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                                                                   EXHIBIT 10.66
                         Registration Rights Agreement

Issuer:  P-COM, INC.

Address: 3175 S. Winchester Blvd.
         Campbell, California 95008

Date:    January 14, 2000

THIS REGISTRATION RIGHTS AGREEMENT is entered into as of the above date by and
between SILICON VALLEY BANK ("Purchaser"), whose address is 3003 Tasman Drive,
Santa Clara, California  95054 and the above Company, whose address is set forth
above.

                                   RECITALS

     A.   Concurrently with the execution of this Agreement, the Purchaser is
purchasing from the Company a Warrant to Purchase Stock (the "Warrant") pursuant
to which Purchaser has the right to acquire from the Company the Shares (as
defined in the Warrant).

     B.   By this Agreement, the Purchaser and the Company desire to set forth
the registration rights of the Shares all as provided herein.

     NOW, THEREFORE, in consideration of the mutual promises, covenants and
conditions hereinafter set forth, the parties hereto mutually agree as follows:

     1.   Registration Rights.  The Company covenants and agrees as follows:

     1.1  Definitions.  For purposes of this Section 1:

     (a)  The term "register," "registered," and "registration" refer to a
registration effected by preparing and filing a registration statement or
similar document in compliance with the Securities Act of 1933, as amended (the
"Securities Act"), and the declaration or ordering of effectiveness of such
registration statement or document;

     (b)  The term "Registrable Securities" means (i) the Shares (if Common
Stock) or all shares of Common Stock of the Company issuable or issued upon
conversion of the Shares and (ii) any Common Stock of the Company issued as (or
issuable upon the conversion or exercise of any warrant, right or other security
which is issued as) a dividend or other distribution with respect to, or in
exchange for or in replacement of, any stock referred to in (i).

     (c)  The terms "Holder" or "Holders" means the Purchaser or qualifying
transferees under subsection 1.8 hereof who hold Registrable Securities.

     (d)  The term "SEC" means the Securities and Exchange Commission.

     1.2  Company Registration.

     (a)  Registration.  If at any time or from time to time, the Company shall
determine to register any of its securities, for its own account or the account
of any of its shareholders, other than with regard to resale registration
statements for the former holders of Series B Preferred Stock of the Company and
other than a registration on Form S-1 or S-8 relating solely to employee stock
option or purchase plans, or a registration on Form S-4 relating solely to an
SEC Rule 145 transaction, or a registration on any other form (other than
Form S-1, S-2, S-3 or S-18, or their successor forms) or any successor to such
forms, which does not include substantially the same information as would be
required to be included in a registration statement covering the sale of
Registrable Securities, the Company will:

     (i)  promptly give to each Holder written notice thereof (which shall
include a list of the jurisdictions in which the Company intends to attempt to
qualify such securities under the applicable blue sky or other state securities
laws); and

     (ii) include in such registration (and compliance), and in any underwriting
involved therein, all the Registrable Securities specified in a written request
or requests, made within 30 days after receipt of such written notice from the
Company, by any Holder or Holders, except as set forth in subsection 1.2(b)
below.

     (b)  Underwriting. If the registration of which the Company gives notice is
for a registered public offering involving an underwriting, the Company shall so
advise the Holders as a part of the written notice given pursuant to subsection
1.2(a)(i). In such event the right of any Holder to registration pursuant to
this subsection 1.2 shall be conditioned upon such Holder's participation in
such underwriting and the inclusion of such Holder's Registrable Securities in
the underwriting to the extent provided herein. All Holders proposing to
distribute their securities through such underwriting shall (together with the
Company and the other shareholders distributing their


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Silicon Valley Bank                                Registration Rights Agreement
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securities through such underwriting) enter into an underwriting agreement in
customary form with the underwriter or underwriters selected for such
underwriting by the Company. Notwithstanding any other provision of this Section
1.2(b), if the underwriter determines that marketing factors require a
limitation on the number of shares to be underwritten, the underwriter may
(subject to the allocation priority set forth below) exclude from such
registration and underwriting some or all of the Registrable Securities which
would otherwise be underwritten pursuant hereto. The Company shall so advise all
Holders of securities requesting registration, and the number of shares of
securities that are entitled to be included in the registration and underwriting
shall be allocated in the following manner. The number of shares that may be
included in the registration and underwriting on behalf of the Purchaser,
directors and officers and other Holders shall be allocated among the Purchaser,
directors and officers and other Holders in proportion, as nearly as
practicable, to the respective amounts of Registrable Securities and other
securities which they had requested to be included in such registration at the
time of filing the registration statement.

