EXHIBIT
F

    


    GUARANTY
AGREEMENT

    


    THIS GUARANTY AGREEMENT
(“Guaranty”) is dated as
of ____________ ___, 2009, and is made effective as of ___________ __, 2009 (the
“Effective Date”) by the
undersigned (each hereinafter referred to as a “Guarantor” and collectively,
the “Guarantors”), in
favor of the purchasers (each a “Investor” and collectively the
“Investors”) of the 8%
exchangeable convertible notes due March 31, 2011 (the “Notes”) and the Warrants
issued pursuant to a Securities Purchase Agreement among MOBIZONE HOLDINGS LIMITED, a
Hong Kong corporation (“MobiZone Hong Kong”), the
Guarantors, certain other Persons or are parties thereto and such Investors,
dated as of June 1, 2009  (the “Securities Purchase
Agreement”) and the Exhibits to the Securities Purchase Agreement, all
dated as of June 1, 2009 (with the Securities Purchase Agreement, collectively,
the “Investment
Documents”).

    


    Unless otherwise defined in this
Guaranty, all capitalized terms when used herein shall have the same meaning as
is defined in the Securities Purchase Agreement.

    


    NOW, THEREFORE, as a material
inducement to each Investor to purchase the Notes from the Company and the
Warrants from Trestle, and for further good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the Guarantors hereby,
unconditionally, irrevocably and absolutely, warrant and represent to and
covenant with the Investors as follows:

    


    1.           Guaranty
of Obligation.  The Guarantors
jointly, severally, unconditionally, irrevocably and absolutely, guarantee to
the Investors that:

    


    (a) all indebtedness and other
obligations of the Company evidenced by or provided in the Note (the “Payment Obligation”)
and

    


    (b) each of the consummation of (i)
the “Trestle Reverse Split” (as defined in the Purchase Agreement), (ii) the
filing of an amended and restated certificate of incorporation of Trestle and
the Series A Preferred Stock Certificate of Designations (as defined) of Trestle
with the Secretary of State of the State of Delaware, (iii) the payment of
accrued interest on the Notes, and (iv) the delivery to each Investor of their
respective rights to shares of Series A Preferred Stock, all as required under
the Securities Purchase Agreement (collectively, the “Performance Obligations” and
together with the Payment Obligation, the “Guaranteed
Obligations”),

    


    will be
promptly paid when due and performed in accordance with the terms and provisions
thereof (and as they may be amended, extended or renewed from time to time)
including, without limitation, interest on all of the above amounts as agreed
upon between the Company and the Investors, and any and all renewals, extensions
and rearrangements of all or any part of the Guaranteed
Obligations.  This is a continuing guaranty and shall continue to
apply without regard to the form or amount of indebtedness or obligation which
the Company may create, renew, extend or alter in whole or in part, without
notice to the Guarantors.

    


    2.           Liability
for Other Indebtedness.  If the Guarantors
are or become liable for any indebtedness owing by the Company to any or all
Investors by endorsement or otherwise than under this Guaranty, such liability
shall not be in any manner impaired or affected hereby, and the rights of such
Investor hereunder shall be cumulative of any and all other rights that such
Investor may ever have against the Guarantors.  The exercise by such
Investor of any right or remedy hereunder or under any other instrument, or at
law or in equity, shall not preclude the concurrent or subsequent exercise of
any other right or remedy.


    
      
         


      

      
         


        
          

        

      

      
         


      

    


    3.           No
Release From Obligations.  The obligations,
covenants, agreements and duties of the Guarantors under this Guaranty shall not
be released or impaired in any manner whatsoever, without the written consent of
the Investors, including on account of any or all of the following:

    


    a.           any
permitted assignment, endorsement or transfer, in whole or in part, of the
Guaranteed Obligations, although made without consent of the
Guarantors;

     

    b.           any
waiver by any Investor of the performance or observance by either or both of the
Company or the Guarantors of any of the agreements, covenants, terms or
conditions contained in any document evidencing, governing or securing the
Guaranteed Obligations;

