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                                                                    EXHIBIT 4.4

                          REGISTRATION RIGHTS AGREEMENT


         This Registration Rights Agreement (this "Agreement") is entered into
as of this 26th day of September, 2001, by and between Nucentrix Broadband
Networks, Inc., a Delaware corporation (the "Company"), and Blake Twedt, a
resident of 10224 Oasis Palm Drive, Tampa, Florida 33615, and John Dudeck, a
resident of 11672 Harborside Circle, Largo, Florida 33773 (each, a "Holder" and,
collectively and together with any permitted assigns, the "Holders").

                                   WITNESSETH:

         WHEREAS, the Company has agreed to grant certain registration rights to
the Holders with respect to an aggregate of 30,990 shares of Common Stock issued
by the Company to the Holders effective as of the date hereof pursuant to the
Asset Purchase Agreement dated October 9, 2000, between the Company and the
Holders (the "Purchase Agreement").

         NOW, THEREFORE, for valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, the parties hereto agree as follows:

         1.       Definitions.

                  "Additional Rights Holders" has the meaning set forth in
Section 2(a).

                  "Commission" means the Securities and Exchange Commission or
any other Federal agency at the time administering the Securities Act.

                  "Common Stock" means shares of the common stock, $.001 par
                  value per share, of the Company, and any capital stock of the
                  Company into which such Common Stock hereafter may be changed.

                  "Exchange Act" means the Securities Exchange Act of 1934, as
amended, and the rules and regulations of the Commission thereunder, all as the
same shall be in effect at the time. Reference to a particular section of the
Exchange Act shall include a reference to the comparable section, if any, of any
such similar Federal statute.

                  "Excluded Registration" means a registration statement on Form
S-4 or S-8 (or any successor form that may be adopted by the Commission) or a
registration statement filed in connection with an exchange offer or offering of
securities or debt solely to the Company's existing security or debt holders.



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                  "Filing Notice" has the meaning set forth in Section 2(a)
hereof.

                  "Holder" and "Holders" have the meanings set forth in the
first paragraph of this Agreement.

                  "Indemnified Party" means a party who is to be indemnified
pursuant to Section 6 hereof.

                  "Indemnifying Party" means a party who shall indemnify an
Indemnified Party pursuant to Section 6 hereunder.

                  "Inspectors" has the meaning set forth in Section 4(g) hereof.

                  "Material Adverse Effect" has the meaning set forth in Section
2(b) hereof.

                  "Piggy-back Registration" means the registration of a
Registrable Security pursuant to the terms and provisions of Section 2
hereunder, as defined in Section 2(a).

                  "Pro Rata Basis" means a pro rata allocation based on the
number of Registrable Securities requested to be included in a registered
offering pursuant to this Agreement.

                  "Records" has the meaning set forth in Section 4(g) hereof.

                  "Registrable Securities" means the shares of Common Stock
issued to the Holders pursuant to the Purchase Agreement, and any and all
securities of the Company issued with respect to such shares while they remain
Registrable Securities by way of a dividend, reclassification, stock split, or
other distribution or in connection with a combination of shares,
recapitalization, merger, consolidation or other reorganization or otherwise.
Any Registrable Security will cease to be a Registrable Security when (i) a
registration statement covering such Registrable Security has been declared
effective by the Commission and either the Registrable Security has been
disposed of pursuant to such effective registration statement or such
registration statement has remained effective for a period of 90 days, (ii) the
Registrable Security has been distributed or transferred (other than by one
Holder to the other), or (iii) the Registrable Security is eligible for sale
pursuant to Rule 144 (or any successor provision) under the Securities Act.

                  "Registration Expenses" means those expenses associated with
any registration statement filed hereunder, as described in Section 5.

                  "Securities Act" means the Securities Act of 1933, as amended,
or any similar Federal statute, and the rules and regulations of the Commission
thereunder, all as the same shall be in effect at the time. References to a
particular section of the Securities Act shall include a reference


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to the comparable section, if any, of any such similar or successor Federal
statute.

                  "Shelf Registration" has the meaning set forth in Section
2(a).

                  "Term" means that period of time as set forth in Section 9(a).

                  "Underwriter" means a securities dealer which purchases any
Registrable Securities as principal and not as part of such dealer's
market-making activities.

