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                                                                   Exhibit 10.25

                         FIRST AMENDED PROMISSORY NOTE

$800,000.00                                                   September 17, 2001
                                                             Fremont, California

     FOR VALUED RECEIVED, the undersigned, GILBERT C.P. HU (the "Employee") and
MAY K.R. HU (jointly and severally, the "Borrowers"), promise to pay to ALTIGEN
COMMUNICATIONS, INC., a Delaware corporation ("Lender"), at 47427 Fremont
Boulevard, Fremont, California, 94538 (or at such other place as Lender may from
time to time designate by written notice to Borrower), in lawful money of the
United States, the principal sum of Eight Hundred Thousand Dollars
($800,000.00), on the following terms:

     1. Payment:

        On September 30, 2001, the principal amount of Four Hundred Thousand
Dollars ($400,000.00) and all accrued interest shall be immediately due and
payable in lawful money of the United States. On September 30, 2002, the
principal amount of Four Hundred Thousand Dollars ($400,000.00) and all accrued
interest shall be immediately due and payable in lawful money of the United
States.

     2. Security: This Note is secured by: 602,927 shares of Common Stock of
Lender (as adjusted for any stock splits, stock dividends, recapitalizations and
the like) (the "Stock") and Borrowers' brokerage accounts (the "Accounts") with
Charles Schwab & Co., Inc. and Salomon Smith Barney (the "Collateral"). The
value of the Collateral shall not be a limitation of the collection of the full
amount of this Note from Borrowers, it being the express intention of the
Borrowers that this be a "full recourse" note and obligation.

     3. Maturity Event: In addition to the stated maturity dates set forth in
Paragraph 1 of this Note, upon the occurrence of a Maturity Event (as
hereinafter defined), the entire principal amount of the Loan and any other sum
due hereunder, shall become immediately due and payable without further demand
or notice to Borrowers. To the extent permitted by law, any of the following
events shall be a "Maturity Event" under this Note and the Deed of Trust:

          (a) Thirty (30) days after the date of a voluntary termination or
cessation of Employee's employment with the Lender.

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          (b) There shall occur any default in the performance of any obligation
of Borrowers contained in any deed of trust, security agreement or other
agreement (including any amendment, modification or extension thereof) which may
hereafter be executed by Borrowers for the purpose of securing this Note.

          (c) Borrowers (i) admit in writing inability to pay debts, (ii) make
an assignment for the benefit of creditors, (iii) file a voluntary petition in
bankruptcy, effect a plan or other arrangement with creditors, liquidate assets
under arrangement with creditors, or liquidate Borrowers' assets under court
supervision, (iv) have an involuntary petition in bankruptcy filed against him
or her that is not discharged within sixty (60) days after such petition is
filed, or (v) apply for or permit the appointment of a receiver or trustee or
custodian for any of Borrowers' property or assets which shall not have been
discharged within sixty (60) days after the date of appointment.

          (d) Any agreement or instrument executed in connection with this loan
proves to have been false or misleading.

          (e) Borrowers fail to execute, acknowledge and deliver the the
certificates evidencing the Stock or any other documents necessary to grant the
security interest in the Accounts concurrently with this Note.

          (f) Employee's death.

     4. Interest: Interest on the outstanding principal balance of this note
shall accrue at the rate of __________________________ (6.125%) per annum. Upon
the failure of Borrowers to pay the outstanding principal balance after a
Maturity Event, interest on the outstanding principal balance shall thereafter
accrue at the rate of seven and one-half percent (7.5%) per annum, or if lower,
the highest rate permitted by applicable law. Interest shall be calculated on
the basis of a three hundred sixty (360) day year consisting of twelve (12)
months, and shall compound annually.

     5. Borrower's Representations: Borrowers hereby make the following
representations and warranties to the Lender and acknowledges that Lender is
relying on such representations in making the loan:

          (a) Borrowers have not assigned, transferred any interest in, or
hypothecated any part of the Collateral.

          (b) The consent of no other person or entity is required to grant the
security interest in any part of the Collateral to the Lender.

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        (c) There are no actions, proceedings, claims or disputes pending or, to
the Borrowers' actual knowledge threatened against or affecting the Borrowers,
or any part of the Collateral.

