<PAGE>

                                                                    EXHIBIT 2.14

BARBADOS

      THIS DEED OF GUARANTEE AND SUBORDINATION is made as of the 30th day of
June, 2005.

BETWEEN: MITEL NETWORKS INTERNATIONAL LIMITED, a company formed under the laws
         of Barbados with registered office at The Corporate Secretary Limited,
         Whitepark House, Whitepark Road, St. Michael (hereinafter referred to
         as the "Company")

AND:     HIGHBRIDGE INTERNATIONAL LLC, a limited liability company formed under
         the laws of the Cayman Islands having an office at c/o Highbridge
         Capital Management, LLC, 9 West 57th Street, 27th Floor, New York, New
         York, U.S.A. 10019, as collateral agent (in such capacity, the
         "Collateral Agent") for itself as a holder and the other holders
         existing from time to time (each a "Secured Party" and collectively,
         the "Secured Parties"), of senior secured convertible notes initially
         issued as of April 27, 2005, (as amended, restated or supplemented from
         time to time the "Notes"), issued by Mitel Networks Corporation, a
         corporation incorporated under the laws of Canada (the "Issuer")
         pursuant to a Securities Purchase Agreement dated April 27, 2005 (the
         "Securities Purchase Agreement") by and among the Issuer and the buyers
         party thereto

AND:     EACH OF THE INTERCOMPANY CREDITORS (jointly and severally, the
         "Intercompany Creditors") identified in Schedule I hereto.

RECITALS:

A.    Pursuant to the Notes issued by the Issuer pursuant to the Securities
      Purchase Agreement, the Issuer is indebted to the Secured Parties as
      holders from time to time of the Notes.

B.    The Company is a direct wholly-owned subsidiary of the Issuer; and the
      Company will benefit from the arrangements under the issuance of the Notes
      and the receipt of proceeds therefrom by the Issuer.

C.    The Company has agreed to guarantee the obligations of the Issuer and as
      additional security therefor.

D.    The parties hereto have agreed to enter into this Deed of Guarantee and
      Subordination for the purpose of effecting the subordination of the rights
      in respect of certain Intercompany Debts (as defined herein), and for the
      purposes of regulating the claims of the Collateral Agent and the
      Intercompany Creditors against the Company.

<PAGE>

DEED OF GUARANTEE AND SUBORDINATION

IT IS HEREBY AGREED AS FOLLOWS:

1.    DEFINITIONS AND INTERPRETATION

1.1   In this Deed of Guarantee and Subordination unless the context otherwise
      requires the following expressions shall bear the following respective
      meanings:

(a)   "APPLICABLE LAW"        means the law of any one or more jurisdictions
                              which is applicable to the interpretation of the
                              rights and interests created herein, or to the
                              exercise of any power or discretion by the
                              Company, the Collateral Agent or an Intercompany
                              Creditor hereunder, whether by reason of the
                              domicile of the Company, the domicile of the
                              Collateral Agent, the domicile of the Intercompany
                              Creditor, the situs of the whole or any part of
                              the Collateral, or other connecting factor (which
                              is admissible under general principles of law,
                              including relevant principles of conflicts of
                              laws) and includes the Governing Law. Each of the
                              parties hereto shall determine the Applicable Law
                              by reference to the Governing Law, except where
                              that party has actual notice of the applicability
                              hereto of another system or, and each of the
                              parties hereto shall obey the court orders of a
                              court validly claiming jurisdiction in respect
                              hereof;

(c)   "COMPANY"               means any entity with corporate capacity (of
                              whatsoever kind) incorporated or otherwise brought
                              into existence in any part of the world and
                              includes companies, limited liability companies
                              and societies with restricted liability which have
                              liability hereunder;

(d)   "COUNTRY OF DOMICILE"   means any one of the country of residence,
                              nationality or domicile (as appropriate);

(e)   "DEED"                  means any instrument in writing whether in one or
                              more counterparts, in the form appropriate under
                              Applicable Law, and includes deeds, documents
                              under seal, contracts, declarations in writing,
                              memoranda, written resolutions of the Trustee and
                              other instruments in writing;