         2.       Piggy-back Registration.

                  (a) Request for Registration. At any time after the date
hereof until the first annual anniversary of the date hereof (the "Piggy-back
Term"), if (i) the Company proposes to file a registration statement under the
Securities Act (other than an Excluded Registration) with respect to an offering
of securities of the same class as the Registrable Securities by any of the
Company's security holders who previously have acquired shares of Common Stock
directly from the Company in exchange for a transfer of assets (excluding cash)
to the Company ("Additional Rights Holders") or (ii) any Additional Rights
Holder proposes to make an underwritten offering of such equity securities under
a previously filed registration statement pursuant to Rule 415 (or any successor
rule) under the Securities Act in which the Registrable Securities held by
Holders are included (a "Shelf Registration") and have not previously been
disposed of , then the Company shall give written notice (a "Filing Notice") of
such proposed filing or offering, as applicable, to each Holder who holds
Registrable Securities as soon as practicable (but in no event less than 20 days
before the anticipated effective date of the registration statement or the
commencement of the offering in the case of an offering made under a
registration statement pursuant to Rule 415 (or any successor rule) under the
Securities Act that previously has become effective). The Filing notice shall
offer each Holder the opportunity to (x) in the case of a registration under
clause (i) above, include all, but not less than all, of the Registrable
Securities held by such Holder in the registration statement proposed to be
filed or, at the Company's option, in a separate registration statement to be
filed concurrently with such registration statement or (y) in the case of an
underwritten offering to be made under a Shelf Registration that previously has
been declared effective, include in such offering all, but not less than all, of
such Holder's Registrable Securities covered by such registration statement that
have not previously been disposed of (a "Piggy-back Registration"), subject to
the limitations contained in Section 2(b) hereof. Within ten days after
receiving the Filing Notice, each Holder may make a written request to the
Company that all, but not less than all, of the Holder's Registrable Securities
be included in the Piggy-back Registration, which notice shall specify the
number of Registrable Securities to be so included. Subject to Section 2(b)
hereof, the Company shall include in the Piggy-back Registration (or, at the
Company's option, in a separate registration statement filed concurrently
therewith) all Registrable Securities with respect to which the Company has
received written requests for inclusion therein within ten days after the
receipt by each Holder of the Filing Notice. The Company may in its discretion
withdraw any registration statement filed pursuant to


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this Section 2(a) subsequent to its filing without liability to the Holders
except with respect to Registration Expenses. Any Holder shall be permitted to
withdraw all or part of such Holder's Registrable Securities requested to be
included in a Piggy-back Registration at any time prior to the effective date of
such Piggy-back Registration. Each Holder shall pay (or reimburse the Company)
for all registration or filing fees remitted by the Company to the Commission
with respect to the Registrable Securities of such Holder included in any
Piggy-back Registration.

                  (b) Priority on Piggy-back Registration. If any Piggy-back
Registration is to be an underwritten offering, the Company shall use its
commercially reasonable efforts to cause the managing Underwriter or
Underwriters to permit the shares of Registrable Securities requested by the
Holders to be included in the Piggy-back Registration (on the same terms and
conditions as securities of other security holders of the Company included
therein to the extent appropriate). Notwithstanding the foregoing, if the
managing Underwriter or Underwriters of such offering advise the Company in
writing that, in their opinion, the number of Registrable Securities and any
other securities requested to be included in such offering is sufficiently large
to materially and adversely affect the success of such offering (a "Material
Adverse Effect"), then (i) if such Piggy-back Registration is incident to a
secondary offering on behalf of Additional Rights Holders exercising demand
registration rights, the Company shall include in such registration statement
(A) first, the number of securities of such Additional Rights Holders on whose
behalf the Piggy-back Registration is being made (allocated among such persons
as they may so determine), (B) second, the number of Registrable Securities
requested to be included in such Piggy-back Registration pursuant to Section
2(a) and the number of shares of Common Stock requested to be included in such
Piggy-back Registration by all Additional Rights Holders in excess of the
securities included pursuant to clause (i)(A) that, in the good faith judgment
of such managing Underwriter or Underwriters, can be sold without causing a
Material Adverse Effect on such offering, allocated among each Holder and such
Additional Rights Holders whose securities are being included in the
registration pursuant to this clause (i)(B) (collectively with Holders, the
"Clause B Holders"), subject to any written agreement among such Clause B
Holders, on a Pro Rata Basis so that the total number of securities to be
included in the offering shall be the total number of securities recommended by
such managing Underwriter or Underwriters, unless any Clause B Holder desires to
include a number of Registrable Securities that is less than the total pro rata
amount that he is entitled to include, in which event the number of Registrable
Securities not so elected to be included shall be allocated among the other
Clause B Holders on a Pro Rata Basis, and (C) third, the number of securities
requested to be included in such Piggy-back Registration by the Company or by
other persons (other than Holders or Additional Rights Holders), allocated among
the Company and such persons as they may so determine or (ii) if such Piggy-back
Registration is incident to a secondary offering on behalf of Additional Rights
Holders, other than a Piggy-back Registration pursuant to clause (i) above, the
Company shall include in such Piggy-back Registration (X) first, the number of
securities requested to be included in such Piggy-back Registration pursuant to
Section 2(a) and by all Additional Rights Holders that, in the good faith
judgment of such managing Underwriter or Underwriters, can be sold without
causing a Material Adverse Effect on such offering, allocated among each Holder
and the


