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                                                                     EXHIBIT 4.9

                              OCCAM NETWORKS, INC.
                               77 Robin Hill Road
                         Santa Barbara, California 93117

                                  March 8, 2004

Alta Partners
One Embarcadero Center
Suite 4050
San Francisco, CA 94111
Attn: Khaled Nasr

     Re:  Board Rights of Alta Partners
          -----------------------------
Ladies and Gentlemen:

     This letter agreement is being entered into by Occam Networks, Inc., a
Delaware corporation, ("Occam"), Alta California Partners III, L.P., and Alta
Embarcadero Partners III, LLC (collectively, "Alta") to clarify and confirm the
parties' understanding and agreement with respect to the matters set forth
below. In consideration of Alta's purchase of 400,000 shares of Occam's Series
A-2 Preferred Stock (the "Shares") pursuant to the Series A-2 Preferred Stock
Purchase Agreement dated as of November 19, 2003 (as amended pursuant to
Amendment No. 1 thereto of even date herewith) and the mutual covenants and
agreements set forth below, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, Occam and Alta hereby
agree as follows:

     1.   Board Rights.

          (a)  Right to Require Nomination of Alta Designee. Occam agrees to
provide the Alta Observer (as defined herein) with 30 days' advance written
notice of Occam's intent to file with the Securities and Exchange Commission any
proxy statement or information statement pursuant to which Occam intends to
solicit stockholders with respect to the election of members (a "Stockholder
Solicitation") of Occam's Board of Directors (the "Board"); provided, however,
that in the event the Alta Observer is present at any meeting of the Board for
which proper notice has been delivered to Alta in accordance herewith and at
which the nomination of directors is approved in connection with a Stockholder
Solicitation, no such written notice shall be required. Within five business
days of the Alta Observer's receipt of such notice, or the date of such meeting
of the Board, as the case may require, Alta may request in a written notice to
Occam and each member of the Board that Occam nominate for election to the Board
a single member to be designated by Alta in writing (the "Alta Designee"). Any
Alta Designee shall be reasonably acceptable to Occam and the Board. In
connection with any nomination pursuant to this Section 1(a), Occam agrees to
nominate the Alta Designee for election to the Board, to include such nomination
in any materials relating to such Stockholder Solicitation, and otherwise to
take all commercially reasonable actions within Occam's authority to cause the
election of, and to maintain, the Alta Designee as a member of the Board.

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Alta Partners
March 8, 2004
Page 2

          (b)  Right to Appoint Director. Alta may, at any time and upon a
request in writing delivered to Occam and each member of the Board, request that
the Board appoint an Alta Designee to the Board. In the event of the delivery of
such a written request, Occam agrees to take all commercially reasonable actions
within its authority (i) to cause the Alta Designee to be appointed to the
Board; (ii) thereafter to cause the nomination of the Alta Designee in
connection with any subsequent Stockholder Solicitation relating to the election
of directors; (iii) to recommend in connection with any subsequent Stockholder
Solicitation relating to the election of directors that stockholders of Occam
vote for the election of the Alta Designee; and (iv) otherwise to maintain the
status of the Alta Designee as a member of the Board.

          (c)  Observer Rights. In the event there is no Alta Designee serving
as a member of the Board, Alta may designate one representative of Alta (the
"Alta Observer"), who shall be reasonably acceptable to Occam and the Board, to
attend meetings of the Board in a non-voting, observer capacity. Occam shall (i)
provide the Alta Observer with copies of all notices, minutes, consents,
information, and other materials (collectively, the "Materials") that Occam
provides to all its directors, when and as such Materials are delivered to
members of the Board (and in the same manner in which such Materials are
delivered to members of the Board), and (ii) shall allow the Alta Observer to
attend all meetings of the Board in a non-voting observer capacity.
Notwithstanding the foregoing, Occam shall not be required to provide the Alta
Observer with Materials, and the Alta Observer may be excluded from access to
any meeting of the Board or any portion thereof, if (i) in the judgment of
counsel to Occam, it would adversely affect attorney-client privilege with
respect to any matter; (ii) the Board proposes to discuss a matter in which Alta
would have a conflict of interest (other than solely as a result of Alta's being
a stockholder and other than relating to a transaction in which any member of
the Board is similarly conflicted, unless such conflicted Board member has
agreed to recuse himself or herself from such discussion); or (iii) it would
result in a violation by Occam of a confidentiality agreement with a third party
or otherwise result in an unpermitted disclosure of confidential information of
a third party that Occam is required to hold in confidence.

