Exhibit 10.28

DISTRIBUTOR AGREEMENT

AGREEMENTmade as of the 12 day of June, 2003, by and between AltiGen Communications, Inc., a
corporation duly organized and existing under the laws of the State of Delaware, with its principal office at 47427 Fremont Blvd., Fremont, California 94538, hereinafter called the "Supplier" and
GRAYBAR ELECTRIC COMPANY, INC., a corporation duly organized and existing under the laws of the State of New York, with its principal office at 34 North Meramec Avenue, St. Louis, Missouri
63105 (Post Office Box 7231, St. Louis, Missouri 63177), hereinafter called "Graybar".

WITNESSETH:

WHEREAS,the Supplier is desirous of appointing Graybar a non-exclusive distributor, and Graybar is
desirous of accepting such appointment,

NOW, THEREFORE,in consideration of the premises and the mutual covenants and agreements herein contained, Supplier hereby appoints
Graybar its non-exclusive distributor and Graybar accepts appointment for the sale of products or material (hereinafter "Material") furnished by Supplier under this Agreement.

1. TERRITORY; AUTHORIZED RESELLERS.This appointment applies throughout the United States, Canada, and Mexico. Graybar may
resell Material only to resellers included in the list of authorized resellers provided by Supplier and updated by Supplier as changes are made.

2. TITLE AND SHIPPING.Title to all Material covered by this Agreement shall pass to Graybar upon delivery at the destination
designated by Graybar and shall be at the risk of Supplier until title thereto
shall have passed as herein provided. Routing of shipments may be specified by Graybar when Graybar is liable for transportation charges. Graybar is liable for all costs relating to transportation and
delivery. Graybar has transportation insurance, and Altigen will not provide duplicate coverage. Transportation costs prepaid by Supplier and added to Graybar's invoice will be at the lowest net cost
after applying all negotiated discounts obtained by Supplier from shipper.

3. PRICE.All purchases of Material made by Graybar shall be upon the current terms and prices established by Supplier, as
stated in the Altigen Distributor Price List attached hereto as Exhibit A and incorporated herein by reference, and updated from time to time. Furthermore, Graybar shall be given written notice
** days in advance of the effective date of any price change. Such notice shall be sent to the attention of the Manager, Price/Cost Services at the principal office listed above and shall include
actual unit costs to Graybar (and suggested selling prices, if applicable).

In
the event of an increase in the price of said Material for which orders shall have been placed by Graybar, Graybar may, at its option, cancel such orders in whole or in part within **
days after receipt of notice of such price increase described in the previous paragraph.

Price Protection.In the event of a decrease in Material pricing, Graybar shall be credited with an amount equal to the
difference between the price charged for such Material and the new and reduced price for any such Material in Graybar's inventory or in transit to Graybar as of the effective date of the price
decrease. To obtain price protection, within ** days of receipt of Supplier's notice of the price decrease, Graybar shall provide to Supplier a written report of (i) inventory on hand and
(ii) inventory in transit from Supplier, showing by part number the quantity of each Supplier Material in Graybar's inventory and in transit as of the effective date of the price decrease.
Price protection will not be granted in the case of special promotion.

1

---

3A. TAXES.The prices referred to in this Agreement do not include taxes and other similar charges. Graybar is responsible
for, and shall pay or reimburse Supplier for, all taxes, including sales, use, value-added (VAT), general services (GST), gross receipts, excise, personal property, or other federal, state or local
taxes, export taxes and import duties, or any similar assessments based on the sale to Graybar of Material, maintenance, or other services provided under this Agreement, and any penalties, interest
and collection or withholding costs associated with any of the foregoing items, excluding taxes on Supplier's net worth and net income.Tax Exemption.
Graybar may provide Supplier with a tax exemption certificate acceptable to the taxing authorities in lieu of paying such taxes. Graybar shall reimburse Supplier for any fines, penalties, taxes and
other charges, including expenses incurred by Supplier, due to Graybar's submission of invalid information.

4. TERMS OF PAYMENT.Net ** Proximo, which means that all invoices received in a calendar month are paid on the ** day of the
following calendar month. The maximum time to pay is therefore ** days and the minimum time to pay is ** days, with an average of ** days.

5. GENERAL INDEMNITY; EXCLUSION OF CONSEQUENTIAL OR SPECIAL DAMAGES.

5.1 Indemnity by SupplierNotwithstanding disclaimers of liability for consequential or special damages contained in
Section 5.4 ("No Non-Direct Damages") or in Supplier's warranty to the contrary and provided Supplier is notified promptly and given authority, information and assistance for the
defense of same, Supplier agrees to defend and hold Graybar harmless from all claims and suits made or brought against Graybar by any third party for consequential or special damages arising from
Material purchased by Graybar hereunder except claims or suits: (i) arising from the negligence or intentional misconduct of Graybar, its employees, or agents or servants of either of them; or
(ii) to the extent based upon any material deviation between a warranty expressly extended by Graybar to any such customer and Supplier's warranty given to Graybar.

5.2 Indemnity by Graybar.Notwithstanding the disclaimers of liability for consequential, special, and non-direct
damages contained in Section 5.4 ("No Non-Direct Damages"), Graybar agrees to indemnify and hold Supplier harmless from any claims, suits, proceedings, losses, liabilities, damages,
costs and expenses (inclusive of Supplier's reasonable attorneys' fees) for bodily injury or property damage, including consequential or special damages relating thereto, made against or incurred by
Supplier as a result of negligence, misrepresentation, or error or omission on the part of Graybar or representative of Graybar.