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Additional Rights Holders requesting securities to be included in such
Piggy-back Registration, subject to any written agreement among each Holder and
such Additional Rights Holder and any contractual priority granted to any
Additional Rights Holders, on a Pro Rata Basis in the same manner as provided in
class (i)(B) above and (Y) second, the number of securities requested to be
included in such Piggy-back Registration by the Company or by other persons
(other than Holders or Additional Rights Holders), allocated among the Company
and such persons as they may so determine.

                  (c) Exclusion for Underwritten Take-down. Any underwritten
takedown by any Additional Rights Holder under a Shelf Registration shall not
constitute a Piggy-back Registration for purpose of this Section 2 and Holders
shall not have any rights to participate in such underwritten takedown unless
(i) the Registrable Securities to be included in such takedown are included in
the Shelf Registration and (ii) Holders obtain the prior written consent of the
Company and the Additional Rights Holders effecting such takedown.

         3.       Holdback Agreement.

         (a) Unless the managing underwriter otherwise agrees, each Holder
agrees not to effect any public sale or private offer or distribution of any
shares of Common Stock or any other issue being registered or a similar security
of the Company, or any securities convertible into or exchangeable or
exercisable for such securities, during the 14 days prior to the anticipated
effectiveness under the Securities Act of any underwritten registration of any
such securities (or, with respect to an underwritten takedown of any such
securities under a shelf registration, prior to the pricing of such offering)
and during such time period (not to exceed 180 days) after the effectiveness
under the Securities Act of any underwritten registration (or, with respect to
an underwritten offering pursuant to a shelf registration statement, after the
pricing of such offering) as the Company and the managing underwriter may agree
(except as part of such underwritten registration or offering, as applicable).

         (b) To evidence the Holder's obligations under Section 3(a), each
Holder agrees to execute and deliver to the Company and the underwriters in an
underwriting offering to which Section 3(a) applies such lock-up agreements as
requested by the Company or the managing underwriter, in customary form and
substance reasonably acceptable to such Holder and consistent with Section 3(a).

         4.       Registration Procedures.

         Subject to the other provisions and limitations contained in this
Agreement, whenever any Holder has requested that Registrable Securities be
registered pursuant to Section 2 hereof, the Company will use its commercially
reasonable efforts to effect the registration and the sale of such Registrable
Securities in accordance with the intended method of disposition thereof, and in
connection with any such request, the Company will as expeditiously as
reasonably practicable:


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                  (a) prepare and file with the Commission a registration
statement on any form for which the Company then qualifies or which counsel for
the Company shall deem appropriate and which form shall be available for the
sale of the Registrable Securities to be registered thereunder in accordance
with the intended method of distribution thereof, and use its commercially
reasonable efforts to cause such filed registration statement to become
effective under the Securities Act;

                  (b) prepare and file with the Commission such amendments and
supplements to such registration statement and the prospectus used in connection
therewith as may be necessary to keep such registration statement effective for
such time period as the Company shall determine in its sole discretion (but not
before the expiration of the 90-day period referred to in subsection 4(3) of the
Securities Act and Rule 174 thereunder, if applicable);

                  (c) furnish to each Holder of Registrable Securities covered
by such registration statement, prior to filing the registration statement, if
requested, a copy of such registration statement as proposed to be filed, and
thereafter furnish to each such Holder such number of copies of such
registration statement, each amendment and supplement thereto (in each case
including all exhibits thereto and documents incorporated or deemed to be
incorporated therein by reference), the prospectus included in such registration
statement (including each preliminary prospectus), and such other documents as
each such Holder may reasonably request in order to facilitate the disposition
of the Registrable Securities owned by each such Holder;

                  (d) use its commercially reasonable efforts to register or
qualify such Registrable Securities under such other securities or blue sky laws
of such jurisdictions as each Holder of Registrable Securities covered by such
registration statement reasonably (in light of each such Holder's intended plan
of distribution) requests and do any and all other acts and things which may be
reasonably necessary to enable each Holder to consummate the disposition in such
jurisdictions of the Registrable Securities owned by each such Holder and keep
each such registration or qualification (or exemption therefrom) effective
during the period such registration statement is effective; provided, however,
that the Company will not be required to (i) qualify generally to do business in
any jurisdiction where it would not otherwise be required to qualify but for
this subsection, (ii) subject itself to taxation in any such jurisdiction, or
(iii) consent to general service of process in any such jurisdiction;