     2.   Confidentiality Obligations of Alta. Alta acknowledges and agrees that
Alta and the Alta Observer will, as a result of this agreement, receive
"material nonpublic information" relating to Occam (as such term is contemplated
by the Securities Exchange Act of 1934, as amended (the "Exchange Act")), and
the rules and regulations promulgated thereunder (including, without limitation,
Regulation FD)). Alta further acknowledges and agrees that Regulation FD
prohibits Occam from disclosing to a holder of Occam's securities any material
nonpublic information under circumstances in which it is reasonably foreseeable
that such holder will purchase or sell Occam's securities on the basis of such
information, unless such holder has expressly agreed to maintain the disclosed
information in confidence. Accordingly, Alta agrees not to disclose and to
maintain in confidence any Occam Confidential Information (as defined herein)
that it may receive, to disclose Occam Confidential Information within Alta only
to those employees, partners, shareholders, members, or agents of Alta who have
a reasonable "need to know" such Occam Confidential Information, and to cause
the Alta Observer and any such employee, partner, shareholder, member, or agent
of Alta to whom Occam Confidential

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Alta Partners
March 8, 2004
Page 3

Information may have been disclosed to maintain such Occam Confidential
Information in confidence in accordance with this agreement. For purposes of
this agreement, Occam Confidential Information shall include (i) any information
contained in writing in the Materials or otherwise obtained by Alta or the Alta
Observer through participation at meetings of the Board that would reasonably be
expected to be "material nonpublic information" of Occam pursuant to Regulation
FD and (ii) any information relating to Occam that may be disclosed orally or in
writing to Alta, the Alta Observer, the Alta Designee, or any employee, partner,
shareholder, member, or agent of Alta that would reasonably be expected to be
"material nonpublic information" of Occam pursuant to Regulation FD. Occam
Confidential Information shall not include any information that (i) has been
released publicly by Occam or (ii) that is or becomes publicly known through no
wrongful act of Alta. Alta further agrees not to engage in any transaction in
the Company's securities while in possession of any information concerning Occam
that would be deemed material nonpublic information or any transaction that
would otherwise result in any violation of the Exchange Act or any rule or
regulation promulgated thereunder.

     3.   Notices. All notices or other communications required or permitted to
be given hereunder shall be made in writing and sent postage prepaid by
certified mail, return receipt requested, by recognized overnight courier
service, or by facsimile, addressed to the party to be notified as follows:

     If to Occam:             Occam Networks, Inc.
                              77 Robin Hill Road
                              Santa Barbara, CA 93117
                              Attn: Chief Financial Officer
                              Facsimile: (805) 692-2999

     with a copy to:          Wilson Sonsini Goodrich & Rosati, P.C.
                              650 Page Mill Road
                              Palo Alto, CA 94304
                              Attn: Robert F. Kornegay
                              Facsimile: (650) 493-6811

     If to Alta:              Alta Partners
                              One Embarcadero Center, Suite 4050
                              San Francisco, CA 94111
                              Attn: Khaled Nasr
                              Facsimile: (415) 362-6178

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Alta Partners
March 8, 2004
Page 4

     with a copy to:          Morrison & Foerster, LLP
                              425 Market Street
                              San Francisco, CA 94105-2482
                              Attn: John W. Campbell
                              Facsimile: (415) 268-7522

     Each such notice or communication shall for all purposes of this agreement
be treated as effective or having been given when delivered personally, or if
sent by certified mail, at the earlier of its receipt or 72 hours after the same
has been deposited in a regularly maintained receptacle for deposit of the
United States mail, addressed and mailed as aforesaid, or, if sent by facsimile
transmission, upon confirmation of receipt. A party may, by written notice,
designate a different address for notices or different or additional persons to
be notified.

     4.   Termination. This agreement shall terminate and be of no further force
or effect upon the earlier to occur of (i) such time as Alta or its affiliates
(as defined in Rule 12b-2 promulgated under the Exchange Act) no longer hold at
least 200,000 Shares (or (A) a number of shares of Occam's Common Stock issued
upon conversion of 200,000 Shares or (B) any combination of Shares and Occam's
Common Stock issued upon conversion of Shares representing at the time of
issuance at least 200,000 Shares), and (ii) the closing of a reorganization,
consolidation, merger or similar transaction involving Occam in which the
stockholders of Occam, immediately prior to such closing, hold, immediately
after such closing, less than a majority of the outstanding voting securities of
the surviving or successor entity or its parent.

     5.   Miscellaneous Provisions. Alta may not assign its rights under this
agreement without the prior written consent of Occam. The invalidity or
unenforceability of any one provision of this agreement shall not affect the
validity or enforceability of any other provision of this letter agreement. This
agreement shall not be modified except by written agreement of each of Alta and
Occam. This agreement may be executed in two or more counterparts, each of which
shall be deemed an original and all of which together shall constitute one and
the same instrument. This agreement shall be governed by the laws of the State
of California without reference to the conflicts of law provisions thereof.

                  [Remainder of Page Intentionally Left Blank]

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Alta Partners
March 8, 2004
Page 5

Please indicate Alta's acceptance of this agreement by countersigning this
letter below.

                                          Very truly yours,

                                          OCCAM NETWORKS, INC.


                                          By: /s/ Robert L. Howard-Anderson
                                              ----------------------------------
                                              Robert L. Howard-Anderson
                                              President and Chief Executive
                                              Officer

AGREED AND ACCEPTED:

ALTA CALIFORNIA PARTNERS III, L.P.


By:  Alta California Management
     Partners III, LLC


By: /s/ Khaled Nasr
    ----------------------------------
    Director

ALTA EMBARCADERO PARTNERS III, LLC


By:  /s/ Hilary Strain
     ---------------------------------
     V.P. of Finance and Administration

    [Signature Page to Occam/Alta Board Rights and Confidentiality Agreement]