multiplied by the
                number of shares of Common Stock being purchased upon such
                exercise or by the surrender of warrants ("Net Issuance") as
                determined below.

                        (ii)    If the Registered Holder or the Purchaser elects
the Net Issuance method, the Company will issue Warrant Shares in accordance
with the following formula:

                         X = Y(A-B)

                  Where: X = the number of Warrant Shares to be issued to the
                             Registered Holder or Purchaser

                         Y = the number of Warrant Shares requested to be
                             exercised under this Warrant Agreement

                         A = the fair market value of one (1) share of Common
                             Stock

                         B = the Exercise Price

For purposes of the above calculation, current fair market value of Common Stock
shall mean with respect to each share of Common Stock:

                                (a)     if traded on a securities exchange, the
                fair market value shall be deemed to be the weighted average of
                the closing prices over five (5) consecutive trading days
                commencing one day after the Company has received an executed
                copy of the Exercise Agreement from the Holder, wherein
                weighting

                                       2
<PAGE>   3

                shall be determined by the number of shares traded on each such
                trading day times the closing price for such day; or

                                (b)     if actively traded over-the-counter, the
                fair market value shall be deemed to be the average of the
                closing bid and asked prices quoted on the NASDAQ system (or
                similar system) over the twenty-one (21) day period ending three
                days before the day the current fair market value of the
                securities is being determined; or

                                (c)     if at any time the Common Stock is not
                listed on any securities exchange or quoted in the NASDAQ System
                or the over-the-counter market, the current fair market value of
                Common Stock shall be the highest price per share which the
                Company could obtain from a willing buyer (riot a current
                employee or director) for shares of Common Stock sold by the
                Company, from authorized but unissued shares, as determined in
                good faith by its Board of Directors.

                        (iii)   Certificates for Warrant Shares purchased upon
exercise of this Warrant will be delivered by the Company to the Purchaser
within five days after the date of the Exercise Time. Unless this Warrant has
expired or all of the purchase rights represented hereby have been exercised,
the Company will prepare a new Warrant, substantially identical hereto,
representing the rights formerly represented by this Warrant which have not
expired or been exercised and will, within such five-day period, deliver such
new Warrant to the Person designated for delivery in the Exercise Agreement.

                        (iv)    The Warrant Shares issuable upon the exercise of
this Warrant will be deemed to have been issued to the Purchaser at the Exercise
Time, and the Purchaser will be deemed for all purposes to have become the
record holder of such Warrant Shares at the Exercise Time.

                        (v)     The issuance of certificates for Warrant Shares
upon exercise of this Warrant will be made without charge to the Registered
Holder or the Purchaser of any issuance or transfer tax in respect thereof or
other cost incurred by the Company in connection with such exercise and the
related issuance of Warrant Shares. Each Warrant Share issuable upon exercise of
this Warrant will, upon payment of the Exercise Price, be fully paid and
nonassessable and free from all liens and charges with respect to the issuance
thereof.

                        (vi)    The Company will not close its books against the
transfer of this Warrant or of any Warrant Share issued or issuable upon the
exercise of this Warrant in any manner which interferes with the timely exercise
of this Warrant. The Company will from time to time take all such action as may
be necessary to assure that the par value per share of the unissued Warrant
Shares acquirable upon exercise of this Warrant is at all times equal to or less
than the Exercise Price then in effect.




                                       3
<PAGE>   4



                        (vii)   The Company shall assist and cooperate with any
Registered Holder or any Purchaser required to make any Governmental filings or
obtain any governmental approvals prior to or in connection with any exercise of
this Warrant (including, without limitation, making any filings required to be
made by the Company), except that the Company shall not be required to register
the Warrant Shares under the Securities Act or under any other securities laws
in connection with the exercise of this Warrant.

                        (viii)  The Company shall at all times reserve and keep
available out of its authorized but unissued shares of Common Stock solely for
the purpose of issuance upon the exercise of the Warrants, such number of shares
of Common Stock issuable upon the exercise of all outstanding Warrants. All
shares of Common Stock which are so issuable shall, when issued, be duly and
validly issued, fully paid and nonassessable without charge to Registered Holder
or Purchaser for the payment of taxes, and free from all other liens and other
charges. The Company shall take all such actions as may be necessary to assure
that all such shares of Common Stock may be so issued without violation of any
applicable law or Governmental regulation or any requirements of any domestic
securities exchange upon which shares of Common Stock may be listed (except for
official notice of issuance which shall be immediately delivered by the Company
upon each such issuance).