                  (e) at any time when a prospectus relating to Registrable
Securities is required to be delivered under the Securities Act, (i) notify each
Holder of Registrable Securities covered by the registration statement of the
occurrence of an event requiring the preparation of a supplement or amendment to
such prospectus, (ii) prepare and file such supplement, amendment or any other
required document so that, as thereafter delivered to the purchasers of such
Registrable Securities, such prospectus will not contain an untrue statement of
a material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein not misleading, and (iii) promptly
make available to each such Holder any such supplement, amendment or other
document;


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                  (f) enter into and perform customary agreements (including an
underwriting agreement in customary form with the managing Underwriter or
Underwriters, if any), use its commercially reasonable efforts to obtain any
necessary consents in connection with any proposed registration and sale of
Registrable Securities, and take such other actions as are reasonably required
in order to expedite or facilitate the disposition of such Registrable
Securities;

                  (g) make available for inspection during business hours on
reasonable advance notice by each Holder of Registrable Securities covered by
the registration statement, any Underwriter participating in any disposition
pursuant to such registration statement, and any attorney, accountant, or other
professional retained by any such Holder or such Underwriter (collectively, the
"Inspectors"), all financial and other records, pertinent corporate documents,
and properties of the Company (collectively, the "Records") as shall be
reasonably necessary to enable them to exercise their due diligence
responsibility, and cause the Company's officers, directors, and employees to
supply all information reasonably requested by any such Inspectors in connection
with such registration statement. Records which the Company determines, in good
faith, to be confidential and which it notifies the Inspectors are confidential
shall not be disclosed by the Inspectors unless (i) in the reasonable judgment
of counsel to the Company the disclosure of such Records is necessary to avoid
or correct a misstatement or omission in such registration statement or (ii) the
release of such Records is ordered pursuant to a subpoena or other order from a
court of competent jurisdiction. Each Holder agrees that information obtained by
him as a result of such inspections shall be deemed confidential and shall not
be used by him as the basis for any market transactions in the securities of the
Company unless and until such is made generally available to the public. Each
Holder further agrees that he will, upon learning that disclosure of such
Records is sought in a court of competent jurisdiction, give notice to the
Company and allow the Company, at the Company's expense, to undertake
appropriate action to prevent disclosure of the Records deemed confidential;

                  (h) if such sale is pursuant to an underwritten offering, use
its commercially reasonable efforts to obtain a comfort letter or comfort
letters from the Company's independent public accountants in customary form and
covering such matters of the type customarily covered by comfort letters as any
Holder of Registrable Securities covered by the registration statement or the
managing Underwriter or Underwriters may reasonably request;

                  (i) if requested by the managing Underwriter or Underwriters,
if any, or any Holder of Registrable Securities covered by the registration
statement in connection with an underwritten offering pursuant to Section 2
hereof, (i) promptly incorporate in a prospectus supplement or post-effective
amendment such information as the managing Underwriter or Underwriters, if any,
and/or any such Holder reasonable requests to be included therein, as may be
required by applicable laws and (ii) make all required filings of such
prospectus supplement or such post-effective amendment as soon as practicable
after the Company has received notification of the matters to be incorporated in
such prospectus supplement or post-effective amendment; provided, however, that
the Company shall not be required to take any actions pursuant to this Section
4(i) that


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are not, in the reasonable opinion of counsel for the Company, in compliance
with applicable law;

                  (j) use its commercially reasonable efforts to obtain the
withdrawal of any order suspending the effectiveness of a registration statement
filed in connection herewith, or the lifting of any suspension of the
qualification (or exemption from qualification) of any of the Registrable
Securities for sale in any jurisdiction, at the earliest possible moment;

                  (k) cooperate with each Holder of Registrable Securities
covered by the registration statement and the managing Underwriters, if any, to
facilitate the timely preparation and delivery of certificates representing
Registrable Securities to be sold, which certificates or notes shall not bear
any restrictive legends and shall be in a form eligible for deposit with the
transfer agent for the Common Stock; and enable such Registrable Securities to
be in such denominations and registered in such names as the managing
Underwriters, if any, or holders may request at least two business days prior to
any sale of Registrable Securities; and

                  (l) take such other actions as are reasonably required in
order to expedite or facilitate the disposition of such Registrable Securities.

         The Company may require each Holder to promptly furnish in writing to
the Company such information regarding the distribution of the Registrable
Securities as the Company may from time to time reasonably request and such
other information as may be legally required in connection with such
registration.