(f)   "EVENT OF DEFAULT"      means an event which constitutes an Event of
                              Default as described in the Notes, committed by
                              the Company;

(g)   "INSOLVENCY EVENT"      means:

                              (i)   under any Applicable Law, a court making a
                                    final winding up order or an order for the
                                    dissolution or liquidation of (or similar
                                    procedure in respect of) the Company, or

                              (ii)  under any Applicable Law, a liquidator or
                                    administrator or similar official is
                                    appointed to the Company;

                                                                               2
<PAGE>

DEED OF GUARANTEE AND SUBORDINATION

(i)   "INTERCOMPANY DEBTS"    means the book debts, accounts and other amounts
                              receivable, claims, demands, moneys and choses in
                              action which now are due or owing by the Company
                              to or owned, by the Intercompany Creditors and all
                              claims of whatsoever nature or kind which the
                              Intercompany Creditors have or may have against
                              the Company;

(j)   "ISSUER INDEBTEDNESS"   means all claims, indebtedness, liabilities and
                              obligations of the Issuer to the Secured Parties
                              under and in connection with the Securities
                              Purchase Agreement and the Notes;

(k)   "ISSUER DISCHARGE DATE" means the date on which:

                              (i)  all of the Issuer Indebtedness has been
                                   fully discharged, or

                              (ii) a Qualified IPO (as defined in the Notes) is
                                   consummated;

(l)   "PERSON"                means any individual or any body of persons
                              corporate or unincorporate, and includes
                              individuals, companies, bodies corporate, limited
                              liability companies, societies with restricted
                              liability, partnerships (whether limited or
                              general), firms, syndicates, joint ventures,
                              trusts, unincorporated associations, governmental
                              authorities and agencies, and any legal entity or
                              any other association of persons;

(m)   "PROPER LAW"            means the law, as determined in accordance with
                              this Deed of Guarantee and Subordination, to the
                              exclusive jurisdiction of which the rights of all
                              parties and the construction and effect of each
                              and every provision of this Deed of Guarantee and
                              Subordination shall be subject and by which such
                              rights, construction and effect shall be construed
                              and regulated.

1.2   Capitalised terms not defined in this Deed of Guarantee and Subordination,
      unless otherwise indicated, shall have the meanings assigned to such terms
      in the Notes.

1.3   Terms defined elsewhere in this Deed of Guarantee and Subordination,
      unless otherwise indicated, shall have such meaning in every section
      herein.

1.4   Where the context permits, any reference to "Collateral" in this Deed of
      Guarantee and Subordination, shall be deemed to be a reference to
      "Collateral or any part thereof."

1.5   Unless the context clearly requires otherwise, the words "hereof "herein"
      and "hereunder" and words of similar import, when used in this Deed of
      Guarantee and Subordination, shall refer to this Deed of Guarantee and
      Subordination as a whole and not to any particular section; wherever the
      word "include" "includes" or "including" is used in any provision of this
      Deed of Guarantee and Subordination, it shall be deemed to be followed by
      the words "without limitation" unless clearly indicated otherwise.

                                                                               3
<PAGE>

DEED OF GUARANTEE AND SUBORDINATION

1.6   The singular includes the plural and the plural includes the singular; and
      the masculine gender includes the feminine and neuter genders.

1.7   The division of this Deed of Guarantee and Subordination into sections,
      articles and paragraphs, the provision of a table of contents and the
      insertion of headings are for convenience of reference only and shall not
      affect the construction or interpretation hereof.

2.    GUARANTEE OF OBLIGATIONS OF ISSUER

2.1   The Company hereby unconditionally GUARANTEES to the Collateral Agent and
      each of the Secured Parties payment of all present and future
      indebtedness, liabilities and obligations, whether direct or indirect,
      absolute or contingent, now or hereafter owing by the Issuer to the
      Secured Parties (collectively, the "Obligations"). The Company shall pay
      to the Collateral Agent for itself and the Secured Parties, on demand by
      the Collateral Agent, all amounts owing by the Company to the Collateral
      Agent for itself and the Secured Parties hereunder and the Company shall
      pay to the Collateral Agent for itself and the Secured Parties interest
      thereon after demand at the highest rate of interest payable on the
      Obligations or any part or parts thereof.