                        (ix)    Upon any exercise of this warrant, the Company
may require customary representations from the Registered Holder and the
Purchaser to assure that the issuance of the Common stock hereunder shall not
require registration or qualification under the Securities Act or any state
securities laws.

                1.3     Exercise Agreement. Upon any exercise of this Warrant,
the Exercise Agreement will be substantially in the form set forth in Exhibit
1.3 hereto, except that if the Warrant Shares are not to be issued in the name
of the Person in whose name this Warrant is registered, the Exercise Agreement
will also state the name of the Person to whom the certificates for the Warrant
Shares are to be issued, and if the number of Warrant Shares to be issued does
not include all the shares of Common stock purchasable hereunder, it will also
state the name of the Person to whom a new Warrant for the unexercised portion
of the rights hereunder is to be delivered. Such Exercise Agreement will be
dated the actual date of execution thereof. Notwithstanding the foregoing,
Warrant Shares will not be issued in the name of a Person other than the
Registered Holder, nor will replacement Warrants or the balance of a Warrant be
issued in the name of a Person other than the Registered Holder, except pursuant
to the procedure set forth in Section 6 below.

                1.4     Fractional Shares. If a fractional share of Common Stock
would, but for the provisions of Section 1.1, be issuable upon exercise of the
rights represented by this Warrant, the Company will, within five days after the
date of the Exercise Time, deliver to the Purchaser a check payable to the
Purchaser in lieu of such fractional share in an amount equal to the difference
between market price of such fractional share as of the date of the Exercise
Time and the Exercise Price of such fractional share.



                                       4
<PAGE>   5


        2.      Adjustment of Exercise Price and Number of Shares. In order to
prevent dilution of the rights granted under his Warrant, the Exercise Price
shall be subject to adjustment from time to time as provided in his Section 2,
and the number of Warrant Shares obtainable upon exercise of this Warrant shall
be subject to adjustment from time to time as provided in this Section 2.

                2.1     Subdivision or Combination of Common Stock. If the
Company at any time subdivides (by any stock split, stock dividend,
recapitalization or otherwise) the Common Stock into a greater number of shares,
the Exercise Price in effect immediately prior to such subdivision will be
proportionately reduced and the number of Warrant Shares obtainable upon
exercise of this warrant will be proportionately increased so as to prevent the
reduction or enlargement of rights under this Warrant. If the Company at any
time combines (by reverse stock split or otherwise) the Common Stock into a
smaller number of shares, the Exercise Price in effect immediately prior to such
combination will be proportionately increased and the number of Warrant Shares
obtainable upon exercise of this Warrant will be proportionately decreased so as
to prevent the reduction or enlargement of rights under this Warrant.

                2.2     Reorganization, Reclassification, Consolidation Merger
or Sale. Any recapitalization, reorganization, reclassification, consolidation,
merger, sale of all or substantially all of the Company's assets to another
Person or other transaction which is effected in such a way that holders of
Common Stock are entitled to receive (either directly or upon subsequent
liquidation) stock, securities or assets with respect to or in exchange for
Common Stock by reason of the Company's participation therein is referred to
herein as an "Organic Change." Prior to the consummation of any organic Change,
the Company will make appropriate provision (in form and substance satisfactory
to the holders of a majority of the Warrant Shares) to insure that each of the
Registered Holders of the Warrants will thereafter have the right to acquire and
receive in lieu of or addition to (as the case may be) the Warrant shares
immediately theretofore acquirable and receivable upon the exercise of such
holder's Warrant, such shares of stock, securities or assets as may be issued or
payable with respect to or in exchange for the number of Warrant Shares
immediately theretofore acquirable and receivable upon exercise of such holder's
Warrant had such Organic Change not taken place. In any such case, the Company
will make appropriate provision (in form and substance satisfactory to the
holders of a majority of the warrant Shares) with respect to such holders,
rights and interests to insure that the provisions of this Section 2 hereof will
thereafter be applicable to the Warrants. The Company will not effect any such
Organic Change, unless prior to the consummation thereof, the successor entity
(if other than the Company) resulting from such Organic Chancre (including,
without limitation, a purchaser of all or substantially all the Company's
assets) assumes by written instrument, the obligation to deliver to each such
holder such shares of stock, securities or assets as, in accordance with the
foregoing provisions, such holder may be entitled to acquire upon exercise of
Warrants.