Graybar
shall be solely responsible for any warranties or representations made by Graybar or Graybar's employees or agents which differ from the warranty provided by Supplier in its
end-user agreement which Supplier includes with each Material sold hereunder.

5.3 Third-Party Claims.Neither party shall be liable for any claim by the other party based on any third-party claim except
as expressly authorized in Section 5.1 ("Indemnity by Supplier"), Section 5.2 ("Indemnity by Graybar"), Section 7 ("Patent and Trademark Indemnification") and in Section 9
("Environmental Liability") of this Agreement.

5.4 No Non-Direct Damages.EXCEPT AS EXPRESSLY STATED TO THE CONTRARY HEREIN, TO THE FULL EXTENT ALLOWED BY LAW
THE PARTIES SHALL NOT BE LIABLE TO EACH OTHER FOR ANY CLAIM, WHETHER BASED IN CONTRACT, TORT (INCLUDING NEGLIGENCE), OR ANY OTHER LEGAL THEORY, FOR INCIDENTAL, CONSEQUENTIAL, INDIRECT, SPECIAL OR
PUNITIVE DAMAGES OF ANY KIND, OR FOR LOSS OF REVENUE OR PROFITS, LOSS OF BUSINESS, LOSS OF INFORMATION OR DATA, OR ANY DAMAGES THAT ARE NOT DIRECT, ARISING OUT OF OR IN CONNECTION WITH THIS AGREEMENT
OR THE PERFORMANCE OR BREACH HEREOF, EVEN IF THE PARTY HAS BEEN ADVISED OF THE POSSIBILITY THEREOF.

2

---

5.5 Validity.THESE DISCLAIMERS AND LIMITATIONS OF LIABILITY WILL NOT BE AFFECTED IF ANY REMEDY PROVIDED HEREIN FAILS OF ITS
ESSENTIAL PURPOSE.

6. PURCHASE ORDERS AND SUPPLY.Purchase orders will be deemed accepted by Supplier unless rejected within two
(2) business days of receipt. Requested shipment date must comply with Supplier's stated lead-time, which will not exceed two (2) weeks. Supplier will make every reasonable
effort to furnish a sufficient quantity of said Material to meet the resale requirements of Graybar. Supplier may decline to make shipments to Graybar if Graybar is delinquent in making payments to
Supplier.

6A. MONTHLY POINT-OF-SALE AND INVENTORY REPORTS.

6A.1 Point-of-Sale Report.During the term of this Agreement, Graybar shall provide to Supplier a
monthly report containing the following information: (i) the authorized reseller's account number, (ii) authorized reseller's name, (iii) the "ship to" destination zip code and
(iv) the part number and Graybar's cost of the Material shipped. Such report, with respect to a calendar month, shall be delivered to Supplier no later than the tenth (10th) day of the
following calendar month.

6A.2 Monthly Inventory Report.Within ten (10) days after the end of each month during the term of this Agreement,
Distributor shall provide Supplier with an inventory report.

7. PATENT AND TRADEMARK INFRINGEMENT.

7.1 Defense.Supplier hereby warrants that all of the Material sold hereunder by it to Graybar, its successors or assigns,
are and will be as of the date of shipment by Supplier free and clear of infringement of any patent valid in the United States, Canada, or Mexico, or any trademark registered in the United States,
Canada, or Mexico. Supplier agrees to defend any and all actions and suits alleging any infringement of any patent valid in the United States, Canada, or Mexico, or any trademark registered in the
United States, Canada, or Mexico (regardless of whether such patent or trademark was in effect on the date of shipment of the Material) that may at any time be brought against Graybar, or its
successors or assigns, or any of its or their customers, to pay all costs and expenses incurred with Supplier's prior written authorization, and to satisfy all final judgments and decrees against the
defendant or defendants or settlement agreed to by Supplier in such actions or suits, but Supplier shall not be liable for any settlement incurred by Graybar without Supplier's prior written
authorization; provided that (i) the Supplier shall have prompt written notice of the commencement of any such action or suit, (ii) Graybar gives Supplier the right to control and direct
the investigation, and preparation, and full opportunity to defend and settle such action or suit, through counsel of Supplier' choice; and (iii) Graybar gives Supplier assistance and full
cooperation for the defense of such action or suit.

7.2 Exclusions.The provisions of the foregoing indemnity shall not apply with respect to any instances of alleged
infringement based upon or arising out of the use of such Material in any manner for which the Material was not designed, or for use of Material other than the uses and distributions designated by
Supplier, for use of any Material that has been modified by Graybar or any third party, or for use of any Material in connection with or in combination with any equipment, devices or software that
have not been supplied by Supplier, unless such connection or combination arises from standard, expected telephony usage. Notwithstanding any other provisions hereof, the foregoing indemnity shall not
apply with respect to any infringement based on Graybar's activities occurring subsequent to its receipt of notice of any claimed infringement or activities in violation of written instructions given
to Graybar by Supplier, unless Supplier shall have given Graybar written permission to continue to market and distribute the allegedly infringing Material.