2.2   No change in the name, objects, capital or constitution of the Issuer or
      any other matter relating to the Issuer, shall in any way affect the
      liability of the Company, either with respect to transactions occurring
      before or after any such change.

2.3   The Collateral Agent, without consent of the Company and without
      exonerating in whole or in part the Company may grant time, renewals,
      extensions, indulgences, releases and discharges to the Issuer and all
      other persons (including the Company, and any other guarantor), may take
      securities from and give the same and any or all existing securities up to
      the Issuer and all other persons (including the Company, and any other
      guarantor), may abstain from taking securities from the Issuer and all
      other persons (including the Company, and any other guarantor), or from
      perfecting securities of the Issuer and all other persons (including the
      Company, and any other guarantor), may accept compositions from the Issuer
      and all other persons (including the Company, and any other guarantor),
      and may otherwise change the terms of any of the debts and liabilities
      hereby guaranteed and otherwise deal with the Issuer and all other persons
      (including the Company, and any other guarantor), as the Collateral Agent
      may see fit, and that all dividends, compositions, and moneys received by
      the Collateral Agent from the Issuer or from any other persons or estates
      capable of being applied by the Collateral Agent in reduction of the
      Obligations hereby guaranteed, shall be regarded for all purposes as
      payments in gross, and the Collateral Agent shall be entitled to prove
      against the estate of the Issuer upon any insolvency or winding-up in
      respect of the whole of said debts and liabilities, and the Company shall
      have no right to be subrogated to the Collateral Agent in respect of any
      such proof or otherwise until the Collateral Agent shall have received
      from such estate or from the Company, payment in full of its claim with
      interest.

                                                                               4
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DEED OF GUARANTEE AND SUBORDINATION

2.4   This shall be a continuing guarantee, and shall cover and secure any
      ultimate balance owing to the Secured Parties, including all costs,
      charges and expenses which any Secured Party or the Collateral Agent may
      incur in enforcing or obtaining payment of the sums of money due to the
      Secured Parties from the Issuer either alone or in conjunction with any
      other corporation, person or persons, or otherwise howsoever, or
      attempting to do so. The Collateral Agent shall not be obliged to seek any
      recourse against the Issuer or other persons or the securities it may hold
      before being entitled to payment from the Company of all and every
      Obligation hereby guaranteed. The Company hereby renounces the benefits of
      discussion and division. The Company renounces to claim against, or set up
      against, the Collateral Agent any right which the Company may have to be
      subrogated in any of the rights, hypothecs, privileges and other security
      held from time to time by the Collateral Agent. Every certificate issued
      under the hand of a duly authorised officer of the Collateral Agent,
      purporting to show the amount at any particular time due and payable to
      the Collateral Agent, and covered by this guarantee, shall be received as
      conclusive evidence (in the absence of manifest error) as against the
      Company that such amount is at such time so due and payable to the
      Collateral Agent and is covered hereby.

2.5   All payments made by the Company under this guarantee shall be made free
      and clear and without deduction for any and all present and future taxes,
      levies and withholdings, including without limitation stamp and
      documentary taxes (collectively, the "Taxes"), but excluding taxes imposed
      on the net income of the Collateral Agent. If the Company is required by
      law to deduct any Taxes from or in respect of any amount paid or payable
      hereunder, including without limitation any additional amount or amounts
      payable pursuant to this paragraph, such amount shall be increased as
      necessary so that the Collateral Agent receives an amount or amounts which
      are, in the aggregate, equal to the sum it would have received had no such
      deduction been made and the Company shall pay same to the relevant taxing
      authority and, upon request by the Collateral Agent, shall give to the
      Collateral Agent acceptable evidence of such payments. The Company
      covenants and agrees to indemnify and save harmless the Collateral Agent
      from and against any and all Taxes paid or payable by the Collateral Agent
      in respect of any amounts paid or payable under this guarantee.

