EXHIBIT 10.42

                         MORTGAGE AND SECURITY AGREEMENT

          (Property Address: 38 Jordan Road, Brookline, Massachusetts)

      This Mortgage and Security Agreement ("this Mortgage") is granted this 3rd
day of April, 2001 by LINDA J. ISAACSON AND MARK S. ISAACSON, AS TRUSTEES UNDER
THE RASHI REALTY TRUST DATED FEBRUARY 22, 1991 with a notification address at 38
Jordan Road, Brookline, Massachusetts ("Mortgagor"), to AMBIENT CORPORATION, a
Delaware corporation with a principal place of business located at 1033 Beacon
Street, Brookline, MA 02446-5654 ("Mortgagee").

A. Grant of Mortgage

      For consideration paid, Mortgagor grants the Mortgaged Premises to
Mortgagee, with MORTGAGE COVENANTS, to secure the payment and performance of:

      1. The payment of One Million Nine Hundred and Ninety Thousand Dollars and
00/100 ($1,990,000) with no interest thereon, with the principal due and payable
in one installment on the date which is ten (10) years from the date first set
forth above, together with any charges thereon, as set forth in and evidenced by
a certain promissory note of Mortgagor to Mortgagee of even date herewith, which
note is in the sum of One Million Nine Hundred and Ninety Thousand Dollars and
00/100 ($1,990,000) (the "Note"), or in any extensions, renewals, replacements
and modifications thereof;

      2. The payment and performance of all agreements and obligations set forth
in the Note and/or in this Mortgage; and

      3. The payment, performance and discharge of each and every covenant and
agreement and all other debts, loans, liabilities, and other obligations of
Mortgagor to Mortgagee now existing or hereafter arising, direct or indirect,
absolute or contingent.

      4. Notwithstanding the foregoing, it is specifically understood and agreed
that the obligations of Linda J. Isaacson hereunder shall be limited to the
extent of her interest in the Mortgaged Premises (as defined below). Nothing
herein shall be construed as applying to any party other than Linda L. Isaacson.

(collectively referred to as the "Obligations").

B. Mortgaged Premises.

      The term "Mortgaged Premises" shall mean and include all of the following
described property:
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      1. The land together with the improvements and other structures now or
hereafter situated thereon located in Brookline, Massachusetts, which land is
more particularly described on Exhibit "A" which is annexed hereto and made a
part hereof, together with all rights, privileges, tenements, hereditaments,
appurtenances and easements, including, but not limited to, rights and easements
for access and egress and utility connections, and other rights now or hereafter
appurtenant thereto (the "Real Estate");

      2. All real estate fixtures or items which by agreement of the parties may
be deemed to be such fixtures, now or hereafter owned by Mortgagor, or in which
Mortgagor has an interest, and now or hereafter located in or upon the Real
Estate, or now or hereafter attached to, installed in, or used in connection
with any of the Real Estate, including, but not limited to, any and all
bathroom, plumbing, heating, lighting, refrigerating, ventilating and
air-conditioning apparatus and equipment, doorbell and alarm systems, window
shades, screens, awnings, screen doors, storm and other detachable windows and
doors, mantels, partitions, built-in cases, counters and other fixtures whether
or not included in the foregoing enumeration (the "Fixtures");

      3. All bridges, easements, rights of way, licenses, privileges,
hereditaments, permits and appurtenances hereafter belonging to or enuring to
the benefit of the Real Estate and all right, title and interest of Mortgagor in
and to the land lying within any street or roadway adjoining the Real Estate and
all right, title and interest of Mortgagor in and to any vacated or hereafter
vacated streets or roads adjoining the Real Estate and any and all reversionary
or remainder rights (the "Additional Appurtenances");

      4. All of the right, title and interest of Mortgagor in and to any award
or awards heretofore made or hereafter to be made by any municipal, county,
state or federal authorities to the present or any subsequent owners of the Real
Estate, or the Fixtures, or the Additional Appurtenances, or the Leases or the
Personal Property (as those terms are defined below), including, without
limitation, any award or awards, or settlements or payments, hereafter made
resulting from (x) condemnation proceedings or the taking of the Real Estate, or
the Fixtures, or the Additional Appurtenances, or the Leases or the Personal
Property, or any part thereof, under the power of eminent domain, or (y) the
alteration of grade or the location or discontinuance of any street adjoining
the Real Estate or any portion thereof, or (z) any other injury to or decrease
in value of the Mortgaged Premises, and Mortgagor hereby agrees to execute and
deliver from time to time such further instruments as may be requested by
Mortgagee to confirm such assignment to Mortgagee of any such award, damage,
payment or other compensation (the "Awards");