7.3 Supplier's Solutions.If Material is, or in Supplier's opinion might be, held to infringe as set forth above, Supplier
may, at its option and expense, replace or modify such Material so as to avoid

3

---

infringement,
or procure the right for Graybar to continue the use and resale of such Material. If neither of such alternatives is, in Supplier's opinion, reasonably possible, the infringing Material
shall be returned to Supplier, and Supplier's sole liability, in addition to its obligation to reimburse any awarded damages, costs and expenses set forth above, shall be to refund the purchase price
paid for such Material by Graybar. Supplier is not obligated to accept new orders for Materials which are subject to a Claim covered under this Section.

7.4 ** Remedy.THIS SECTION STATES **' ** RESPONSIBILITY AND LIABILITY TO **, AND **'S ** REMEDY FROM **, FOR ANY CLAIMS
AGAINST ** FOR ACTUAL OR ALLEGED INFRINGEMENT OR MISAPPROPRIATION OF ANY INTELLECTUAL PROPERTY RIGHT BY ANY MATERIAL ** HEREUNDER OR **, AND IS IN ** AND ** OTHER EXPRESS, IMPLIED OR STATUTORY
WARRANTIES, TERMS, OR CONDITIONS TO ** REGARDING
INFRINGEMENT AND MISAPPROPRIATION. ** may ** only to ** ** obligations as stated here in this Section 7, but may not obligate ** to provide any additional intellectual property **.

8. PRODUCT LIABILITY INSURANCE.Supplier will furnish Graybar with a Certificate of Insurance evidencing Product Liability
Coverage with protection extending to Graybar under a Vendors Endorsement. Such insurance shall cover all Material sold by Supplier to Graybar and shall be maintained in companies reasonably
acceptable to Graybar with minimum limits of liability of $** combined single limit per occurrence with a policy aggregate of $**.

9. ENVIRONMENTAL LIABILITY.For purposes of this Agreement, "Hazardous Substances" shall be defined as any Material that:
(a) is a hazardous substance as defined under U.S. federal or state law; or (b) includes any extremely hazardous substance; toxic substance or chemical; radioactive material; petroleum;
oil; asbestos-containing material; or any other contaminant or pollutant. If any of the Material to be sold hereunder is considered a Hazardous Substance, or might otherwise be subject to regulation
under any environmental, health or safety laws or regulations, Supplier will notify Graybar in writing prior to the purchase of such Material and will provide, in accordance with applicable law,
instructions on the proper use, handling and disposal of the Material, in the form of a Material Safety Data Sheet (MSDS). Within ** days after receipt of notice that the Material to be purchased
contains Hazardous Substances, Graybar may, at its option, cancel such orders.

Supplier
shall, at its own expense, defend or settle any claim, suit, or proceeding ("Claim") that is instituted against Graybar, its successors, assigns, agents or employees
("Indemnitees") by a third party to the extent such Claim arises out of or is in any way related to any environmental contamination, injury or damage to natural resources or property, or injury to or
death of persons, resulting from or related to (i) the release, spilling, leaking, or discharging of any Hazardous Substance by the Material or packaging provided by Supplier, when used in
accordance with Supplier's instructions and disposed of in accordance with legal requirements, or (ii) liability resulting from dumping, use, storage, treatment, or disposal of the Material or
packaging in accordance with instructions provided by Supplier in the MSDS; except to the extent caused by the negligence or willful misconduct of any Indemnitee, or by the negligence or willful
misconduct of any third party, and Supplier shall pay all damages awarded therein against any Indemnitee or agreed upon in settlement by Supplier. This indemnity is conditioned upon the Indemnitee
(i) giving Supplier prompt notice in writing of any covered Claim or threat thereof, (ii) permitting Supplier sole control, through counsel of Supplier's choice, to defend and/or settle
such Claim; and (iii) giving Supplier all the needed information, assistance and authority, at Supplier's expense, to enable Supplier to defend or settle such Claim.

10. LIMITED WARRANTY; REPAIR OR REPLACEMENT.

10.1 AltiGen Communications Material Warranty.Supplier warrants the Material TO END USERS ONLY pursuant to the terms and
conditions of the End-User Agreement and no warranty is

4

---

extended
to Graybar. Supplier's End-User Agreement is included with each unit of Material, and must be passed through by Graybar, unchanged.

10.2 Warranty Procedures.Supplier will repair or replace, at its own expense,, for a period of one year from the date of
purchase by Graybar's customer or by the end user, any parts of the Material manufactured by Supplier or sold by it which parts do not substantially conform to Supplier's end-user warranty
when used for the intended purposes. Defective Material may be returned by Graybar's customer or by the end user, or by Graybar provided Graybar obtains a Returned Material Authorization (RMA) number
prior to accepting the return from its customer. The customer pays transportation charges to return the defective Material to Supplier, and Supplier pays transportation charges to ship the replaced or
repaired Material to the customer. If neither repair nor replacement is reasonably available, Supplier may, in its sole discretion, refund to the customer who submitted the defective Material the
purchase price paid for the defective Material. All Material and parts that are replaced will become the property of Supplier. Replacement Material or parts may be new or reconditioned. Supplier
warrants any replaced or repaired Material or part for ninety (90) days from shipment, or the remainder of the initial warranty period, whichever is longer. Should Supplier's warranty exceed
one year, then such longer term is applicable. In the event of "out of box" failures, the warranty procedures stated above apply.