     1.3  Expenses of Registration. All expenses incurred in connection with any
registration, qualification or compliance pursuant to this Section 1 including
without limitation, all registration, filing and qualification fees, printing
expenses, fees and disbursements of counsel for the Company and expenses of any
special audits incidental to or required by such registration, shall be borne by
the Company except the Company shall not be required to pay underwriters' fees,
discounts or commissions relating to Registrable Securities or any fees and
disbursements of counsel for any Holder. All other expenses of any registered
offering not otherwise borne by the Company shall be borne pro rata among the
Holders participating in the offering and the Company.

     1.4  Registration Procedures. In the case of each registration,
qualification or compliance effected by the Company pursuant to this
Registration Rights Agreement, the Company will keep each Holder participating
therein advised in writing as to the initiation of each registration,
qualification and compliance and as to the completion thereof. Except as
otherwise provided in subsection 1.3, at its expense the Company will:

     (a)  Should a registration statement with respect to such Registrable
Securities become effective, upon the request of the Holders of a majority of
the Registrable Securities registered thereunder, keep such registration
statement effective for up to 120 days.

     (b)  Prepare and file with the SEC such amendments and supplements to such
registration statement and the prospectus used in connection with such
registration statement as may be necessary to comply with the provisions of the
Securities Act with respect to the disposition of all securities covered by such
registration statement.

     (c)  Furnish to the Holders such numbers of copies of a prospectus,
including a preliminary prospectus, in conformity with the requirements of the
Securities Act, and such other documents as they may reasonably request in order
to facilitate the disposition of Registrable Securities owned by them.

     (d)  Use its best efforts to register and qualify the securities covered by
such registration statement under such other securities or Blue Sky laws of such
states as shall be reasonably requested by the Holders, provided that the
Company shall not be required in connection therewith or as a condition thereto
to qualify to do business or to file a general consent to service of process in
any such states.

     (e)  In the event of any underwritten public offering, enter into and
perform its obligations under an underwriting agreement, in usual and customary
form, with the managing underwriter of such offering. Each Holder participating
in such underwriting shall also enter into and perform its obligations under
such an agreement.

     (f)  Notify each Holder of Registrable Securities covered by such
registration statement at any time when a prospectus relating thereto is
required to be delivered under the Securities Act or the happening of any event
as a result of which the prospectus included in such registration statement, as
then in effect, includes an untrue statement of a material fact or omits to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading in the light of the circumstances then
existing. Upon such notification, the Holders agree to cease immediately selling
Registrable Securities until the Company has provided a supplemental prospectus
to the Holders.

     1.5  Indemnification.

     (a)  The Company will indemnify each Holder of Registrable Securities and
each of its officers, directors and partners, and each person controlling such
Holder, with respect to which such registration, qualification or compliance has
been effected pursuant to this Rights Agreement, and each underwriter, if any,
and each person who controls any underwriter of the Registrable Securities held
by or issuable to such Holder, against all claims, losses, expenses, damages and
liabilities (or actions in respect thereto) arising out of or based on any
untrue statement (or alleged untrue statement) of a material fact contained in
any prospectus, offering circular or other document (including any related
registration statement, notification or the like) incident to any such
registration, qualification or compliance, or based on any omission (or alleged
omission) to state therein a material fact required to be stated therein or
necessary to make the statement therein not misleading, or any violation or
alleged violation by the Company of the Securities Act, the Securities Exchange
Act of 1934, as amended ("Exchange Act"), or any state securities law applicable
to the Company or any rule or regulation promulgated under the Securities Act,
the Exchange Act or any such state law and relating to action or inaction
required of the Company in connection with any such registration, qualification
of compliance, and will reimburse each such Holder, each of its officers,
directors and partners, and each person controlling such Holder, each such
underwriter and each person who controls any such underwriter, within a
reasonable amount of time after incurred for any reasonable legal and any other
expenses incurred in connection with investigating, defending or settling any
such claim, loss, damage, liability or action; provided, however, that the
indemnity agreement contained in this subsection 1.5(a) shall not apply to
amounts paid in settlement of any such claim, loss, damage, liability, or action
if such settlement is effected without the consent of

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Silicon Valley Bank                                Registration Rights Agreement
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the Company (which consent shall not be unreasonably withheld); and provided
further, that the Company will not be liable in any such case to the extent that
any such claim, loss, damage or liability arises out of or is based on any
untrue statement or omission based upon written information furnished to the
Company by such Holder specifically for use therein.