      5. All leases now or hereafter entered into of the Real Estate, or any
portion thereof, and all rents, issues, profits, revenues, earnings and
royalties therefrom, and all right, title and interest of Mortgagor thereunder,
including, without limitation, cash, letters of credit, or securities deposited
thereunder to secure performance by the tenants or occupants of their
obligations thereunder, whether such cash, letters of credit, or securities are
to be held until the expiration of the terms of such leases or occupancy
agreements or applied to one or more of the installments of rent coming due
prior to the expiration of such terms including, without limitation, the right
to receive and collect the rents thereunder (the "Leases");


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      6. All purchase and sale agreements now or hereafter entered into of the
Real Estate, or any portion thereof, including, without limitation, cash,
letters of credit or securities deposited thereunder to secure performance by
the purchasers of their obligations thereunder (the "Purchase and Sale
Agreements"); and

      7. All tangible and intangible personal property now owned or at any time
hereafter acquired by Mortgagor of every nature and description, and used in any
way in connection with the Real Estate, the Fixtures, the Additional
Appurtenances, the Purchase and Sale Agreements or any other portion of the
Mortgaged Premises, including, without limitation express or implied upon the
generality of the foregoing, all: goods; materials; supplies; equipment;
furnishings; fixtures; accounts; chattel paper; documents; instruments; money;
bank accounts; security deposits; claims to rebates, refunds or abatements of
real estate taxes or any other taxes; contract rights; plans and specifications;
permits, licenses, approvals and other rights; general intangibles; the rights
of Mortgagor under contracts with respect to the Real Estate or any other
portion of the Mortgaged Premises; all proceeds paid for any damage or loss to
all or any portion of the Real Estate, the Fixtures, the Additional
Appurtenances or any other portion of the Mortgaged Premises; all Awards; all
Leases; all Purchase and Sale Agreements; and all proceeds, products, additions,
accessions, substitutions and replacements to any one or more of the foregoing
(collectively, the "Personal Property").

C. Grant of Security Interest.

      This instrument shall also constitute a security agreement under Article 9
of the Massachusetts Uniform Commercial Code, as amended (the "Uniform
Commercial Code"). To secure the Obligations, Mortgagor hereby grants to
Mortgagee a security interest in all Awards, Personal Property, Purchase and
Sale Agreements, and Fixtures of every kind and description now or hereafter
owned by Mortgagor or in which Mortgagor has an interet (but only to the extent
of such interest), situated or to be situated upon or used in connection with
the Real Estate, together with any renewals, replacements, or additions thereto
or substitutions therefor, as well as all proceeds thereof, whether now or
hereafter existing.

      Mortgagee shall have all of the rights and remedies, in addition to those
specified herein, of a secured party under the Uniform Commercial Code, as
amended. Except for the security interest granted hereby, Mortgagor is, and as
to any Personal Property acquired hereafter will be, the sole owner of the
Personal Property, free from any adverse lien, security interest, encumbrance or
adverse claims thereon of any kind whatsoever. Mortgagor shall notify Mortgagee
of, and will defend the Personal Property against, all claims and demands of all
persons at any time claiming the same or any interest therein. All covenants and
Obligations of Mortgagor contained in this Mortgage shall be deemed to apply to
the Personal Property, whether or not expressly referred to herein.


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D. Covenants.

      Mortgagor covenants and agrees with Mortgagee, its successors and assigns,
that:

      1. Performance of Obligations. Except for the limitation applicable to
Linda J. Isaacson as set forth in Section A(4) above, Mortgagor and each
endorser or guarantor of the Note will pay the principal of the Note and charges
thereon as the same shall become due and payable and will pay and perform all of
the other Obligations.

      2. Title. Mortgagor is the owner of the Mortgaged Premises and has good
right, full power and lawful authority to grant this Mortgage. The Mortgaged
Premises are free and clear of all encumbrances except those enumerated on the
policy of title insurance delivered by Mortgagor to Mortgagee. Also, there are
no leases outstanding for all or any portion of the Mortgaged Premises.
Mortgagor will make any further assurances of title that Mortgagee may require.
Mortgagor shall notify Mortgagee of, and will defend the Mortgaged Premises
against, all claims and demands of all persons at any time claiming the same or
any interest therein. Mortgagor agrees to execute and deliver on demand such
other mortgages and other instruments as Mortgagee may reasonably request in
order to perfect its mortgage upon any of the Mortgaged Premises. Mortgagor will
perform and observe and not violate nor suffer the violation of any covenants,
restrictions or other agreements of record against the Mortgaged Premises.