10.3 Limitations and Disclaimer.EXCEPT FOR THE EXPRESS WARRANTY SET FORTH IN THE END-USER AGREEMENT, AND THE
EXPRESS WARRANTY OF NON-INFRINGEMENT STATED IN SECTION 7.1 ("PATENT AND TRADEMARK INFRINGEMENT DEFENSE") SUPPLIER EXPRESSLY DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, EITHER IN
FACT OR BY OPERATION OF LAW, STATUTORY OR OTHERWISE, OR ARISING FROM THE COURSE OF DEALING BETWEEN THE PARTIES OR USAGE OF TRADE, INCLUDING WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE.

10.4NO PERSON IS AUTHORIZED TO MAKE ANY OTHER WARRANTY OR REPRESENTATION BINDING UPON SUPPLIER CONCERNING THE PERFORMANCE OF
THE MATERIAL OTHER THAN AS PROVIDED IN THE END-USER AGREEMENT. GRAYBAR SHALL MAKE NO OTHER WARRANTY, EXPRESS OR IMPLIED, ON BEHALF OF SUPPLIER.

10.5 Toll FraudGraybar is forbidden from stating or implying that Supplier Material provides immunity from fraudulent
intrusion ("Toll Fraud").

10A GRAYBAR'S WARRANTY.Graybar hereby represents and warrants to Supplier that neither this Agreement (nor any term hereof)
nor the performance of or exercise of rights under this Agreement, is restricted by, contrary to, in conflict with, ineffective under, requires registration or approval or tax withholding under, or
affects Supplier's intellectual property rights (or the duration thereof) under, or will require any compulsory licensing under, any law or regulation of any organization, country, group of countries
or political or governmental entity to which Graybar is subject.

10B EXPORT COMPLIANCE.Graybar agrees not to export, either directly or indirectly, the Material or any documentation related
thereto without first obtaining any required license or other approval from the U.S. Department of Commerce or any other agency or department of the United States Government. If Graybar exports any
Material or related documentation from the United States or re-exports any Material or related documentation from a foreign destination, Graybar shall ensure that the
export/re-export or import of the Material and related documentation is in compliance with all laws, regulations, orders or other restrictions of the United States and the appropriate
foreign government.

5

---

11. STOCK BALANCING PROGRAM.Supplier recognizes that from time to time, it may be necessary for Graybar, in order to
properly perform its obligations hereunder, to reduce, exchange or eliminate certain Material from its inventory. Accordingly, Supplier shall allow quarterly returns with no restocking charges
provided Graybar prepays associated freight and insurance costs and subject to all of the following conditions:



Supplier
will issue a credit memo for the returned Material in the amount of the lesser of (i) current price as stated in the Altigen Distributor Price List or (ii) the price invoiced to
and actually paid by Graybar less any rebates and price protection.

12. NON-ASSIGNABILITY.This agreement shall not be transferable or assignable by either party hereto without the
written consent of the other party, which may not be unreasonably delayed or withheld. Until such written consent is obtained, the party transferring or assigning this agreement shall not be relieved
of the obligations hereunder.

13. TERMINATION.The distributorship hereby created may be terminated only (a) by an agreement in writing duly signed
by the parties hereto; or (b) by either party at will, with or without cause, upon not less than ninety (90) days' notice in writing given by certified mail or other method allowed by
Section 24 ("Notices") to the other party; (c) by either party if the other party commits a material breach of any obligation hereunder which is not cured within thirty (30) days'
after issuance of written notice to the breaching party, which notice shall state the breach upon which termination is based, or (d) by either party hereto upon one (1) day's like notice
in the event the other party hereto attempts to assign this Agreement or any rights thereunder without the other party's written consent, or either party ceases to function as a going concern or to
conduct its operations in the normal course of business, or a receiver is appointed or applied for by the party, or a petition under the Federal Bankruptcy Act is filed by or against either party, or
either party makes an assignment for the benefit of creditors. Termination shall not relieve Graybar of the obligation to pay all sums due hereunder.

14. REPURCHASE AFTER TERMINATION.Within thirty (30) days after the termination of the distributorship hereby created,
(a) if Graybar terminates for convenience or Supplier terminates for Graybar's breach or bankruptcy, Supplier may, at its option, repurchase from Graybar any or all Material and all repair and
replacement parts therefor which are new and unused of which Graybar is then the owner, at the net price paid by Graybar, or at Supplier's then current net price to distributors generally, whichever
is lower, Graybar to bear all return transportation costs; or (b) if Supplier terminates for convenience or Graybar terminates for Supplier's breach or bankruptcy, then Supplier shall be
obligated to repurchase all of the Material and all the repair and replacement parts from Graybar at the said price set forth above, the Supplier to bear all return transportation costs.

15. DELIVERIES AFTER TERMINATION.After a date for termination of the distributorship hereby created shall have been
established by notice or agreement, the Supplier shall be obligated to deliver, and Graybar shall be obligated to accept, such of the Material as Graybar shall have ordered from the Supplier prior to
the date for termination; provided, however, that in no event shall the Supplier be obligated to deliver, or Graybar be obligated to accept, any of such Material after the date of such termination.