         Each Holder shall cooperate with the Company and, if applicable, the
Underwriter or Underwriters in providing such information and executing and
delivering such documents as the Company or the Underwriter or Underwriters
reasonably shall request in connection with any registration of Registrable
Securities pursuant to this Agreement, and the Company shall not be obligated to
include in any such registration any Registrable Securities of any Holder who
does not comply with this paragraph.


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         Each Holder of Registrable Securities covered by a Piggy-back
registration agrees that, upon receipt of any notice from the Company of the
happening of any event of the kind described in Section 4(e) hereof (which
notice and any information regarding such event are acknowledged to constitute
material non-public information regarding the Company and which shall be kept
confidential and shall not be disclosed by the Holders), such Holder will
forthwith discontinue disposition of Registrable Securities pursuant to the
registration statement covering such Registrable Securities until such Holder's
receipt of the copies of the supplemented or amended prospectus contemplated by
Section 4(e) hereof, and, if so directed by the Company, such Holder will
deliver to the Company all copies, other than permanent file copies then in such
Holder's possession, of the most recent prospectus covering such Registrable
Securities at the time of receipt of such notice.

         Notwithstanding any provision of this Agreement, the Company shall not
be required to maintain the effectiveness of any registration statement in which
Registrable Securities are included after such time as all Registrable
Securities included therein shall cease to be Registrable Securities.

         5. Registration Expenses. In connection with any registration statement
in which Registrable Securities are included as permitted in Section 2, the
Company shall pay the following registration expenses (the "Registration
Expenses"): (i) fees and expenses of compliance with securities or blue sky laws
(including reasonable fees and disbursements of counsel in connection with blue
sky qualifications of the Registrable Securities); (ii) printing expenses
(including expenses of printing certificates for Registrable Securities); (iii)
internal expenses (including, without limitation, all salaries and expenses of
its officers and employees performing legal or accounting duties); (iv) any fees
and expenses incurred in connection with the listing of the Registrable
Securities on the national securities exchange or automated quotation system on
which the Common Stock is listed; (v) reasonable fees and disbursements of
counsel for the Company and customary fees and expenses for independent
certified public accountants retained by the Company (including the costs
associated with the delivery by independent certified public accountants of a
comfort letter or comfort letters requested pursuant to Section 4(h) hereof);
(vi) the reasonable fees and expenses of any special experts or other persons
retained by the Company in connection with such registration; and (vii)
messenger, delivery and telephone expenses of the Company related to any
registration contemplated hereunder. The Company shall not have any obligation
to pay any underwriting fees, discounts, or commissions attributable to the sale
of Registrable Securities, or any out-of-pocket expenses of any Holder (or the
agents who manage his accounts), which amounts shall be the responsibility of
the selling Holder or Holders. In connection with any Piggy-back Registration,
each Holder who has Registrable Securities included in such Piggy-back
Registration shall pay all registration and filing fees relating to the
Registrable Securities of such Holder included in such registration.


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         6.       Indemnification; Contribution.

                  (m) Indemnification by the Company. The Company agrees to
indemnify and hold harmless each Holder of Registrable Securities and, if
applicable, its directors and officers and each person who controls such Holder
within the meaning of either section 15 of the Securities Act or section 20 of
the Exchange Act, covered by a Piggy-back Registration from and against any and
all losses, claims, damages, liabilities and expenses (including reasonable
legal and other costs of investigation and defense) (collectively, "Losses")
arising out of or based upon any untrue statement or alleged untrue statement of
a material fact contained in any such registration statement or prospectus
relating to the Registrable Securities or in any amendment or supplement thereto
or in any preliminary prospectus, or arising out of or based upon 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, except
insofar as such Losses arise out of, or are based upon, any such untrue
statement or omission or allegation thereof based upon information furnished in
writing to the Company by such Holder or on such Holder's behalf expressly for
use therein; provided, however, that with respect to any untrue statement or
omission or alleged untrue statement or omission made in any preliminary or
final prospectus, the indemnity agreement contained in this subsection shall not
apply to the extent that any such Losses result from the fact that a current
copy of the prospectus was not sent or given to the person asserting any such
Losses at or prior to the written confirmation of the sale of the Registrable
Securities concerned to such person if it is determined that it was the
responsibility of such Holder to provide such person with a current copy of the
prospectus and such current copy of the prospectus would have cured the defect
giving rise to such Losses. The Company also agrees to indemnify any
Underwriters of the Registrable Securities, their officers and directors, and
each person who controls such Underwriters within the meaning of either section
15 of the Securities Act or section 20 of the Exchange Act on substantially the
same basis as the indemnification of Holders provided in this subsection 6(a).