      3. Protection and Maintenance. Mortgagor will protect and maintain or
cause to be protected and maintained in first class order, repair and condition
at all times (damage by casualty expressly not excepted), the buildings and
other structures now standing or hereafter erected on the Mortgaged Premises,
and any additions and improvements thereto, and the utility services, driveways
and all fixtures, equipment, and articles of Personal Property now or hereafter
acquired and used in connection with the operation of the Real Estate, promptly
replacing any of the aforesaid which may become lost, destroyed or unsuitable
for use with other property of similar character and quality.

      4. No Waste; Compliance with Law. Mortgagor will not commit or suffer any
demolition, removal or material alteration of any of the Mortgaged Premises
without Mortgagee's prior written consent, or commit or suffer any strip or
waste, or demolition, removal or material alteration, of the Mortgaged Premises
or any violation of law, rule, regulation, ordinance, license or permit, or the
requirements of any licensing or insuring authority, and will keep in full force
and effect all licenses, permits and other governmental approvals affecting the
Mortgaged Premises.

      5. Insurance Coverage. Mortgagor will keep the buildings, improvements,
Fixtures and Personal Property on the Mortgaged Premises insured with so-called
"all risk" or "special form" casualty insurance policies, and such other forms
of coverage as Mortgagee shall require, in an amount which, in Mortgagee's
judgment, shall be 100% of the full insurable value of said buildings,
improvements, Fixtures and Personal Property and not less than an amount
sufficient to prevent Mortgagor from becoming a co-insurer within the terms of
such policies. Mortgagor shall also provide, maintain and keep in full force and
effect public liability insurance with limits acceptable to Mortgagee. Mortgagor
shall also provide, maintain, and keep in force, if the buildings and
improvements (or any part thereof) are located in a flood prone, flood risk or
flood hazard area as designated pursuant to the Federal Flood Disaster
Protection Act of 1973, as amended, and regulations thereunder, a policy of
flood insurance issued under and in compliance with that Act and those
regulations in an amount determined from time to time by Mortgagee and which
will comply with the requirements of that Act and those regulations.


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      All insurance policies shall be subject to Mortgagee's review and
approval, shall be written by insurers authorized to conduct business in the
state in which the Mortgaged Premises are located and otherwise acceptable to
Mortgagee, and shall be first payable in case of loss to Mortgagee under the
standard New England mortgagee clause, so-called, or its equivalent; provided,
that the Personal Property insurance policies shall designate Mortgagee as an
additional insured and shall contain a Lender's Loss Payee endorsement. The
original of all such policies of insurance (or certificates thereof issued by
the insurer in form, content and manner of execution satisfactory to Mortgagee)
shall be delivered to Mortgagee, and Mortgagor shall deliver to Mortgagee a new
policy (or such a certificate) as replacement for an expiring policy (or such a
certificate) required to be deposited hereunder at least thirty (30) days before
the date of such expiration. Mortgagor hereby irrevocably appoints Mortgagee its
true and lawful attorney-in-fact, with full power of substitution, in the event
of default, to deal with the insurer with respect to all matters arising under
the policy and in the event of foreclosure of this Mortgage to assign any
policy.

      6. Insurance Proceeds. The proceeds of any hazard insurance shall, at the
discretion of Mortgagee, be applied to or toward the indebtedness or other
Obligations secured hereby in such order as Mortgagee may determine. If
Mortgagee shall require repair of that part of the Mortgaged Premises so damaged
by such insured hazard, Mortgagee shall release to Mortgagor insurance proceeds
paid to it upon such conditions as Mortgagee may prescribe and Mortgagor shall
apply all of such proceeds to the repair and restoration of the Mortgaged
Premises.

