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;

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 pa