     (b)  Each Holder will, if Registrable Securities held by or issuable to
such Holder are included in the securities as to which such registration,
qualification or compliance is being effected, indemnify the Company, each of
its directors and officers, each underwriter, if any, of the Company's
securities covered by such a registration statement, each person who controls
the Company within the meaning of the Securities Act, and each other such
Holder, each of its officers, directors and partners and each person controlling
such Holder, against all claims, losses, expenses, damages and liabilities (or
actions in respect thereof) arising out of or based on any (i) sales not using
the official prospectus or using representations not in the official prospectus
or (ii) untrue statement (or alleged untrue statement) of a material fact
contained in any such registration statement, prospectus, offering circular or
other document, or any omission (or alleged omission) to state therein a
material fact required to be stated therein or necessary to make the statements
therein not misleading, and will reimburse the Company, such Holders, such
directors, officers, partners, persons or underwriters for any reasonable legal
or any other expenses incurred in connection with investigating, defending or
settling any such claim, loss, damage, liability or action, in each case to the
extent, but only to the extent, that such untrue statement (or alleged untrue
statement) or omission (or alleged omission) is made in such registration
statement, prospectus, offering circular or other document in reliance upon and
in conformity with written information furnished to the Company by such Holder
specifically for use therein; provided, however, that the indemnity agreement
contained in this subsection 1.5(b) shall not apply to amounts paid in
settlement of any such claim, loss, damage, liability or action if such
settlement is effected without the consent of the Holder (which consent shall
not be unreasonably withheld); and provided further, that the total amount for
which any Holder shall be liable under this subsection 1.5(b) shall not in any
event exceed the aggregate proceeds received by such Holder from the sale of
Registrable Securities held by such Holder in such registration.

     (c)  Each party entitled to indemnification under this subsection 1.5 (the
"Indemnified Party") shall give notice to the party required to provide
indemnification (the "Indemnifying Party") promptly after such Indemnified Party
has actual knowledge of any claim as to which indemnity may be sought, and shall
permit the Indemnifying Party to assume the defense of any such claim or any
litigation resulting therefrom; provided that counsel for the Indemnifying
Party, who shall conduct the defense of such claim or litigation, shall be
approved by the Indemnified Party (whose approval shall not be unreasonably
withheld), and the Indemnified Party may participate in such defense at such
party's expense; and provided further, that the failure of any Indemnified Party
to give notice as provided herein shall not relieve the Indemnifying Party of
its obligations hereunder, unless such failure resulted in prejudice to the
Indemnifying Party; and provided further, that an Indemnified Party (together
with all other Indemnified Parties which may be represented without conflict by
one counsel) shall have the right to retain one separate counsel, with the fees
and expenses to be paid by the Indemnifying Party, if representation of such
Indemnified Party by the counsel retained by the Indemnifying Party would be
inappropriate due to actual or potential differing interests between such
Indemnified Party and any other party represented by such counsel in such
proceeding. No Indemnifying Party, in the defense of any such claim or
litigation, shall, except with the consent of each Indemnified Party, consent to
entry of any judgment or enter into any settlement which does not include as an
unconditional term thereof the giving by the claimant or plaintiff to such
Indemnified Party of a release from all liability in respect to such claim or
litigation.

     1.6  Information by Holder. Any Holder or Holders of Registrable Securities
included in any registration shall promptly furnish to the Company such
information regarding such Holder or Holders and the distribution proposed by
such Holder or Holders as the Company may request in writing and as shall be
required in connection with any registration, qualification or compliance
referred to herein.