      7. Eminent Domain. The awards of damages on account of any condemnation
for public use of or injury to the Mortgaged Premises shall be paid to
Mortgagee. Such awards shall, at the discretion of Mortgagee, be applied to or
toward the Obligations secured hereby in such order as Mortgagee may determine,
or shall be released to Mortgagor upon such conditions as Mortgagee in its sole
judgment may prescribe to be applied to restoration of that part of the
Mortgaged Premises which remains, but not more than such portion of such awards
as may be required to repair such damage or injury and restore the Mortgaged
Premises to its former condition shall be so applied. Any balance remaining
shall be applied by Mortgagee to or toward the indebtedness and other
Obligations secured hereby in such order as Mortgagee in its discretion shall
determine.


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      8. Due on Sale; No Other Encumbrances; No Transfer of Ownership Interests.
It shall be a breach of the condition of this Mortgage and an event permitting
Mortgagee to accelerate all indebtedness secured hereby, if, without Mortgagee's
prior written consent in each instance, which consent may be granted, withheld
or conditionally granted in Mortgagee's sole discretion: (a) there is any sale,
conveyance, transfer or encumbrance of all or any portion of the Mortgaged
Premises; or (b) there is any transfer, or assignment of, or grant of any
security interest in, any of the ownership interests in Mortgagor; or (c) there
is a failure to comply with the provisions of, or there is a default under, any
exceptions to title set forth in the title insurance policy delivered to
Mortgagee unless cured within applicable grace periods provided for in the title
exceptions.

      9. Mortgagee's Rights to Deal with Mortgagor's Successors. Mortgagee,
without notice to any person, may deal with any successor in interest of
Mortgagor herein regarding this Mortgage and the debt and other Obligations
hereby secured in all respects as it might deal with Mortgagor herein, without
in any way affecting the liability hereunder, or on the debt or other
Obligations secured hereby, of any predecessor in interest of the person so
dealt with. No sale of all or any part of the Mortgaged Premises, nor any
forbearance on the part of Mortgagee, nor any extension by Mortgagee of the time
for payment and performance of the debt and other Obligations hereby secured,
shall operate to release, discharge, modify, change or affect the original
liability of any predecessor in interest to the equity owner at the time of such
sale, forbearance or extension.

      10. Payment of Taxes. Mortgagor will pay before delinquent or before any
penalty for nonpayment attaches thereto, all taxes, assessments and charges of
every nature and to whomever assessed that may now or hereafter be levied or
assessed upon the Mortgaged Premises or any part thereof, or upon the rents,
issues, income or profits thereof or upon the lien or estate hereby created,
whether any or all of said taxes, assessments or charges be levied directly or
indirectly or as excise taxes or as income taxes.

      11. No Other Liens. Mortgagor will pay all sums which, if unpaid, may
result in the acquisition of a lien of superior or inferior priority to this
Mortgage and the lien created hereby before such lien may attach or which may
result in conferring upon a tenant of any part or all of the Mortgaged Premises
a right to recover such sums as prepaid rent.

      12. Hazardous Materials and Oil.

      A. Mortgagor shall indemnify, defend and hold Mortgagee harmless from and
against any claim brought or threatened against Mortgagee by Mortgagor, any
guarantor or endorser of the Obligations, or by any governmental agency or
authority or any other person (as well as from reasonable attorneys' fees and
expenses in connection therewith) on account of the presence of Hazardous
Material or oil on the Mortgaged Premises or other property of Mortgagor held as
collateral by Mortgagee, or the failure by Mortgagor to comply with the terms
and provisions of any Hazardous Waste Law (each of which claims may be defended,
compromised, settled or pursued by Mortgagee with counsel of Mortgagee's
selection but at the expense of Mortgagor). This indemnification shall survive
payment of the Obligations and/or any termination, release or discharge executed
by Mortgagee in favor of Mortgagor.


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<PAGE>

      B. As used herein:

            (i)   The term "Hazardous Materials" shall mean and include
                  asbestos, polychlorinated biphenyls ("PCB's"), other
                  carcinogens, oil and other petroleum products, and any other
                  hazardous or toxic materials, wastes and substances which are
                  defined, determined or identified as such under M.G.L. c. 21E,
                  CERCLA, or any other applicable federal, state or local laws,
                  rules, codes or regulations or any judicial or administrative
                  interpretation thereof; and

            (ii)  The term "Hazardous Waste Law" shall mean all federal, state
                  or local laws, rules, codes or regulations, or any judicial or
                  administrative interpretation thereof, including, without
                  limitation, all orders, decrees, judgments and rulings imposed
                  through any public or private enforcement proceedings relating
                  to Hazardous Materials or the existence, use, discharge,
                  release, containment, transportation or disposal thereof.