6

---

16. SALES AFTER TERMINATION.The acceptance of any order from, or the sale of any Material to, Graybar after the termination
of the distributorship hereby created shall not be construed as a renewal or extension thereof nor as a waiver of termination, but in the absence of a new written Agreement, all such transactions
shall be governed by provisions identical with the provisions of this Agreement.

17.NO LIABILITY FOR TERMINATION.Neither party shall, by reason of
termination of distributorship of said Material, be liable to the other for compensation, reimbursement or damages on account of the loss of prospective profits on anticipated sales, or on account of
expenditures, investments, leases or commitments in connection with the business or goodwill of the other. The foregoing shall not affect either party's claim for damages arising out of any breach
which led to such termination.

18.FAILURE TO ENFORCE.The failure of either party to enforce at any time,
or for any period of time, the provisions hereof shall not be construed to be a waiver of such provisions unless accompanied by a clear written statement that such provision is waived. A waiver of any
default hereunder or of any of the terms and conditions of this Agreement shall not be deemed to be a continuing waiver or a waiver of any other default or of any other term or condition, or a waiver
of the right of such party thereafter to enforce each and every such provision.

19.ENTIRE AGREEMENT; NO ORAL AGREEMENTS.This Agreement is intended as the
complete, final and exclusive statement of the terms of the agreement between the parties and supersedes all prior understandings, writings, proposals, representations or communications, oral or
written, relating to the subject matter hereof. Although Graybar may use its standard purchase order and other forms, and Supplier may use its standard order acknowledgment and invoice, the terms and
conditions of this Agreement will prevail over such forms, and any inconsistent, conflicting or different terms in such forms will be of no effect. Except where unilateral modification is specifically
authorized herein, any amendments to this Agreement must be in writing and executed by both parties.

20.TERMINATION OF PRIOR AGREEMENTS.This Agreement terminates and supersedes
all prior Agreements between the parties, except those listed below which shall continue in full force and effect:

Exceptions:
None

21. HEADINGS.Headings of this Agreement are inserted solely for the purpose of convenience of reference and are in no manner
to be construed as a part of the Agreement.

22. RELATIONSHIP OF THE PARTIES.The parties shall at all times during the term of this Agreement act as, and shall represent
themselves to be, independent contractors, and not an agent,
partner, joint venturer, or employee of the other party. Neither party will have the right to enter into any contracts or binding commitments in the name of the other party or on such other party's
behalf.

23. FORCE MAJEURE.Neither party shall be liable to the other party for the failure to perform any of its obligations
hereunder (other than the payment of money) resulting from acts of the other party, acts of civil or military authority, governmental priorities, earthquake, fire, flood, epidemic, quarantine, energy
interruptions, strike, labor trouble, war, riot, accident, shortage, delay in transportation, or any other causes beyond the reasonable control of the party whose performance is delayed.

24. NOTICES.Notices shall be given in writing to the address stated immediately below, or to such other address as shall be
given by either party to the other in writing. Any notice involving breach or termination shall be sent by recognized overnight courier or by certified mail, return receipt requested. All other
notices may additionally be sent by fax or e-mail with an automatic confirmation

7

---

of
transmission by the transmitting machine. All notices shall be deemed to have been given and received on the earlier of actual delivery (except that faxes and e-mails sent on a
non-business day will be deemed received on the next business day) or three (3) days from the date of postmark.

To Graybar:

To Supplier:Graybar Electric Company, Inc.

AltiGen Communications, Inc.34 N. Meramec Ave

47427 Fremont Blvd.Clayton, MO 63105

Fremont, CA 94538Attn: David Bender

Attn: Philip M. McDermott, CFOe-mail: david.bender@gbe.com

e-mail: pmcdermott@altigen.comFax: 314-573-9288

Fax: 510/252-9738Telephone: 314-573-9318

Telephone: 510/580-7904


25. SEVERABILITY.In the event any provision of this Agreement is found to be invalid, illegal or unenforceable, a modified
provision shall be substituted which carries out as nearly as possible the original intent of the parties, and the validity, legality and enforceability of any of the remaining provisions shall not in
any way be affected or impaired thereby.

26. GOVERNING LAW.THIS AGREEMENT SHALL BE CONSTRUED IN ACCORDANCE WITH, AND ALL DISPUTES HEREUNDER SHALL BE GOVERNED BY, THE
LAWS OF THE STATE OF CALIFORNIA, EXCLUDING ITS CONFLICT OF LAWS RULES. The United Nations Convention on Contracts for the International Sale of Goods (1980) is hereby excluded in its entirety from
application to this Agreement.