     1.7  Rule 144 Reporting.  With a view to making available to Holders the
benefits of certain rules and regulations of the SEC which may permit the sale
of the Registrable Securities to the public without registration, the Company
agrees at all times to:

     (a)  make and keep public information available, as those terms are
understood and defined in SEC Rule 144, after 90 days after the effective date
of the first registration filed by the Company for an offering of its securities
to the general public;

     (b)  file with the SEC in a timely manner all reports and other documents
required of the Company under the Securities Act and the Exchange Act (at any
time after it has become subject to such reporting requirements); and

     (c)  so long as a Holder owns any Registrable Securities, to furnish to
such Holder forthwith upon request a written statement by the Company as to its
compliance with the reporting requirements of said Rule 144 (at any time after
90 days after the effective date of the first registration statement filed by
the Company for an offering of its securities to the general public), and of the
Securities Act and the Exchange Act (at any time after it has become subject to
such reporting requirements), a copy of the most recent annual or quarterly
report of the Company, and such other reports and documents so filed by the
Company as the Holder may reasonably request in complying with any rule or
regulation of the SEC allowing the Holder to sell any such securities without
registration.

     1.8  Transfer of Registration Rights. Holders' rights to cause the Company
to register their securities and keep information available, granted to them by
the Company under subsections 1.2 and 1.7 may be assigned to a transferee or
assignee of a Holder's Registrable Securities not sold to the public, provided,
that the Company is given written notice by such Holder at the time of or within
a reasonable time after said transfer, stating the name and address of said
transferee or assignee and identifying the securities with respect to which such
registration rights are being assigned. The Company may prohibit the transfer of
any Holders' rights under this subsection 1.8 to any

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Silicon Valley Bank                                Registration Rights Agreement
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proposed transferee or assignee who the Company reasonably believes is a
competitor of the Company.

     2.   General.

     2.1  Waivers and Amendments.  With the written consent of the record or
beneficial holders of at least a majority of the Registrable Securities, the
obligations of the Company and the rights of the Holders of the Registrable
Securities under this agreement may be waived (either generally or in a
particular instance, either retroactively or prospectively, and either for a
specified period of time or indefinitely), and with the same consent the
Company, when authorized by resolution of its Board of Directors, may enter into
a supplementary agreement for the purpose of adding any provisions to or
changing in any manner or eliminating any of the provisions of this Agreement;
provided, however, that no such modification, amendment or waiver shall reduce
the aforesaid percentage of Registrable Securities.  Upon the effectuation of
each such waiver, consent, agreement of amendment or modification, the Company
shall promptly give written notice thereof to the record holders of the
Registrable Securities who have not previously consented thereto in writing.
This Agreement or any provision hereof may be changed, waived, discharged or
terminated only by a statement in writing signed by the party against which
enforcement of the change, waiver, discharge or termination is sought, except to
the extent provided in this subsection 2.1.

     2.2  Governing Law. This Agreement shall be governed in all respects by the
laws of the State of California as such laws are applied to agreements between
California residents entered into and to be performed entirely within
California.

     2.3  Successors and Assigns. Except as otherwise expressly provided herein,
the provisions hereof shall inure to the benefit of, and be binding upon, the
successors, assigns, heirs, executors and administrators of the parties hereto.

     2.4  Entire Agreement. Except as set forth below, this Agreement and the
other documents delivered pursuant hereto constitute the full and entire
understanding and agreement between the parties with regard to the subjects
hereof and thereof.

     2.5  Notices. etc. All notices and other communications required or
permitted hereunder shall be in writing and shall be mailed by first class mail,
postage prepaid, certified or registered mail, return receipt requested,
addressed (a) if to Holder, at such Holder's address as set forth in the heading
to this Agreement, or at such other address as such Holder shall have furnished
to the Company in writing, or (b) if to the Company, at the Company's address
set forth in the heading to this Agreement, or at such other address as the
Company shall have furnished to the Holder in writing.

     2.6  Severability. In case any provision of this Agreement shall be
invalid, illegal, or unenforceable, the validity, legality and enforceability of
the remaining provisions of this Agreement or any provision of the other
Agreements shall not in any way be affected or impaired thereby.

     2.7  Titles and Subtitles. The titles of the sections and subsections of
this Agreement are for convenience of reference only and are not to be
considered in construing this Agreement.

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Silicon Valley Bank                                Registration Rights Agreement
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     2.8  Counterparts.  This Agreement may be executed in any number of
counterparts, each of which shall be an original, but all of which together
shall constitute one instrument.

                                   Company:

                                        P-COM, INC.



                                        By /s/ Karl F. Meyer
                                          -------------------------------------
                                           Vice President, Corporate Controller




                                   Purchaser:

                                        SILICON VALLEY BANK


                                        By /s/ Patrick J. Clemens
                                          ------------------------------

                                        Title Vice President
                                             ---------------------------

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