                  (n) Indemnification by Holders. Each Holder, jointly and
severally, agrees to indemnify and hold harmless the Company, its directors and
officers, and each person, if any, who controls the Company within the meaning
of either section 15 of the Securities Act or section 20 of the Exchange Act
(other than the Holder), covered by a Piggy-back Registration from and against
any and all Losses arising out of or based upon any untrue statement or alleged
untrue statement of a material fact contained in any such registration statement
or prospectus relating to the Registrable Securities or in any amendment or
supplement thereto or in any preliminary prospectus, or arising out of or based
upon 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,
but only insofar as such Losses arise out of, or are based upon, any such untrue
statement or omission or allegation thereof based upon information furnished in
writing to the Company by such Holder or on such Holder's behalf, expressly for
use therein; provided, however, that with respect to any untrue statement or
omission or alleged untrue statement or omission made in any preliminary or
final prospectus, the indemnity agreement contained in this subsection shall not
apply to the extent that any such Losses result from the fact that a current
copy of the prospectus was not sent or given to the person asserting


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any such Losses at or prior to the written confirmation of the sale of the
Common Stock concerned to such person if it is determined that it was the
responsibility of the Company or any other person or entity (other than the
Holder) to provide such person with a current copy of the prospectus and such
current copy of the prospectus would have cured the defect giving rise to such
Losses. Each Holder also agrees, jointly and severally, to indemnify and hold
harmless underwriters of the Registrable Securities, their officers and
directors, and each person who controls such underwriters within the meaning of
either section 15 of the Securities Act or section 20 of the Exchange Act on
substantially the same basis as the indemnification of the Company provided in
this subsection 7(b).

                  (o) Conduct of Indemnification Proceedings. If any action or
proceeding (including any governmental investigation) shall be brought or
asserted against any person entitled to indemnification under subsections (a) or
(b) above (an "Indemnified Party") in respect of which indemnity may be sought
from any party who has agreed to provide such indemnification (an "Indemnifying
Party"), the Indemnified Party shall promptly notify the Indemnifying Party in
writing, and the Indemnifying Party shall assume the defense thereof, including
the employment of counsel reasonably satisfactory to such Indemnified Party, and
shall assume the payment of all expenses. The Indemnified Party shall have the
right to employ separate counsel in any such action and to participate in the
defense thereof, but the fees and expenses of such counsel shall be at the
expense of such Indemnified Party unless (i) the Indemnifying Party has agreed
to pay such fees and expenses, (ii) the Indemnifying Party shall have failed to
promptly assume the defense of such action or proceeding and to employ counsel
reasonably satisfactory to the Indemnified Party, (iii) the named parties to any
such action or proceeding (including any impleaded parties) include both such
Indemnified Party and the Indemnifying Party, and such Indemnified Party shall
have been advised by counsel that there is a conflict of interest on the part of
counsel employed by the Indemnifying Party to represent such Indemnified Party,
or (iv) the Indemnified Party's counsel shall have advised the Indemnified Party
that there may be defenses available to the Indemnified Party that are different
from or in addition to those available to the Indemnifying Party and that the
Indemnifying Party is not able to assert on behalf of or in the name of the
Indemnified Party (in which case of either (iii) or (iv), if such Indemnified
Party notifies the Indemnifying Party in writing that it elects to employ
separate counsel at the expense of the Indemnifying Party, the Indemnifying
Party shall not have the right to assume the defense of such action or
proceeding on behalf of such Indemnified Party); it being understood, however,
that the Indemnifying Party shall not, in connection with any one such action or
proceeding or separate but substantially similar or related actions or
proceedings in the same jurisdiction arising out of the same general allegations
or circumstances, be liable for the fees and expenses of more than one separate
firm of attorneys (together with appropriate local counsel) at any time for all
such Indemnified Parties, which firm shall be designated in writing by such
Indemnified Parties. The Indemnifying Party shall not be liable for any
settlement of any such action or proceeding effected without its written
consent, which consent shall not be unreasonably withheld, but if settled with
its written consent, or if there be a final judgment for the plaintiff in any
such action or proceeding, the Indemnifying Party shall indemnify and hold
harmless such Indemnified Parties from and against any loss or liability (to the
extent stated above) by reason of such settlement or judgment.