     

    c.           any
extension of the time for payment or performance of all or any portion of the
Guaranteed Obligations;

     

    d.           the
renewal, rearrangement, modification or amendment (whether material or
otherwise) of any duty, agreement or obligation of the Company set forth in any
document evidencing, governing or securing the Guaranteed
Obligations;

     

    e.           the
voluntary or involuntary liquidation, sale or other disposition of all or
substantially all of the assets of either or both of the Company or the
Guarantors;

     

    f.           any
receivership, insolvency, bankruptcy, reorganization or other similar
proceedings or lack of corporate power, affecting either or both of the Company
or the Guarantors or any of their assets;

     

    g.           any
release, withdrawal, surrender, exchange, substitution, subordination or loss of
any security or other guaranty at any time existing in connection with all or
any portion of the Guaranteed Obligations, or the acceptance of additional or
substitute property as security therefore;

     

    h.           the
release or discharge of the Company or the Guarantors from the observance or
performance of any agreement, covenant, term or condition contained in any
document evidencing, governing or securing the Guaranteed
Obligations;

     

    i.           any
action which the Investors may take or omit to take by virtue of any document
evidencing, governing or securing the Guaranteed Obligations or through any
course of dealing with either or both of the Company or the
Guarantors;

     

    j.           the
addition of a new guarantor or guarantors;

     

    k.           the
operation of law or any other cause, whether similar or dissimilar to the
foregoing;

     

    l.           any
adjustment, indulgence, forbearance or compromise that may be granted or given
by the Investors to any party;


    
      
         


      

      
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    m.           the
failure by the Investors to file or enforce a claim against the estate (either
in administration, bankruptcy or other proceeding) of the Company;

     

    n.           if
the recovery from the Company becomes barred by any statute of limitations or is
otherwise prevented;

     

    o.           any
defenses, set-offs or counterclaims which may be available to the
Company;

     

    p.           any
impairment, modification, change, release or limitation of liability of, or stay
of actions of lien enforcement proceedings against the Company, its property, or
its estate in bankruptcy resulting from the operation of any present or future
provision of the Bankruptcy Code or any other similar federal or state statute,
or from the decision of any court; or

     

    q.           any
neglect, delay, omission, failure or refusal of the Investors to take or
prosecute any action for the collection of any of the Guaranteed Obligations or
to foreclose or take or prosecute any action in connection with any lien, right
of security (including perfection thereof), existing or to exist in connection
with, or as security for, any of the Guaranteed Obligations, it being the
intention hereof that the Guarantors shall remain liable as principals on the
Guaranteed Obligations, notwithstanding any act, omission or thing which might,
but for the provisions hereof, otherwise operate as a legal or equitable
discharge of any Guarantor.

     

    4.           Payment
and Performance of Obligations.  In the event of
default by the Company in payment or performance of the Guaranteed Obligations,
or any part thereof, when such indebtedness or performance becomes due, either
by its terms or as the result of the exercise of any power to accelerate, the
Guarantors shall, without notice or demand, and without any notice having been
given to the Guarantors of the acceptance by any Investor of this Guaranty and
without any notice having been given to the Guarantors of the creating or
incurring of such indebtedness, pay the amount due thereon to each Investor, at
its office, or at such other place as may be designated in writing by such
Investor, and it shall not be necessary for any Investor, in order to enforce
such payment by the Guarantors, first, to institute suit or exhaust its remedies
against the Company or others liable on such indebtedness, or to enforce its
rights against any security which shall ever have been given to secure such
indebtedness.

    


    5.           Waiver of
Notice.  Notice to the
Guarantors of the acceptance of this Guaranty and of the making, renewing or
assignment of the Guaranteed Obligations and each item thereof, are hereby
expressly waived by the Guarantors.

    


    6.           Payments
by the Company.  Each payment on
the Guaranteed Obligations shall be deemed to have been made by the Company
unless express written notice is given to the Investors at the time of such
payment that such payment is made by the Guarantors as specified in such
notice.