     6. Borrower's Additional Obligations: Employee shall (a) procure, execute
and deliver from time to time any endorsements, assignments, financing
statements and other documents, instruments and agreements and take other
actions reasonably deemed necessary or appropriate by the Lender to perfect,
maintain and protect its lien against the Collateral and the priority thereof;
(b) appear in and defend any action or proceeding which may affect its title to
or the Lender's interest in the Collateral; (c) not surrender or lose possession
of (other than to the Lender), sell, encumber, lease, rent, or otherwise dispose
of or transfer any part of the Collateral or proceeds thereof (until the payment
of the portion of such proceeds required to be paid to the Lender pursuant to
this Agreement has been made) or right or interest therein and to keep the
Collateral free of all liens, and (d) not take any action contrary the purposes
of this Note

     7. Attorneys' Fees: In the event of Borrowers' default hereunder, Borrowers
shall pay all costs of collection, including reasonable attorneys' fees incurred
by the holder hereof on account of such collection, whether or not suit is filed
hereon.

     8. Waiver: The waiver by Lender of any breach of or default under any term,
covenant or condition contained herein or in any other agreement referred to
above shall not be deemed to be a waiver of any subsequent breach of or default
under the same or any other such term, covenant or condition.

     9. No Usury: Anything in this Note to the contrary notwithstanding, it is
expressly stipulated and agreed that the intent of Borrowers and Lender is to
comply at all times with all usury and other laws relating to this Note. If the
laws of the State of California would now or hereafter render usurious, or are
revised, repealed or judicially interpreted so as to render usurious, any amount
called for under this Note, or contracted for, charged or received with respect
to the loan evidenced by this Note, or if any prepayment by Borrowers results in
Borrowers having paid any interest in excess of that permitted by law, then it
is Borrowers' and Lender's express intent that all excess amounts theretofore
collected by Lender be credited to the principal balance of this Note (or, if
this Note has been paid in full, refunded to Borrowers), and the provisions of
this Note immediately be deemed reformed and the amounts therefor collectible
hereunder reduced, without the necessity of execution of any new document, so as
to comply with the then applicable law, but so as to permit the recovery of the
fullest amount otherwise called for hereunder.

     10. Prepayment: Borrowers may prepay all or any portion of this Note at any
time prior to the stated maturity date, with no premium or penalty.

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     11. Notice: This Note is subject to Section 2924(i) and 2966 of the
California Civil Code which provides that the holder of this Note shall give
written notice to Borrowers or their successors-in-interest, of prescribed
information (as set forth in said Civil Code Sections) as least ninety (90) days
and not more than one hundred and fifty (150) days before any Balloon Payment is
due.

     12. General Provisions: This Note shall be governed by and construed in
accordance with the laws of the State of California. Borrowers hereby waive
presentment for payment, protest and demand, notice of protest, demand and
dishonor and nonpayment of this Note, and consent that Lender may extend the
time for payment or otherwise modify the terms of payment or any part of the
whole of the debt evidenced by this Note, at the request of any person liable
hereon, and such consent shall not alter nor diminish the liability of any
person. Borrowers hereby waive the defense of the statute of limitations in any
action on this Note to the extent permitted by law.

     13. THIS NOTE, THE DEED OF TRUST AND ALL RELATED DOCUMENTATION ARE EXECUTED
VOLUNTARILY AND WITHOUT ANY DURESS OR UNDUE INFLUENCE ON THE PART OF OR ON
BEHALF OF THE PARTIES HERETO, WITH THE FULL INTENT OF CREATING THE OBLIGATIONS
AND SECURITY INTERESTS DESCRIBED HEREIN AND THEREIN. THE PARTIES ACKNOWLEDGE
THAT: (a) THEY HAVE READ SUCH DOCUMENTATION; (b) THEY HAVE BEEN REPRESENTED IN
THE PREPARATION, NEGOTIATION AND EXECUTION OF SUCH DOCUMENTATION BY LEGAL
COUNSEL OF THEIR OWN CHOICE OR THAT THEY HAVE VOLUNTARILY DECLINED TO SEEK SUCH
COUNSEL; (c) THEY UNDERSTAND THE TERMS AND CONSEQUENCES OF THIS NOTE, AND ALL
RELATED DOCUMENTATION AND THE OBLIGATIONS THEY CREATE; AND (d) THEY ARE FULLY
AWARE OF THE LEGAL AND BINDING EFFECT OF THIS NOTE, AND THE OTHER DOCUMENTS
CONTEMPLATED BY THIS AGREEMENT.


                                              AS BORROWERS:


                                              /s/ Gilbert C.P. Hu
                                              ---------------------
                                              Gilbert C.P. Hu


                                              /s/ May K.R. Hu
                                              ---------------------
                                              May K.R. Hu

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