27. SURVIVAL.The following sections will survive expiration or termination of this Agreement:



8

---



IN WITNESS WHEREOF,the parties hereto have caused these presents to be executed by a duly authorized officer on the date(s) shown below,
to be effective as of the day and year first above written.

|                                                                           |  |                                                                                 
|-------------------------------------------------------------------------- |  | --------------------------------------------------------------------------------
|ALTIGEN COMMUNICATIONS, INC.Supplier                                       |  | GRAYBAR ELECTRIC COMPANY, INC.                                                  
|                                                                           |  |                                                                                 
|/s/PHILIP MCDERMOTTSignature (Vice) President (CFO)                        |  | /s/RICHARD D. OFFENBACHERSignature (Vice) President                             
|                                                                           |  |                                                                                 
|Philip McDermottType or print name of person whose signature appears above |  | Richard D. OffenbacherType or print name of person whose signature appears above
|                                                                           |  |                                                                                 
|June 12, 2003Date                                                          |  | August 27, 2003Date                                                             

SG-930 (10/01)

9

---

Exhibit A
Graybar / AltiGen Distributor Agreement

Effective June 12, 2003

|AltiGen Communications, Inc.
Distributor Price List |  | LOGO
|--------------------------------------------------- |  | ----

|Part Number               |                                 | Description |                                                                                                    |  |          | Price
|------------------------- | ------------------------------- | ----------- | -------------------------------------------------------------------------------------------------- |  | -------- | -----
|AltiServ Office           |                                 |             |                                                                                                    |  |         
|                          | ALTI-SERV1-IP                   |             | 08x04x12 AltiServ1 IP-PBX Solution w/ AltiWare v4.6, 8 Alti-IP 600 Phones, and 16 Station Licenses |  |          |      
|                          | ALTI-SERV2-IP                   |             | 00x00x12 AltiServ2 IP-PBX Solution w/AltiWare v4.6 and 12 Station Licenses                         |  | Note: 17 |      
|                          | ALTI-OFFICE1A                   |             | 04x08 AltiServ Small Office Solution w/ AltiWare OE v4.6 and 12 Station License                    |  |          |      
|                          | ALTI-OFFICE2A-R                 |             | 00x24 AltiServ Office Solution w/ AltiWare OE v4.6 and 24 Station License                          |  |          |      
|                          | ALTI-OFFICE3-R                  |             | 24x36 AltiServ Office Solution w/ AltiWare OE v4.6 and 36 Station License                          |  |          |      
|Alti-IP 600 IP Phone      |                                 |             |                                                                                                    |  |         
|                          | ALTI-IP600                      |             | Alti-IP 600 IP Phone                                                                               |  |          |      
|AltiWare Telephony Boards |                                 |             |                                                                                                    |  |         
|                          | ALTI-CD0408UD-SPH001            |             | CID Quantum Platform, 4 trunks & 8 extensions. Rev. D                                              |  | Note: 1  |      
|                          | ALTI-CD0804UD-SPH001            |             | CID Quantum Platform, 8 trunks & 4 extensions. Rev. D                                              |  | Note: 1  |      
|                          | ALTI-CD0012UD-SPH001            |             | CID Quantum Platform, 12 extensions. Rev. D                                                        |  | Note: 1  |      
|                          | ALTI-TTAS-12                    |             | PCI Analog Station Board, 12 extensions                                                            |  | Note: 2  |      
|                          | ALTI-TTRS-12                    |             | Triton Resource Board with 12 session support                                                      |  | Note: 3  |      
|                          | ALTI-TTAT-12                    |             | PCI 12 port Analog Trunk BoardLoopstart Only                                                      |  | Note: 7  |      
|                          | ALTI-TTAT-12GS                  |             | PCI 12 port Analog Trunk BoardLoopstart / Groundstart                                             |  | Note: 7  |      
|                          | ALTI-T1E1-1                     |             | Triton T1 / E1 Board (4.0i and 4.5 and above for E1)                                               |  | Note:12  |      
|                          | ALTI-TTT1-1                     |             | Triton T1/PRI Board                                                                                |  |          |      
|                          | ALTI-TTIP-8                     |             | Triton VoIP Board with 8 / 12 ports                                                                |  | Note: 4  |      
|                          | ALTI-30IPLIC460                 |             | 30-Port G.711 upgrade license for ALTI-TTIP-8                                                      |  | Note: 8  |      
|                          | AltiWare Software               |             |                                                                                                    |  |          |      
|                          | ALTI-OE460E                     |             | AltiWare Open Edition (OE) Release 4.6                                                             |  | Note:11  |      
|                          | v4.6 AltiWare Station Licensing |             |                                                                                                    |  |          |      
|                          | ALTI-OELIC460-012               |             | AltiWare OE 4.612 Station Licenses                                                                |  |          |      
|                          | ALTI-OELIC460-024               |             | AltiWare OE 4.624 Station Licenses                                                                |  |          |      
|                          |                                 |             |                                                                                                    |  |          |      