    


    7.           Releases
and Waivers.  If all or any
part of the Guaranteed Obligations at any time be secured, the Guarantors agree
that the Investors may at any time and from time to time, at their discretion
and with or without valuable consideration, allow substitution or withdrawal of
collateral or other security and release collateral or other security without
impairing or diminishing the obligations of the Guarantors
hereunder.  The Guarantors further agree that if the Company executes
in favor of the Investors any collateral agreement, deed of trust or other
security instrument, the exercise by the Investors of any right or remedy
thereby conferred on the Investors shall be wholly discretionary with the
Investors, and that the exercise or failure to exercise any such right or remedy
shall in no way impair or diminish the obligations of the Guarantors
hereunder.  The Guarantors further agree that the Investors shall not
be liable for their failure to use diligence in the collection of the Guaranteed
Obligations or in preserving the liability of any person liable on the
Guaranteed Obligations, and the Guarantors hereby waive presentment for payment,
protest and notice thereof, notice of acceleration, and diligence in bringing
suits against any person liable on the Guaranteed Obligations, or any part
thereof.


    
      
         


      

      
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    8.           No
Release of the Guarantors.  If the Guaranteed
Obligations at any time exceeds the amount permitted by law, or the Company is
not liable because the act of creating the Guaranteed Obligations is ultra
vires, or the officers or persons creating the Guaranteed Obligations acted in
excess of their authority, and for these reasons the Guaranteed Obligations
which the Guarantors agree to pay cannot be enforced against the Company, such
fact shall in no manner affect the Guarantors’ liability hereunder, but the
Guarantors shall be liable under this Guaranty notwithstanding that the Company
is not liable for the Guaranteed Obligations, and to the same extent the
Guarantors would have been liable if the Guaranteed Obligations had been
enforceable against the Company.

    


    9.           Optional
Acceleration.  In the Event of
Default by the Company, as such term is defined in the Securities Purchase
Agreement, and if any such Event of Default shall occur at a time when any of
the Guaranteed Obligations may not then be due and payable, such Guaranteed
Obligations, at the option of the Investors, shall thereupon be deemed to be
immediately due and payable in full, and the Guarantors shall pay to the
Investors forthwith the full amount which would be payable hereunder if all
Guaranteed Obligations were then due and payable.

    


    10.           Successors
and Assigns.  This Guaranty is
for the benefit of the Investors, their permitted successors and assigns, and in
the event of an assignment by any Investor, its permitted successors or assigns,
of the Guaranteed Obligations, or any part thereof, the rights and benefits
hereunder, to the extent applicable to the indebtedness so assigned, may be
transferred with such indebtedness.

    


    11.           Modifications
and Waivers. Cumulative Rights.  No modification,
consent, amendment or waiver of any provision of this Guaranty, nor consent to
any departure by any Guarantor therefrom, shall be effective unless the same
shall be in writing and signed by an officer of each Investor and Guarantor, and
then shall be effective only in the specific instance and for the purpose for
which given.  No notice to or demand on the Guarantors in any case
shall, of itself, entitle the Guarantors to any other or further notice or
demand in similar or other circumstances.  No delay or omission by any
Investor in exercising any power or right hereunder shall impair any such right
or power or be construed as a waiver thereof or any acquiescence therein, nor
shall any single or partial exercise of any such power preclude other or further
exercise thereof, or the exercise of any other right or power
hereunder.  All rights and remedies of the Investors hereunder are
cumulative of each other and of every other right or remedy which the Investors
may otherwise have at law or in equity or under any other contract or document,
and the exercise of one or more rights or remedies shall not prejudice or impair
the concurrent or subsequent exercise of other rights or remedies.  In
this Guaranty, whenever the context so requires, the singular number includes
the plural, and conversely.