                2.3     Certain Events. If any event occurs of the type
contemplated by the provisions of this Section 2 but not expressly provided for
by such provisions (including, without limitation, the granting of stock-
appreciation rights, phantom stock rights or other rights with







                                       5
<PAGE>   6

equity features), then the Company's Board of Directors will make an appropriate
adjustment in the Exercise Price and the number of Warrant Shares obtainable
upon exercise of this Warrant so as to protect the rights of the holders of the
Warrants; provided that no such adjustment will increase the Exercise Price or
decrease the number of Warrant Shares except as described in subsection 2.1
(reverse stock split).

                2.4     Notices.

                        (i)     Promptly following the occurrence of any event
requiring any adjustment of the Exercise Price pursuant to this Section 2, the
Company will give written notice thereof to the Registered Holder, setting forth
in reasonable detail and certifying the calculation of such adjustment.

                        (ii)    The Company will give written notice to the
Registered Holder at least 20 days prior to the date on which the Company closes
its books or takes a record (A) with respect to any dividend or distribution
upon the Common Stock, (B) with respect to any pro rata subscription offer to
holders of Common Stock or (C) for determining rights to vote with respect to
any Organic Change, dissolution or liquidation.

                        (iii)   The Company will also give written notice to the
Registered Holder at least 20 days prior to the date on which any Organic
Change, dissolution or liquidation takes place.

        3.      Liquidating Dividends. If the Company declares or pays a
dividend upon the Common Stock payable otherwise than in cash out of earnings or
earned surplus (determined in accordance with generally accepted accounting
principles, consistently applied) except for a stock dividend payable in shares
of Common Stock (a ("Liquidating Dividend"), then the Company will pay to the
Registered Holder of this Warrant at the time of payment thereof the Liquidating
Dividend which would have been paid to such Registered Holder on the Common
Stock had this Warrant been fully exercised immediately prior to the date on
which a record is taken for such Liquidating Dividend, or, if no record is
taken, the date as of which the record holders of Common Stock entitled to such
dividends are to be determined.

        4.      Definitions. The following terms have meanings set forth below:

                "Common" means the Company's Common Stock, par value $0.0001 per
                share.

                "Common Stock" means the Company's Common Stock, except for 
purposes of the shares obtainable upon exercise of this Warrant, any capital
stock of the Company hereafter authorized which is not limited to a fixed sum or
percentage of par or stated value in respect to the rights of the holders
thereof to participate in dividends or in the distribution of assets upon any
liquidation, dissolution or winding up of the Company.

                                       6
<PAGE>   7


                "Registered Holder" means the holder of this warrant as
reflected in the records of the Company maintained pursuant to Section II
below.

                "Warrant" is defined in Section 7 below.

                "Warrant Shares" means shares of Common Stock issued or issuable
directly or indirectly upon exercise of the Warrant; provided, however, that if
the securities issuable upon exercise of the Warrant are issued by an entity
other than the Company or there is a chancre in the class of securities so
issuable, then the term "Warrant Shares" shall mean shares of the security
issuable upon exercise of the Warrant if such security is issuable in shares, or
shall mean the equivalent units in which such security is issuable if such
security is not issuable in shares.

        5.      No Voting Rights: Limitations of Liability. This Warrant will
not entitle the holder hereof to any voting rights or other rights as a
stockholder of the Company. No provision hereof, in the absence of affirmative
action by the Registered Holder to purchase Common Stock, and no enumeration
herein of the rights or privileges of the Registered Holder shall give rise to
any liability of such holder for the Exercise Price of Common Stock acquirable
by exercise hereof or as a stockholder of the Company.