10

---

|                                    | ALTI-OELIC460-048                                            |  | AltiWare OE 4.648 Station Licenses                                                              |  |          |  | $ | **
|----------------------------------- | ------------------------------------------------------------ |  | ------------------------------------------------------------------------------------------------ |  | -------- |  | - | --
|                                    | ALTI-OELIC460-072                                            |  | AltiWare OE 4.672 Station Licenses                                                              |  |          |  | $ | **
|                                    | v4.6 AltiWare Software Options                               |  |                                                                                                  |  |          | 
|                                    | ALTI-ACOLIC460                                               |  | AltiConsole 4.6 License Key                                                                      |  | Note: 22 |  | $ | **
|                                    | ALTI-AVWLIC460                                               |  | AltiView 4.6 License Key                                                                         |  | Note: 22 |  | $ | **
|                                    | ALTI-CRALIC460                                               |  | AltiServ Call Router Advanced w/ Queue Announcements                                             |  |          |  | $ | **
|                                    | v4.6 AltiWare Contact Center Software                        |  |                                                                                                  |  |          | 
|                                    | ALTI-ACCLIC460                                               |  | AltiServ Contact Center(ACC) Optional Call Center for AltiServ                                   |  | Note: 15 |  | $ | **
|                                    | ALTI-AGSLIC460-01                                            |  | 1 AltiServ Contact Center(ACC) Agent Seat                                                        |  | Note: 16 |  | $ | **
|                                    | ALTI-AGSLIC460-05                                            |  | 5 AltiServ Contact Center ACC Agent Seats                                                        |  | Note: 16 |  | $ | **
|                                    | ALTI-AGSLIC460-10                                            |  | 10 AltiServ Contact Center ACC Agent Seats                                                       |  | Note: 16 |  | $ | **
|                                    | ALTI-AGCLIC460-01                                            |  | 1 AltiServ Contact Center ACC AltiAgent client Session                                           |  | Note: 16 |  | $ | **
|                                    | ALTI-AGCLIC460-05                                            |  | 5 AltiServ Contact Center ACC AltiAgent client Sessions                                          |  | Note: 16 |  | $ | **
|                                    | ALTI-AGCLIC460-10                                            |  | 10 AltiServ Contact Center ACC AltiAgent client Sessions                                         |  | Note: 16 |  | $ | **
|                                    | ALTI-SPCLIC460-01                                            |  | 1 AltiServ Contact Center ACC AltiSupervisor client Session                                      |  | Note: 16 |  | $ | **
|                                    | ALTI-SPCLIC460-05                                            |  | 5 AltiServ Contact Center ACC AltiSupervisor clients Sessions                                    |  | Note: 16 |  | $ | **
|                                    | v4.6 AltiWare Upgrades from OE 4.0 and higher                |  | Note: 9                                                                                          |  |          | 
|                                    | ALTI-OE460E-UP-012                                           |  | AltiWare OE 4.6 Upgrade for 12 Station Licenses                                                  |  |          |  | $ | **
|                                    | ALTI-OE460E-UP-024                                           |  | AltiWare OE 4.6 Upgrade for 24 Station Licenses                                                  |  |          |  | $ | **
|                                    | ALTI-OE460E-UP-048                                           |  | AltiWare OE 4.6 Upgrade for 48 Station Licenses                                                  |  |          |  | $ | **
|                                    | ALTI-OE460E-UP-072                                           |  | AltiWare OE 4.6 Upgrade for 72 Station Licenses                                                  |  |          |  | $ | **
|                                    | v4.6 AltiWare Software Option Upgrades from OE4.0 and higher |  | Note: 9                                                                                          |  |          | 
|                                    | ALTI-ACOLIC460-UP                                            |  | AltiConsole 4.6 Upgrade                                                                          |  |          |  | $ | **
|                                    | ALTI-AVWLIC460-UP                                            |  | AltiView 4.6 Upgrade                                                                             |  |          |  | $ | **
|                                    | ALTI-ACCLIC460-UP                                            |  | AltiServ Contact Center 4.6 Upgrade                                                              |  |          |  | $ | **
|v4.0a AltiWare Licensing            |                                                              |  |                                                                                                  |  |         
|                                    | ALTI-OELIC-012                                               |  | AltiWare OE 4.0a12 Station Licenses                                                             |  |          |  | $ | **
|                                    | ALTI-OELIC-024                                               |  | AltiWare OE 4.0a24 Station Licenses                                                             |  |          |  | $ | **
|                                    | ALTI-OELIC-048                                               |  | AltiWare OE 4.0a48 Station Licenses                                                             |  |          |  | $ | **
|                                    | ALTI-OELIC-072                                               |  | AltiWare OE 4.0a72 Station Licenses                                                             |  |          |  | $ | **
|v4.0a AltiServ Software Options     |                                                              |  |                                                                                                  |  |         
|                                    | ALTI-ACO400AE                                                |  | AltiConsole 4.0a For OE 4.0a only                                                                |  |          |  | $ | **
|                                    | ALTI-CTR400AE                                                |  | AltiWare Center 4.0a For OE 4.0a only                                                            |  |          |  | $ | **
|                                    | ALTI-AVW400AE                                                |  | AltiView 4.0a For OE 4.0a client software                                                        |  | Note: 5  |  | $ | **
|                                    | AltiContact Manager Product                                  |  |                                                                                                  |  |          | 
|AltiContact Manager Starter Package |                                                              |  |                                                                                                  |  |         
|                                    | ACM-PLATFORM                                                 |  | ACM IP-Contact Center Solution w/ 12 Agent, 12 AltiAgent sessions, and 1 AltiSupervisor session. |  |          |  | $ | **
|                                    |                                                              |  |                                                                                                  |  |          |  |  