3.    SUBORDINATION AND RANKING OF CLAIMS

3.1   Subject to the terms of this Deed of Guarantee and Subordination any and
      all claims of the Collateral Agent (up to the Issuer Indebtedness), shall
      for all purposes and at all times rank ahead of and in priority to the
      Intercompany Debts.

3.2   Each of the Intercompany Creditors hereby expressly and fully subordinates
      and defers its right to payment in accordance with section 3.1 above, to
      any and all claims of the Collateral Agent (up to the Issuer
      Indebtedness). Thereafter the claims of the Collateral Agent and the
      claims of the Intercompany Creditors shall rank pari passu in all respects
      and there shall be no other deferral or subordination of the claims of the
      Intercompany Creditors.

                                                                               5
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DEED OF GUARANTEE AND SUBORDINATION

4.    TURNOVER

4.1.1 If at any time on or before the Issuer Discharge Date, there has been an
      Event of Default or an Insolvency Event, and an Intercompany Creditor:

      (a)   receives or recovers a payment of any kind in respect or on account
            of the in respect of the Intercompany Debts;

      (b)   receives or recovers proceeds pursuant to any enforcement or similar
            action against the Company; or

      (c)   discharges any of the Intercompany Debts by set-off, combination of
            accounts or otherwise;

      that Intercompany Creditor as the beneficiary of that payment,
      distribution, set-off or combination, will promptly pay all amounts and
      distributions to the Collateral Agent and, pending such payments, the
      Intercompany Creditor shall hold such distribution on trust for the
      Collateral Agent.

                                                                               6
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DEED OF GUARANTEE AND SUBORDINATION

5.    COVENANTS

5.1   Each of the Company and the Intercompany Creditors hereby covenants that
      until the Issuer Discharge Date, it shall not:

      (a)   assign, sell, transfer or dispose of any of the Intercompany Debts
            or permit any other person to purchase or acquire any of the
            Intercompany Debts unless such assignee, transferee or purchaser has
            first agreed to be bound by the terms of this Deed of Guarantee and
            Subordination as a party hereto pursuant to a Deed in form and
            content satisfactory to Collateral Agent; and

      (b)   create and the Company shall not permit to subsist any security
            interest or any guarantee or other assurance against financial loss
            in respect of the Intercompany Debts.

6.    SUBORDINATION ON INSOLVENCY

6.1   Upon the occurrence of an Insolvency Event in relation to the Company, the
      Intercompany Debts will fully and unconditionally be subordinate in right
      of payment to any and all claims of the Collateral Agent.

6.2.1 Upon the occurrence of an Insolvency Event in relation to the Issuer or
      the Company, as the case may be, the Collateral Agent is irrevocably and
      severally authorised by each other relevant party to this Deed on their
      behalf to (a) demand, claim, enforce and prove for, (b) file claims and
      proofs, give receipt and take all proceedings and do all things which the
      Collateral Agent considers reasonably necessary to recover, and (c)
      receive distributions of any kind whatsoever, in respect or on account of,
      the Intercompany Debts.

6.2.2 If, for any reason whatsoever, the Collateral Agent is not entitled to
      take any such action for the recovery of any of Intercompany Debts, each
      other party to this Deed (as the case may be) undertakes to take any
      action and give any notices which the Collateral Agent reasonably requires
      from time to time.

6.3.1 Upon the occurrence of an Insolvency Event in relation to the Issuer or
      the Company, as the case may be, the Collateral Agent is irrevocably and
      severally authorised by each other party to this Deed on their behalf to
      exercise all powers of convening meetings, voting and representation in
      respect of the Intercompany Debts, and each other party to this Deed will
      provide all forms of proxy and of representation requested by the
      Collateral Agent for that purpose.

6.3.2 If, for any reason whatsoever, the Collateral Agent is not entitled to
      take any such action or exercise any such powers, each other party to this
      Deed undertakes to take any action and exercise any powers which the
      Collateral Agent reasonably requires from time to time.