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<PAGE>
                  (p) Contribution. If the indemnification provided for in this
Section 6 is unavailable to the Indemnified Parties in respect of any Losses
(other than by reason of exceptions provided in subsection 6(a) or 6(b)), then
each Indemnifying Party, in lieu of indemnifying such Indemnified Party, shall
contribute to the amount paid or payable by such Indemnified Party as a result
of such Losses (i) in such proportion as is appropriate to reflect the relative
fault of the Company, on the one hand, and Holders (together with any other
selling stockholder that may be obligated thereon pursuant to similar
indemnification or contribution provisions as contained herein), on the other
hand, with respect to the statements or omissions which resulted in such Losses,
or action in respect thereof, as well as any other relevant equitable
considerations or (ii) if the allocation provided by clause (i) above is not
permitted by applicable law, in such proportion as shall be appropriate to
reflect the relative benefits received by the Company, on the one hand, and
Holders (together with any other selling stockholder that may be obligated
thereon pursuant to similar indemnification or contribution provisions as
contained herein), on the other hand, from the offering of the securities
covered by such registration statement. The relative fault of the Company on the
one hand and of Holders (together with any other selling stockholder that may be
obligated thereon pursuant to similar indemnification or contribution provisions
as contained herein) on the other shall be determined by reference to, among
other things, whether the untrue or alleged untrue statement of a material fact
or the omission or alleged omission to state a material fact relates to
information supplied by such party, and such party's relative intent, knowledge,
access to information, and opportunity to correct or prevent such statement or
omission. The relative benefits received by the Company on the one hand and
Holders (together with any other selling stockholder that may be obligated
thereon pursuant to similar indemnification or contribution provisions as
contained herein) on the other shall be deemed to be in the same proportion as
the total proceeds from the offering (net of underwriting discounts and
commissions but before deducting expenses) received by the Company bears to the
total proceeds (net of underwriting discounts and commissions but before
deducting expenses) received by the Holders (together with any other selling
stockholder that may be obligated thereon pursuant to similar indemnification or
contribution provisions as contained herein).

         The Company and each Holder agree that it would not be just and
equitable if contribution pursuant to this subsection 6(d) were determined by
pro rata allocation (even if the Underwriters were treated as one entity for
such purpose) or by any other method of allocation which does not take into
account the equitable considerations referred to in the immediately preceding
subsection. Notwithstanding the provisions of this subsection 6(d), no Holder
shall be required to contribute any amount in excess of the amount by which the
total price at which the securities of such Holder were offered to the public
exceeds the amount of any damages which such Holder has otherwise been required
to pay by reason of such untrue or alleged untrue statement or omission or
alleged omission. No person guilty of fraudulent misrepresentation (within the
meaning of subsection 11(f) of the Securities Act) shall be entitled to
contribution from any person who was not guilty of such fraudulent
misrepresentation.


REGISTRATION RIGHTS AGREEMENT                                     Page 12 of 16

<PAGE>

                  (q) Survival. The indemnity and contribution agreements
contained in this Section 6 shall remain operative and in full force and effect
regardless of (i) any termination of this Agreement or any underwriting
agreement, (ii) any investigation made by or on behalf of any Indemnified Party
or by or on behalf of the Company, and (iii) the consummation of the sale or
successive resale of the Registrable Securities.

         7. Participation in Underwritten Registrations. No Holder may
participate in any underwritten registration hereunder unless such Holder (i)
agrees to sell his securities on the basis provided in any underwriting
arrangements approved by the persons or entities entitled hereunder to approve
such arrangements and (ii) completes and executes all questionnaires, powers of
attorney, indemnities, underwriting agreements, and other documents reasonably
required under the terms of such underwriting arrangements and this Agreement;
provided, however, that no such Holder shall be required to make any
representations or warranties in connection with any such registration other
than representations and warranties as to (x) such Holder's ownership of his or
its Registrable Securities to be sold or transferred free and clear of all
liens, claims, and encumbrances, (y) such Holder's power and authority to effect
such transfer, and (z) such matters pertaining to compliance with securities
laws as may be reasonably requested; provided further, however, that the
liability of the Holders to indemnify pursuant to any such underwriting
arrangements will be in proportion to, and will be limited to, the net amount
received by the Holders from the sale of Registrable Securities pursuant to such
registration.

         8. Company Purchase Option. Notwithstanding the terms of this
Agreement, if at any time that any Holder requests any Registrable Securities to
be included in a registration statement pursuant to this Agreement securities of
the same class or series as the Registrable Securities are traded on a national
securities exchange or authorized to be quoted on the NASDAQ or any other
recognized quotation system which regularly provides quotes on such securities
(a "Trading Forum"), the Company shall have the right and option, in its sole
discretion, to, in lieu of including such Registrable Securities in such
registration statement, purchase all or any portion of such Registrable
Securities requested to be included in such registration statement at the
closing or last sales price of such security reported by such Trading Forum on
the date the Demand Notice or written notice requesting the inclusion of such
Registrable Securities in such registration statement is received by the Company
or, if there is no such reported quote for such date by any Trading Forum, the
last reported closing or sales price, as applicable, of such security by a
Trading Forum.