11

---

|            | AltiContact Manager Business User Licensing |  |                                                              |  |          | 
|----------- | ------------------------------------------- |  | ------------------------------------------------------------ |  | -------- | 
|            | ACM-ACBLIC460-01                            |  | ACM 1 Business User License                                  |  | Note: 21 | 
|            | ACM-ACBLIC460-12                            |  | ACM 12 Business User License                                 |  | Note: 21 | 
|            | ACM-ACBLIC460-24                            |  | ACM 24 Business User License                                 |  | Note: 21 | 
|            | ACM-ACBLIC460-48                            |  | ACM 48 Business User License                                 |  | Note: 21 | 
|            | ACM-ACBLIC460-72                            |  | ACM 72 Business User License                                 |  | Note: 21 | 
|            | ACM Contact Center Expansion Software       |  |                                                              |  |          | 
|            | ACM-AGSLIC460-01                            |  | 1 ACM Agent Seat                                             |  | Note: 18 | 
|            | ACM-AGSLIC460-05                            |  | 5 ACM Agent Seats                                            |  | Note: 18 | 
|            | ACM-AGSLIC460-10                            |  | 10 ACM Agent Seats                                           |  | Note: 18 | 
|            | ACM-AGSLIC460-20                            |  | 20 ACM Agent Seats                                           |  | Note: 18 | 
|            | ACM-AGCLIC460-01                            |  | 1 ACM AltiAgent client session                               |  | Note: 18 | 
|            | ACM-AGCLIC460-05                            |  | 5 ACM AltiAgent client sessions                              |  | Note: 18 | 
|            | ACM-AGCLIC460-10                            |  | 10 ACM AltiAgent client sessions                             |  | Note: 18 | 
|            | ACM-AGCLIC460-20                            |  | 20 ACM AltiAgent client sessions                             |  | Note: 18 | 
|            | ACM-SPCLIC460-01                            |  | 1 ACM AltiSupervisor client session                          |  | Note: 18 | 
|            | ACM-SPCLIC460-05                            |  | 5 ACM AltiSupervisor client sessions                         |  | Note: 18 | 
|            | ACM-SPCLIC460-10                            |  | 10 ACM AltiSupervisor client sessions                        |  | Note: 18 | 
|            | ACM-SPCLIC460-20                            |  | 20 ACM AltiSupervisor client sessions                        |  | Note: 18 | 
|            | ACM-RECLIC460-01                            |  | 1 ACM Centralized Recording Seat                             |  | Note: 20 | 
|            | ACM-RECLIC460-05                            |  | 5 ACM Centralized Recording Seats                            |  | Note: 20 | 
|            | ACM-RECLIC460-10                            |  | 10 ACM Centralized Recording Seats                           |  | Note: 20 | 
|            | ACM Software Options                        |  |                                                              |  |          | 
|            | ACM-CRALIC460                               |  | ACM Call Router Advanced w/ Queue Announcements              |  |          | 
|            | ACM-WEBLIC460                               |  | ACM AltiWeb                                                  |  | Note: 19 | 
|            | ALTI-ACOLIC460                              |  | AltiConsole 4.6                                              |  | Note: 22 | 
|            | ALTI-AVWLIC460                              |  | AltiView 4.6                                                 |  | Note: 22 | 
|Peripherals |                                             |  |                                                              |  |         
|            | CBL-25M50-01                                |  | DB25 to 50-pin Telco cable, Male to Male                     |  |          | 
|            | CBL-MVIP22-01                               |  | MVIP cable with 22 connectors                                |  |          | 
|            | CBL-P12DC-06                                |  | 6 connector, PC to 12Vdc power supply cable for ALTI-TTAS-12 |  |          | 
|            | DOC-RFG01-04                                |  | 4 User Pocket Reference Guides                               |  |          | 
|            | DOC-ICM01-400                               |  | Installation Configuration & Maintenance Manual (OE 4.0a)    |  |          | 
|            | DOC-ICM01-460                               |  | Installation Configuration & Maintenance Manual (OE 4.6)     |  |          | 
|            | DOC-ACMICM-460                              |  | Installation Configuration & Maintenance Manual (ACM)        |  |          | 
|            | DOC-AVWMAN460                               |  | 8 AltiView User Guides in one package (OE 4.6)               |  |          | 
|            | DOC-CTRMAN-400                              |  | 8 Center 4.0a User Guides in one package                     |  |          | 
|            | DOC-ATCMAN-460                              |  | 8 AltiClient User Manual in one package                      |  |          | 
|            | MSC-PANEL-02                                |  | 12 Port Connection Panel with 50-pin F Telco connector       |  |          | 
|            | ALTI-PIF4                                   |  | 4 port Power Influence Filter                                |  |          | 
|            |                                             |  |                                                              |  |          | 

12

---

| | ALTI-RF0012        |  | RF Filter 12 Ports                                                                     |  |          |  | $ | **
| | ------------------ |  | -------------------------------------------------------------------------------------- |  | -------- |  | - | --
| | ALTI-E1-BALUN      |  | E1 7 Ohm DIN 1.6/5.6 coax to 120 twisted pair BALUN                                    |  | Note: 10 |  | $ | **
| | Not for Resale Kit |  |                                                                                        |  |          | 
| | ALTI-NFR4600       |  | Dealer Demo KitsOE 4.6, AltiConsole, ACC, 12 port station board, 12-port VoIP card    |  |          |  | $ | **
| | ALTI-NFR460Q       |  | Dealer Demo KitsOE 4.6, AltiConsole, ACC, 4x8 analog Quantum board, 12-port VoIP card |  |          |  | $ | **
| | ALTI-NFRLIC-460A   |  | Optiion OE Demo ACC, AltiConsole, Call Router                                          |  | Note: 13 |  | $ | **

---

Notes:

13

---

QuickLinks