                                                                               7
<PAGE>

DEED OF GUARANTEE AND SUBORDINATION

6.4   Upon the occurrence of an Insolvency Event in relation to the Issuer, or
      the Company as the case may be, the trustee in bankruptcy, liquidator,
      assignee, receiver-manager, receiver, manager, or other person
      distributing their assets or their proceeds (an "Insolvency Office
      Holder") shall be directed by each other party as applicable to this Deed
      of Guarantee and Subordination to pay distributions of any kind directly
      to Collateral Agent until the Issuer Indebtedness has been fully
      discharged.

6.5   If an Intercompany Creditor receives a payment or distribution from an
      Insolvency Office Holder directly, such Intercompany Creditor shall hold
      such payment or distribution in trust for the Collateral Agent pending an
      application thereof in accordance with section 6.4.

6.6   The Collateral Agent may (subject to the provisions of this Deed of
      Guarantee and Subordination):

      (a)   apply any moneys received under this Deed of Guarantee and
            Subordination to any item of account or liability in respect of the
            Issuer Indebtedness in any order or manner which it may determine in
            its sole and absolute discretion; and

      (b)   hold any moneys received under this Deed of Guarantee and
            Subordination in a trust account (bearing interest at a market rate
            usual for accounts of that type) unless and until those moneys are
            sufficient in aggregate in order to bring about the Issuer Discharge
            Date.

7.    PROTECTION OF SUBORDINATION

7.1   The subordination provisions in this Deed of Guarantee and Subordination
      constitute a continuing subordination and benefit to the ultimate
      aggregate balance of the Issuer Indebtedness, and the claims of the
      Collateral Agent for and on behalf of the Secured Parties, regardless of
      any intermediate payment or discharge of the Issuer Indebtedness in whole
      or in part.

7.2   The subordination and priority provisions in this Deed of Guarantee and
      Subordination will not be affected by any act, omission , occurrence or
      circumstance whatsoever which (but for this provision) may operate to
      release, extricate or otherwise exonerate any party to this Deed of
      Guarantee and Subordination from their obligations under this Deed of
      Guarantee and Subordination or otherwise affect those subordination and
      priority provisions, including (without limitation):

      (a)   any time or indulgence granted to or composition with any person;

      (b)   the taking, amendment, replacement, substitution, compromise,
            renewal or release of or refusal to enforce or exercise any rights,
            remedies or securities against or granted by the Issuer or the
            Company as the case may be;

      (c)   any legal or equitable limitation, disability, incapacity,
            impairment or other circumstance relating to any Intercompany
            Creditor or the Company as the case may be or any other person or
            any amendment, supplement, substitution or replacement of the terms
            of this Deed of Guarantee and Subordination or any other document;

      (d)   any fluctuation in or partial repayment or prepayment of the Issuer
            Indebtedness;

                                                                               8
<PAGE>

DEED OF GUARANTEE AND SUBORDINATION

      (e)   the giving or failing to give any notice, or the sequence or order
            of giving any notice to any person; or

      (f)   the time, sequence or order of creating, granting, executing,
            delivering or registering, or any failure in respect thereof, of any
            notice, caveat, financing statement or other document.

7.3   The Company is a party to this Deed of Guarantee and Subordination inter
      alia in order to acknowledge the priorities, rights and obligations set
      out in this Deed of Guarantee and Subordination and undertakes not to take
      or agree to take any action whereby the ranking and or subordination
      provided for in this Deed of Guarantee and Subordination may be impaired.

8.    WARRANTY OF CAPACITY AND FURTHER ASSURANCES

8.1   Each party to this Deed of Guarantee and Subordination represents and
      warrants to the other that it has full authority, power and capacity to
      enter into and carry out its obligations under this Deed of Guarantee and
      Subordination and that all necessary acts and things have been taken or
      done to enable it lawfully to enter into and carry out its obligations
      under this Deed of Guarantee and Subordination and that when executed,
      this Deed of Guarantee and Subordination will create obligations which are
      valid and binding on it and enforceable in accordance with their terms.