         9.       Miscellaneous.

                  (r) Term. This Agreement shall terminate on the earlier to
occur of (i) the first anniversary of the date hereof or (ii) the first date on
which there are no longer any Registrable Securities (the "Term").

                  (s) Amendments and Waivers. The provisions of this Agreement
may not be amended, modified, or supplemented, and waivers or consents to
departures from the provisions


REGISTRATION RIGHTS AGREEMENT                                     Page 13 of 16

<PAGE>

hereof may not be given, unless the Company has obtained the written consent of
the Holders holding a majority of the Registrable Securities.

                  (t) Notices. All notices and other communications provided for
or permitted hereunder shall be made in writing by hand delivery, registered
first-class mail, telex, telecopier, or air courier guaranteeing overnight
delivery:

                           (i) if to Holders, at the most current address given
         to the Company in accordance with the provisions of this subsection,
         which address initially is:


                                            Blake ___. Twedt
                                            10224 Oasis Palm Drive
                                            Tampa, Florida  33615
                                            Attention: ________________________
                                            Telecopier: (813) 249-2381

                                            John ___. Dudek
                                            11672 Harborside Circle
                                            Largo, Florida  33773
                                            Attention: ________________________
                                            Telecopier: (240) 220-7284

                           (ii) if to the Company, at its most current address
         and thereafter at such other address as may be designated from time to
         time by notice given in accordance with the provisions of this section,
         which address initially is:

                                            Nucentrix Broadband Networks, inc.
                                            4120 International Parkway
                                            Suite 2000
                                            Carrollton, Texas 75007-1906
                                            Attention: J. Curtis Henderson
                                            Telecopier: (972) 662-3800

                  (u) Successors and Assigns. The Company and the Holders shall
not assign their respective rights or obligations hereunder without the prior
written consent of the Holders or the Company, respectively.

                  (v) Counterparts. This Agreement may be executed in a number
of identical counterparts and it shall not be necessary for the Company and each
Holder to execute each of such counterparts, but when both have executed and
delivered one or more of such counterparts, the several parts, when taken
together, shall be deemed to constitute one and the same instrument,


REGISTRATION RIGHTS AGREEMENT                                     Page 14 of 16

<PAGE>

enforceable against each in accordance with its terms. In making proof of this
Agreement, it shall not be necessary to produce or account for more than one
such counterpart executed by the party against whom enforcement of this
Agreement is sought.

                  (w) Headings. The headings in this Agreement are for
convenience of reference only and shall not limit or otherwise affect the
meaning hereof.

                  (x) Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS, WITHOUT REGARD TO
PRINCIPLES OF CONFLICTS OR CHOICE OF LAW.

                  (y) Severability. If any provision of this Agreement is held
to be illegal, invalid, or unenforceable under present or future laws effective
during the term of this Agreement, such provision shall be fully severable; this
Agreement shall be construed and enforced as if such illegal, invalid, or
unenforceable provision had never comprised a part of this Agreement; and the
remaining provisions of this Agreement shall remain in full force and effect and
shall not be affected by the illegal, invalid, or unenforceable provision or by
its severance from this Agreement. Furthermore, in lieu of each such illegal,
invalid, or unenforceable provision, there shall be added automatically as a
part of this Agreement a provision as similar in terms to such illegal, invalid,
or unenforceable provision as may be possible and be legal, valid, and
enforceable.

                  (z) Additional Agreements. The Company shall have the right at
any time to enter into any agreement with respect to its securities which grant
registration or similar rights to third parties that are senior to or provide
priority over the Registrable Securities in connection with any registration
under the Securities Act of securities of the Company.

                  (aa) Entire Agreement. This Agreement is intended by the
Company and the Holders as a final expression of their agreement and is intended
to be a complete and exclusive statement of their agreement and understanding in
respect of the subject matter contained herein. This agreement supersedes all
prior agreements and understandings between the Company and the Holders with
respect to such subject matter.

                  (bb) Third Party Beneficiaries. This Agreement is intended for
the benefit of the Company and the Holders and their respective successors and
assigns and is not for the benefit of, nor may any provision hereof be enforced
by, any other person or entity.


REGISTRATION RIGHTS AGREEMENT                                     Page 15 of 16

<PAGE>

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date first above written.

                                         NUCENTRIX BROADBAND NETWORKS, INC.



                                         By:    /s/ J. Curtis Henderson
                                                -------------------------------
                                         Name:  J. Curtis Henderson
                                         Title: Sr. Vice President, General
                                                  Counsel and Secretary



                                                /s/ Blake Twedt
                                                -------------------------------
                                                Blake Twedt


                                                /s/ John Dudeck
                                                -------------------------------
                                                John Dudeck


REGISTRATION RIGHTS AGREEMENT                                     Page 16 of 16