Exhibit 10.1

                                 FIRST AMENDMENT
                                       TO
                           LOAN AND SECURITY AGREEMENT

         This FIRST AMENDMENT to Loan and Security Agreement (this "Amendment")
is entered into this 1st day of August, 2005, by and between Silicon Valley Bank
("Bank") and Castelle, a California corporation ("Borrower") whose address is
855 Jarvis Drive Suite 100, Morgan Hill, CA 95037.

                                    RECITALS

         A. Bank and Borrower have entered into that certain Loan and Security
Agreement dated as of August 2, 2004 (as the same may from time to time be
amended, modified, supplemented or restated, the "Loan Agreement"). Bank has
extended credit to Borrower for the purposes permitted in the Loan Agreement.

         B. Bank has extended credit to Borrower for the purposes permitted in
the Loan Agreement.

         C. Borrower has requested that Bank amend the Loan Agreement to (1)
extend the maturity date and (2) waive the testing of deposit requirement
covenant from April 1, 2005 through October 31, 2005.

         D. Bank has agreed to so amend certain provisions of the Loan
Agreement, but only to the extent, in accordance with the terms, subject to the
conditions and in reliance upon the representations and warranties set forth
below.

                                    AGREEMENT

         NOW, THEREFORE, in consideration of the foregoing recitals and other
good and valuable consideration, the receipt and adequacy of which is hereby
acknowledged, and intending to be legally bound, the parties hereto agree as
follows:

1. Definitions. Capitalized terms used but not defined in this Amendment shall
have the meanings given to them in the Loan Agreement.

2.       Amendments to Loan Agreement.

2.1 Section 2.3 (Interest Rate, Payments). Section 2.3(b) is amended in part to
provide that interest due on the Committed Revolving Line is payable on the last
day of each month.

2.2 Section 6.6 (Primary Accounts). Notwithstanding anything to the contrary set
forth in Section 6.6, Borrower shall not be required to be in compliance with
the deposit requirement covenant from April 1, 2005 through October 31, 2005.

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2.3 Section 13 (Definitions). The following term and its respective definition
set forth in Section 13.1 is amended in its entirety and replaced with the
following:

                  "Revolving Maturity Date" is July 31, 2006.

3.       Limitation of Amendments.

3.1 The amendments set forth in Section 2, above, are effective for the purposes
set forth herein and shall be limited precisely as written and shall not be
deemed to (a) be a consent to any amendment, waiver or modification of any other
term or condition of any Loan Document, or (b) otherwise prejudice any right or
remedy which Bank may now have or may have in the future under or in connection
with any Loan Document.

3.2 This Amendment shall be construed in connection with and as part of the Loan
Documents and all terms, conditions, representations, warranties, covenants and
agreements set forth in the Loan Documents, except as herein amended, are hereby
ratified and confirmed and shall remain in full force and effect.

4. Representations and Warranties. To induce Bank to enter into this Amendment,
Borrower hereby represents and warrants to Bank as follows:

4.1 Immediately after giving effect to this Amendment (a) the representations
and warranties contained in the Loan Documents are true, accurate and complete
in all material respects as of the date hereof (except to the extent such
representations and warranties relate to an earlier date, in which case they are
true and correct as of such date), and (b) no Event of Default has occurred and
is continuing;

4.2 Borrower has the power and authority to execute and deliver this Amendment
and to perform its obligations under the Loan Agreement, as amended by this
Amendment;

4.3 The organizational documents of Borrower delivered to Bank on the Effective
Date remain true, accurate and complete and have not been amended, supplemented
or restated and are and continue to be in full force and effect;

4.4 The execution and delivery by Borrower of this Amendment and the performance
by Borrower of its obligations under the Loan Agreement, as amended by this
Amendment, have been duly authorized;

4.5 The execution and delivery by Borrower of this Amendment and the performance
by Borrower of its obligations under the Loan Agreement, as amended by this
Amendment, do not and will not contravene (a) any law or regulation binding on
or affecting Borrower, (b) any contractual restriction with a Person binding on
Borrower, (c) any order, judgment or decree of any court or other governmental
or public body or authority, or subdivision thereof, binding on Borrower, or (d)
the organizational documents of Borrower;

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4.6 The execution and delivery by Borrower of this Amendment and the performance
by Borrower of its obligations under the Loan Agreement, as amended by this
Amendment, do not require any order, consent, approval, license, authorization
or validation of, or filing, recording or registration with, or exemption by any
governmental or public body or authority, or subdivision thereof, binding on
either Borrower, except as already has been obtained or made; and

4.7 This Amendment has been duly executed and delivered by Borrower and is the
binding obligation of Borrower, enforceable against Borrower in accordance with
its terms, except as such enforceability may be limited by bankruptcy,
insolvency, reorganization, liquidation, moratorium or other similar laws of
general application and equitable principles relating to or affecting creditors'
rights.

5. Counterparts. This Amendment may be executed in any number of counterparts
and all of such counterparts taken together shall be deemed to constitute one
and the same instrument.

6. Effectiveness. This Amendment shall be deemed effective upon (a) the due
execution and delivery to Bank of this Amendment by each party hereto and (b)
Borrower's payment of an amendment fee in an amount equal to $4,000.


         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed and delivered as of the date first written above.


BANK                                                    BORROWER

SILICON VALLEY BANK                                     CASTELLE


By:    ________________________                  By:   _________________________
Name:  ________________________                  Name: _________________________
Title: ________________________                  Title:_________________________



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