8.2   Each of the parties agrees to perform (or procure the performance of) all
      further acts and things, and execute and deliver (or procure the execution
      and delivery of) such further documents, as may be required by law or as
      may be necessary or desirable to implement and/or give effect to this Deed
      of Guarantee and Subordination.

9.    ASSIGNMENT OF RIGHTS BY COLLATERAL AGENT

9.1.1 The Collateral Agent (in this capacity the "Transferor"), may at any time
      assign any of its rights under this Deed of Guarantee and Subordination or
      transfer any of its rights and obligations under this Deed of Guarantee
      and Subordination to any person (a "Transferee").

9.1.2 An assignment or transfer in accordance with section 9.1.1, will only be
      effective if the Transferor and the Transferee execute an Accession Deed
      under which the Transferee agrees to be bound by all of the terms of this
      Deed of Guarantee and Subordination as if an original party thereto. Each
      of the parties to this Deed of Guarantee and Subordination (other than the
      Transferee) irrevocably authorises the Collateral Agent to execute on its
      behalf any Accession Deed that has been duly completed and executed by the
      Transferor and the Transferee. The Collateral Agent will promptly notify
      the other parties to this Deed of Guarantee and Subordination of the
      receipt and execution by it on their behalf of any Accession Deed.

10.   FUNDS HELD BY COLLATERAL AGENT

                                                                               9
<PAGE>

DEED OF GUARANTEE AND SUBORDINATION

10.1.1 After the final and conclusive settlement of all claims of the Collateral
       Agent (up to the Issuer Indebtedness), any funds or amounts received by
       the Collateral Agent, shall be held on trust for and promptly applied as
       follows:

       (a)   prior to the occurrence of an Insolvency Event, to the Intercompany
             Creditor; and

       (b)   following the occurrence of an Insolvency Event to the Company or
             the Insolvency Office Holder (as may be appropriate).

11.    GENERAL

11.1.1 Notices: All notices, requests, demands or other communication by the
       terms hereof required or permitted to be given by either party to the
       other shall, unless otherwise specifically provided for herein, be given
       in writing and be delivered by personal delivery or courier delivery and
       by transmittal by electronic means of communication addressed to such
       other party as follows:

       If to the Collateral Agent:             If to the Company:
       Highbridge International LLC            Mitel Networks International
                                               Limited
       c/o Highbridge Capital Management, LLC  c/o Corporate Secretary Limited
       9 West 57th Street, 27th Floor          Whitepark House
       New York                                Whitepark Road
       New York 10019                          Bridgetown
       U.S.A.                                  Barbados

       If to an Intercompany Creditor:
       - at the address set forth for such Intercompany Creditor in Schedule I.

11.1.2 Any party may from time to time by notice to the other party change the
       address to which notices are to be given. Any communication shall be
       conclusively deemed to have been given on the day of actual delivery
       thereof or on the day of actual transmission thereof if such day is a
       business day and the communication is delivered or transmitted during the
       normal business hours of the recipient and on the business day during
       which normal business hours next occur if given after such hours on any
       day.

11.2   Counterparts: This Deed of Guarantee and Subordination may be executed in
       any number of counterparts, each of which shall be deemed an original,
       but all of which collectively shall constitute one and the same
       instrument representing this Deed of Guarantee and Subordination between
       the parties hereto and it shall not be necessary for the proof of this
       Deed of Guarantee and Subordination that any party produce or account for
       more than one such counterpart.

                                                                              10
<PAGE>

DEED OF GUARANTEE AND SUBORDINATION

11.3   Invalid Provisions: If any provision of this Deed of Guarantee and
       Subordination is held to be illegal or invalid or unenforceable, such
       provision shall be fully severable, and this Deed of Guarantee and
       Subordination shall be construed and enforced as if such illegal, invalid
       or unenforceable provision had never comprised a part of this Deed of
       Guarantee and Subordination, and the remaining provisions of this Deed of
       Guarantee and Subordination shall remain in full force and effect and
       shall not be affected by the illegal, invalid or unenforceable provision
       or by its severance from this Deed of Guarantee and Subordination.