    


    12.           Compliance
with Laws.  Should the
Guarantors be permitted to raise usury as a defense under applicable law, then
no provision herein or in the Investment Documents shall require the payment or
permit the collection of interest in excess of the maximum permitted by
law.  Should such defense be available, the Guarantors shall not be
obligated to pay the amount of such interest to the extent that it is in excess
of the amount permitted by law as to the Guarantors.  Should the
Guarantors be permitted to raise the usury defense and prevail, the Investment
Documents shall be held subject to reduction of the interest charged to the
amount allowed under said usury laws as now or hereafter construed by the courts
having jurisdiction.  The parties agree that New York law shall
control as to this issue.


    
      
         


      

      
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    13.           Benefit
to Guarantor.  The Guarantors
acknowledge and warrant that they have derived or expect to derive financial and
other advantage and benefit, directly or indirectly, from the Guaranteed
Obligations and each and every advance thereof and from each and every renewal,
extension, release of collateral or other relinquishment of legal rights made or
granted or to be made or granted by the Investors to the Company.

    


    14.           Attorney's
Fees.  The Investors
shall be entitled to recover their reasonable attorneys’ fees and expenses in
the event of any dispute between the parties arising under this Agreement in
which the Investors are the prevailing party.

    


    15.           Guarantors'
Warranties.  Each Guarantor
hereby warrants and represents to each Investor that:

    


    a.           Such
Guarantor is duly organized, validly existing and in good standing under the
laws of its jurisdiction of organization, and is duly qualified and is in good
standing in each jurisdiction in which such qualification is required by law,
other than those jurisdictions as to which the failure to be so qualified or in
good standing could not, individually or in the aggregate, reasonably be
expected to have a material adverse effect.  Such Guarantor has the
corporate or other requisite power and authority to execute and deliver this
Guaranty and to perform the provisions hereof.

     

    b.           This
Guaranty has been duly authorized by all necessary action on the part of such
Guarantor, and this Guaranty constitutes a legal, valid and binding obligation
of such Guarantor enforceable against such Guarantor in accordance with its
terms.

     

    c.           The
execution, delivery and performance by such Guarantor of this Guaranty will not
(i) contravene, result in any breach of, or constitute a default under, or
result in the creation of any lien, claim or encumbrance in respect of any
property of such Guarantor under, any indenture, mortgage, deed of trust, loan,
purchase or credit agreement, lease, corporate charter or by-laws or other
organizational document, or any other agreement or instrument to which such
Guarantor is bound or by which such Guarantor or any of its properties may be
bound or affected, (ii) conflict with or result in a breach of any of the terms,
conditions or provisions of any order, judgment, decree, or ruling of any court,
arbitrator or governmental authority applicable to such Guarantor or (iii)
violate any provision of any statute or other rule or regulation of any
governmental authority applicable to such Guarantor.

     

    d.           No
consent, approval or authorization of, or registration, filing or declaration
with, any governmental authority is required in connection with the execution,
delivery or performance by such Guarantor of this Guarantee.

     

    e.           Upon
the execution and delivery hereof, such Guarantor will be solvent, will be able
to pay its debts as they mature and will have capital sufficient to carry on its
business.

     

    16.           Subordination
and No Subrogation.  If, for any
reason whatsoever, the Company now or hereafter becomes indebted to the
Guarantors, such indebtedness and all interest thereon, shall, at all times, be
subordinate in all respects to the Investment Documents, and the Guarantors
shall not be entitled to enforce or receive payment thereof until the Guaranteed
Obligations has been fully paid and satisfied.  Notwithstanding
anything to the contrary contained in this Guaranty or any payments made by the
Guarantors hereunder, the Guarantors shall not have any right of subrogation in
or under the Investment Documents or to participate in any way therein, or any
right, title or interest in and to any mortgaged property or any collateral for
the Guaranteed Obligations, all such rights of subrogation and participation
being hereby expressly waived and released, until the Guaranteed Obligations has
been fully paid and satisfied.