        6.      Warrant Transferable. Subject to the transfer conditions
referred to in the legend endorsed hereon, this warrant and all rights hereunder
are transferable upon the prior written consent of the Company (which consent
shall not be unreasonably withheld), in whole or in part, without charge to the
Registered Holder, upon surrender of this Warrant with a properly executed
Assignment (in the form of Exhibit 1.2 hereto) at the principal office of the
Company; provided, however, that the Registered Holder may transfer this Warrant
and all rights hereunder to an Affiliate without the prior written consent of
the Company. Notwithstanding the foregoing, the restrictions imposed upon the
transferability of this Warrant or Warrant Shares acquired pursuant to the
exercise of this Warrant do not apply to transfers from the beneficial owner of
any of the aforementioned securities to its nominee or from such nominee to its
beneficial owner, and shall terminate as to any particular Warrant Shares when
(1) such security shall have been effectively registered under the 1933 Act and
sold by the Registered Holder or Purchaser thereof in accordance with such
registration or (2) such Warrant Shares shall have been sold without
registration in compliance with Rule 144 under the Securities Act, or (3) a
letter shall have been issued to the Registered Holder or Purchaser at its
request by the staff of the Securities and Exchange Commission or a ruling shall
have been issued to the Holder at its request by such Commission stating that no
action shall be recommended by such staff or taken by such Commission as the
case may be, if such security is transferred without registration under the
Securities Act in accordance with the conditions set forth in such letter or
ruling and such letter or ruling specifies that no subsequent restrictions on
transfer are required. Whenever the restrictions imposed hereunder shall
terminate, as hereinabove provided, the Registered Holder or Purchaser of
Warrant Shares then outstanding as to which such restrictions have terminated
shall be entitled to receive from the Company, without expense to such
Registered Holder or Purchaser, one or more new certificates for the Warrant or
for such Warrant Shares not bearing any restrictive legend.


                                       7
<PAGE>   8



        7.      Warrant Exchangeable for Different Denominations. This Warrant
is exchangeable, upon the surrender hereof by the Registered Holder at the
principal office of the Company, for new Warrants of like tenor representing in
the aggregate the purchase rights hereunder, and each of such new warrants will
represent such portion of such rights as is designated by the Registered Holder
at the time of such surrender. The date the Company initially issues this
Warrant will be deemed to be the "Date of Issuance" hereof regardless of the
number of times new certificates representing the unexpired and unexercised
rights formerly represented by this warrant shall be issued. All Warrants
representing portions of the rights hereunder are referred to herein as the
"Warrants."

        8.      Replacement. Upon receipt of evidence reasonably satisfactory to
the Company (an affidavit of the Registered Holder will be satisfactory) of the
ownership and the loss, theft, destruction or mutilation of any certificate
evidencing this Warrant, and in the case of any such loss, theft or destruction,
upon receipt of indemnity reasonably satisfactory to the Company (provided that
if the holder is a financial institution or other institutional investor its own
agreement will be satisfactory), or, in the case of any such mutilation upon
surrender of such certificate, the Company will at its expense (execute and
deliver in lieu of such certificate a new certificate of like kind representing
the same rights represented by such lost, stolen, destroyed or mutilated
certificate and dated the date of such lost, stolen, destroyed or mutilated
certificate. 

        9.      Accredited Investor. Registered Holder represents and warrants
it (i) has such knowledge and experience in financial and business matters as to
be capable of evaluating the merits and risks of its investment, and has the
ability to bear the economic risks of its investment; and (ii) is an "accredited
investor" within the meaning of the Securities and Exchange Rule 501 of
Regulation D, as presently in effect.

        10.     Representations, Warranties and Covenants of the Company.

                (a)     Due Authority. The execution and delivery by the Company
of this Warrant and the performance of all obligations of the Company hereunder,
including the issuance to Registered Holder or Purchaser of the right to acquire
Warrant Shares, have been duly authorized by all necessary corporate action on
the part of the Company, and this Warrant is not inconsistent with the Company's
Amended and Restated Articles of Incorporation, does not contravene any law or
governmental rule, regulation or order applicable to it, does not and will not
contravene any provision of, or constitute a default under, any indenture,
mortgage, contract or other instrument to which it is a party or by which it is
bound, and this Warrant constitutes a legal, valid and binding agreement of the
Company, enforceable in accordance with its respective terms.