11.4   Governing Law: This Deed of Guarantee and Subordination shall be governed
       by, and construed in accordance with, the laws of Barbados and the Courts
       of Barbados shall have non-exclusive jurisdiction herein.

                                                                              11
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DEED OF GUARANTEE AND SUBORDINATION

      IN WITNESS WHEREOF, the parties have executed this Agreement on the date
first hereinbefore written.

THE COMMON SEAL of                                )
MITEL NETWORKS                                    )
INTERNATIONAL LIMITED                             )
was hereto set and affixed by                     )       Paul Butcher, Director
                                                  )       /s/ Paul Butcher
                                                  )
                                                  )
                                                  )
                                                  )
                                                  )

Witness:    S. Felskie

Name:       Sandra Felskie
Address:    Ottawa, ON, CANADA
Occupation: Manager

SIGNED SEALED AND DELIVERED                       )
and hereby executed and delivered as a Deed by    )
HIGHBRIDGE INTERNATIONAL LLC                      )
By: Highbridge Capital Management, LLC            )
                                                  )
                                                  )
By: /s/ Adam J. Chill                             )
    ----------------------------
Adam J. Chill, Managing Director

Witness:

Name:
Address:
Occupation:

                                                                              12
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DEED OF GUARANTEE AND SUBORDINATION

                                   SCHEDULE I

      NAME AND ADDRESS OF INTERCOMPANY CREDITOR
      MITEL NETWORKS OVERSEAS LIMITED
      The Corporate Secretary Limited
      Whitepark House
      Whitepark Road
      St. Michael

 THE COMMON SEAL of                               )
 MITEL NETWORKS                                   )
 OVERSEAS LIMITED                                 )
 was hereto set and affixed by                    )       Paul Butcher, Director
                                                  )       /s/ Paul Butcher
                                                  )
                                                  )
                                                  )
                                                  )
                                                  )

 Witness:    S. Felskie

 Name:       Sandra Felskie
 Address:    Ottawa, ON, CANADA
 Occupation: Manager


                                                                              13
<PAGE>

DEED OF GUARANTEE AND SUBORDINATION

      IN WITNESS WHEREOF, the parties have executed this Agreement on the date
first hereinbefore written.

THE COMMON SEAL of                                )
MITEL NETWORKS                                    )
INTERNATIONAL LIMITED                             )
was hereto set and affixed by                     )      Countersigned
                                                  )
the Secretary thereof in the presence of:         )
                                                  )        Secretary
                                                  )
                                                  )   Directors
                                                  )

Witness:

Name:
Address:
Occupation:

SIGNED SEALED AND DELIVERED                       )
and hereby executed and delivered as a Deed by    )
HIGHBRIDGE INTERNATIONAL LLC                      )
By: Highbridge Capital Management, LLC            )
                                                  )
                                                  )
By: /s/ Adam J. Chill                             )
    ----------------------------
Adam J. Chill, Managing Director

Witness:    /s/ Scott M. Wallace

Name:       Scott M. Wallace
Address:    c/o Highbridge Capital Management, LLC
            9 West 57th Street, 27th Floor
            New York, NY 10019
Occupation: Vice President

                                                                              12
<PAGE>

DEED OF GUARANTEE AND SUBORDINATION

                                   SCHEDULE I

      NAME AND ADDRESS OF INTERCOMPANY CREDITOR
      MITEL NETWORKS OVERSEAS LIMITED
      The Corporate Secretary Limited
      Whitepark House
      Whitepark Road
      St. Michael

THE COMMON SEAL of                                )
MITEL NETWORKS                                    )
OVERSEAS LIMITED                                  )
was hereto set and affixed by                     )       Paul Butcher, Director
                                                  )       /s/ Paul Butcher
                                                  )
                                                  )
                                                  )
                                                  )
                                                  )

 Witness:    S. Felskie

 Name:       Sandra Felskie
 Address:    Ottawa, ON, CANADA
 Occupation: Manager


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