    
      
         


      

      
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    17.           Law
Governing and Jurisdiction. This Agreement shall be
enforced, governed by and construed in accordance with the laws of the State of
New York applicable to agreements made and to be performed entirely within such
state, without regard to the principles of conflict of laws.  The
parties hereto hereby submit to the exclusive jurisdiction of the United States
federal courts or New York state courts located in New York, New York with
respect to any dispute arising under this Agreement, the agreements entered into
in connection herewith or the transactions contemplated hereby or thereby, and
consent to the personal jurisdiction of such courts and shall subject themselves
to such personal jurisdiction.  The parties irrevocably waive the
defense of an inconvenient forum to the maintenance of such suit or
proceeding.  The parties further agree that service of process upon a
party mailed by first class mail shall be deemed in every respect effective
service of process upon the party in any such suit or
proceeding.  Nothing herein shall affect any party’s right to serve
process in any other manner permitted by law.  The parties agree that
a final non-appealable judgment in any such suit or proceeding shall be
conclusive and may be enforced in other jurisdictions by suit on such judgment
or in any other lawful manner.  The party which does not prevail in
any dispute arising under this Agreement shall be responsible for all fees and
expenses, including attorneys’ fees, incurred by the prevailing party in
connection with such dispute.

    


    18.           Severability.  If any provision
of this Guaranty or the application thereof to any person or circumstance shall,
for any reason and to any extent, be invalid or unenforceable, neither the
remainder of this Guaranty nor the application of such provision to any other
persons or circumstances shall be affected thereby, but rather the same shall be
enforced to the greatest extent permitted by law.

    


    19.           Paragraph
Headings.  The paragraph
headings inserted in this Guaranty have been included for convenience only and
are not intended, and shall not be construed, to limit or define in any way the
substance of any paragraph contained herein.

    


    20.           Facsimile
Signature.                                           This
Agreement may be executed and delivered to the Investor containing a facsimile
signature of [      ], the President of the
Guarantors; which facsimile signature each of the Guarantors acknowledges and
agrees shall have the same validity and enforceability as those the same were a
ribbon original signature.

    


    21.           Compounding
and Settlement.  The Guarantors
agree that Investor, in its discretion, may (i) bring suit against the
Guarantors and other guarantors, if any, jointly and severally or against any
one or more of them, (ii) compound or settle with any one or more of
guarantor(s) for such consideration as the Investor may deem proper, and (iii)
release one or more of guarantor(s) from liability hereunder, and that no such
action shall impair the rights of any Investor to collect the Guaranteed
Obligations (or the unpaid balance thereof) from the Guarantors, not so sued,
settled with or released.

    


    22.           Termination.  This
Guaranty shall terminate upon the Company’s repayment in full of the Guaranteed
Obligations; provided,
however, that this Guaranty shall continue to be effective or be
reinstated, as the case may be, if at any time payment of all, or any part
thereof, of the principal of or interest on any of the Obligations is rescinded
or must otherwise be restored by any Investor, whether under any bankruptcy or
insolvency proceeding or otherwise.

    


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    IN WITNESS WHEREOF, this Guaranty has
been duly executed by the undersigned on the date set forth above.

    

      
        
          
            
              
                
                  
                    
                      
                        
                          	
                                  GUARANTORS:

                                
	 
      
	
                                  TRESTLE
      HOLDINGS, INC.

                                
	
                                  (a
      Delaware corporation)

                                
	 
      
	
                                  By:

                                	 
      
	 
      
	
                                  MOQIZONE
      HOLDINGS LIMITED

                                
	
                                  (a
      Cayman Island corporation)

                                
	 
      
	
                                  BY:

                                	 
      
	 
      
	
                                  SHANGHAI
      MOQIZONE INFORMATION

                                
	
                                  TECHNOLOGY
      COMPANY LIMITED

                                
	
                                  (a
      corporation organized under the laws of the People’s Republic of
      China)

                                
	 
      
	
                                  By:

                                	 
      
	 
      
	
                                  BORROWER:

                                
	 
      
	
                                  MOBIZONE
      HOLDINGS LIMITED

                                
	
                                  (a
      Hong Kong corporation)

                                
	 
      
	
                                  By:

                                	 
      


                        

                      

                    

                  

                

              

            

          

        

      


      
        
           


        

        
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