                (b)     Consents and Approvals. No consent or approval of,
giving of notice to, registration with, or taking of any other action in respect
of any state, Federal or other governmental authority or agency is required with
respect to the execution, delivery and performance by the Company of its
obligations under this Warrant, except for the filing of notices




                                       8
<PAGE>   9



pursuant to Regulation D under the 1933 Act and any filing required by
applicable state securities law, which will be effective by the time required
thereby.

                (c)     Issued Securities. All issued and outstanding shares of
Common Stock, or any other securities of the Company have been duly authorized
and validly issued and are fully paid and nonassessable. All outstanding shares
of Common Stock, and any other securities were issued in full compliance with
all Federal and state securities laws.

                (d)     Exempt Transaction. Subject to the accuracy of the
Registered Holder's representations in Section 9 hereof, the issuance of Warrant
Shares upon exercise of this Warrant will constitute a transaction exempt
from (i) the registration requirements of Section 5 of the Securities Act, in
reliance upon Section 4(2) thereof, and (ii) the qualification requirements of
the applicable state securities law.

                (e)     Compliance with Rule 144. At the written request of
Registered Holder or Purchaser, who proposes to sell Warrant Shares issuable
upon the exercise of this Warrant in compliance with Rule 144 promulgated by the
Securities and Exchange Commission, the Company shall use all commercially
reasonable efforts to furnish to the Registered Holder or Purchaser, in due
course after receipt of such request, a written statement confirming the
Company's compliance with the filing requirements of the Securities and Exchange
Commission as set forth in such Rule, as such Rule may be amended from time to
time.

        11.     Notices. Except as otherwise expressly provided herein, all
notices referred to in this Warrant will be in writing and will be delivered
personally, sent by reputable express courier service (charges prepaid) or sent
by registered or certified mail, return receipt requested, postage prepaid and
will be deemed to have been given when so delivered (or when received, if
delivered by any other method) if sent (i) to the Company, at its principal
executive offices and (ii) to a Registered Holder of this Warrant, 6111 North
River Road, Rosemont, Illinois 60018, attention: Rick Finocchi, with a copy to
attention: General Counsel (facsimile (847) 518-5440 and (847) 518-5088) (unless
otherwise indicated in writing by any such holder).

        12.     Amendment and Waiver. Except as otherwise provided herein, the
provisions of the Warrants may be amended and the Company may take any action
herein prohibited, or omit to perform any act herein required to be performed by
it, if, but only if, the Company has obtained the written consent of the holders
of Warrants representing a majority of the Warrant Shares issuable upon exercise
of all outstanding Warrants, issued hereunder. Nothing herein shall otherwise
prevent the Company and COMDISCO, Inc. (as long as it remains the Registered
Holder of a majority of the Warrant Shares) from entering into an amendment of
this Stock Purchase Warrant provided such amendment is by written instrument
signed by the Company and such Registered Holder.

        13.     Warrant Register. The Company shall maintain at its principal
executive offices books for the registration and the registration of transfer
of warrants. The Company may deem and treat the Registered Holder as the
absolute owner hereof (notwithstanding any notation of



                                       9
<PAGE>   10



ownership or other writing thereon made by anyone) for all purposes and shall
not be affected by any notice to the contrary, other than a transfer in
accordance with the provisions of Section 6 hereof.

        14.     Registration Rights. If (i) on or before June 30, 1998, or (ii)
until such time as all of the Warrant Shares can be sold within three months
without compliance with the registration requirements of the Securities Act
pursuant to Rule 144 promulgated thereunder (whichever is earlier), the Company
proposes to register any of its shares of Common Stock under the Securities Act
of 1933, as amended (the "Securities Act") in connection with an underwritten
public offering of such Common Stock for the account of the Company solely for
cash on a form that would also permit registration of the Warrant Shares, it
will promptly give written notice to Holder of its intention to do so and, upon
the written request of Holder given within twenty (20) days after receipt of any
such notice (which request shall specify the number of Shares desired to be
included in such underwritten public offering by Holder), the Company will use
its reasonable best efforts to cause all Warrant Shares requested by Holder to
be included in such underwritten public offering; provided, however, that the
Company shall not be required to cause any Shares to be so registered or
included or to give notice of registration (i) if in the underwriters' opinion
the inclusion will jeopardize the success of the offering of shares of Common
Stock by the Company or (ii) in the case of a registration on any form which
does not include substantially the same information as would be required to be
included in the registration statement covering the sale of Shares for cash. If
some but not all shares of Common Stock with respect to which the Company shall
have received requests for registration pursuant to piggyback registration
rights granted hereunder or pursuant to any other agreement shall be excluded
from such registration, the Company shall make appropriate allocation of shares
to be registered among all holders of Common Stock having a contractual right to
register their shares and at the time desiring to register their shares pro rata
in the proportion that the number of shares of Common Stock held by all such
holders then desiring to have their shares registered for sale. With respect to
the Warrant Shares so included, Holder shall bear the cost of any underwriting
discount or selling expenses for the sale of such Shares and the cost of the
attorneys' fees for Holder's own attorney, if any, and the Company shall bear
all other costs and expenses of the registration, including attorneys and
accountants fees, printing costs, SEC and blue sky filing fees and transfer
agent fees and expenses. The Company shall not be required under this Section 14
to include any of the Warrant Shares in an underwriting of shares unless Holder
(i) accepts the terms of the underwriting as agreed upon between the Company and
the underwriters selected by it, assuming normal and customary underwriting
terms and (ii) furnishes to the Company such information regarding itself as
shall be reasonably required to effect the registration of the Warrant Shares.
The rights granted pursuant to this Section 14 may not be assigned by Holder
without the Company's prior written consent which shall not be unreasonably
withheld. In the event Holder elects to participate in such registration, Holder
hereby agrees that it shall not, to the extent required by the Company and the
underwriter of the offering giving rise to piggyback rights hereunder sell or
otherwise transfer or dispose of (other than to donees who agree to be similarly
bound) any shares of Common Stock during the one-hundred-twenty day period
following the effective date of a registration statement filed by the Company
under the Securities Act with respect to such offering provided that the
Company's insider executive officers and directors have



                                       10
<PAGE>   11


entered into similar lock up agreements with respect to their shares and stock
options, where applicable, for a like period with the underwriter. The Company
retains the right in its sole discretion to abandon or withdraw any registration
statement at any time.

        15.     Descriptive Headings: Governing Law. The descriptive headings of
the several Sections and paragraphs of this warrant are inserted for convenience
only and do not constitute a part of this Warrant. The enforcement,
construction, validity and interpretation of this Warrant will be governed by
the internal law, and not the conflicts law, of Washington.

        IN WITNESS WHEREOF the Company has caused this Warrant to be signed and
attested by its duly authorized officers under its corporate seal and to be
dated the Date of Issuance hereof.

                                           MIDCOM Communications Inc..

                                       By:    /s/ ROBERT J. CHAMBERLAIN
                                          -------------------------------
                                      Its:    CFO
                                          -------------------------------
[Corporate Seal]

Attest:



   /s/ PAUL P. SENIO
-------------------------------
Title: SECRETARY
      -------------------------------



                                       11
<PAGE>   12



                                                                     EXHIBIT 1.3

                               EXERCISE AGREEMENT

To:                                                        Dated:

        The undersigned, pursuant to the provisions set forth in the attached
Warrant (Certificate No. W-5), hereby agrees to subscribe for the purchase of
shares of the Common Stock covered by such Warrant and makes payment herewith in
full therefor at the price per share provided by such Warrant.

                                    Signature
                                              -------------------------------
                                     Address
                                              -------------------------------


                                       12
<PAGE>   13

                                                                     EXHIBIT 1.2

                                   ASSIGNMENT

        FOR VALUE RECEIVED,                               hereby sells, assigns
                           ------------------------------
and transfers all of the rights of the undersigned under the attached Warrant
(Certificate No. W-5) with respect to the number of shares of the Common Stock
covered thereby set forth below, unto:

Names of Assignee            Address                     No. of Shares
-----------------            -------                     -------------

                                    Signature
                                              -------------------------------
                                     Witness
                                              -------------------------------


                                       13