      13. Mortgagee's Rights. If Mortgagor shall neglect or refuse to satisfy
any term or condition of this Mortgage or any other document executed in
connection therewith, Mortgagee, at its election, may cause such repairs or
replacements to be made, obtain such insurance or pay said taxes, assessments,
charges and sums, do such acts and incur and pay reasonable amounts in
protecting its rights hereunder and the security hereby granted, pay any balance
due under any conditional agreement of sale of any property included as a part
of the Mortgaged Premises, and pay any amounts as Mortgagee in its discretion
determines to be necessary or appropriate to satisfy any term or condition of
this Mortgage which Mortgagor shall have failed to satisfy, or to remedy any
breach of such term or condition, and any amounts or expenses so paid or
incurred, shall be immediately due and payable by Mortgagor to Mortgagee and
until paid shall be secured by this Mortgage equally and ratably with the other
indebtedness secured hereby, and the same may be collected as part of the
principal debt secured by this Mortgage in any suit hereon or upon the Note or
any other document executed in connection therewith. No such payment or action
by Mortgagee shall relieve Mortgagor from any default hereunder or impair any
right or remedy of Mortgagee with respect thereto.

      14. Certain Expenses. If any action or proceeding be commenced, including
an action to foreclose this Mortgage or to collect the debt hereby secured, to
which action or proceeding Mortgagee is made a party by reason of the execution
of this Mortgage or by reason of any Obligation which it secures, or by reason
of entry or any other action under this Mortgage, or if it becomes necessary in
connection with legal proceedings or otherwise to defend or uphold the mortgage
hereby granted or the lien hereby created or any act taken under this Mortgage,
all reasonable sums paid or incurred by Mortgagee for the expense of any
litigation or otherwise, in connection with any rights created by this Mortgage,
shall be paid by Mortgagor, or may at the discretion of Mortgagee be added to
the Obligations and shall be secured hereby equally and ratably.


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      15. Subrogation. Mortgagee shall, in addition to all other rights, be
subrogated for further security to the lien, whether released of record or taken
by Mortgagee by assignment, of any and all encumbrances on the Mortgaged
Premises or any part thereof to the extent satisfied or acquired by funds of
Mortgagee, whether paid out of the proceeds of the loan secured by this Mortgage
or otherwise.

      16. Acceleration of Debt. Upon the occurrence of a default hereunder or
under the Note, at Mortgagee's discretion, the entire indebtedness and all
Obligations secured hereby shall become immediately due and payable without
further notice or demand.

      17. Additional Rights of Mortgagee upon Mortgagor's Default.

      In the event Mortgagee elects to exercise the statutory power of sale
hereunder, then during such time as Mortgagor remains in possession of the
Mortgaged Premises, Mortgagor agrees and covenants that Mortgagee shall have
access to the Mortgaged Premises, or any portion thereof, for such purposes as
Mortgagee deems necessary or desirable for conducting or planning for the
foreclosure sale, including, without limitation, inspections by surveyors,
appraisers, and structural, environmental and other types of engineers or
building inspection professionals; pre-sale inspections of the Mortgaged
Premises by auctioneers and prospective bidders; and the conduct of the actual
foreclosure auction itself on the Mortgaged Premises. In connection with the
exercise of any such access rights, Mortgagee shall not be deemed to have "taken
possession" of or otherwise be involved with or responsible for the operation or
control of the Mortgaged Premises, such access rights being limited in scope
such as to effectuate the statutory power of sale.

      Mortgagor authorizes Mortgagee, in addition to all other rights granted by
law or by this Mortgage, whenever and as long as any default hereunder shall
exist and remain uncured beyond any applicable grace period, and without notice,
to enter and take possession of all or any part of the Mortgaged Premises and to
use, operate, construct, reconstruct, manage and control the same and perform
lessor's obligations under any lease affecting all or any part of the Mortgaged
Premises, and/or collect the rents, profits and all receipts of every nature
therefrom, as Mortgagee in its discretion shall deem best. Upon every such
entry, Mortgagee may from time to time at the expense of Mortgagor make all such
repairs, replacements, alterations, additions and improvements to the Mortgaged
Premises as Mortgagee in its discretion may deem appropriate and may exercise
all rights and powers of Mortgagor, either in the name of Mortgagor or otherwise
as Mortgagee shall determine. Upon such entry, Mortgagee may, in its discretion,
pay and incur all expenses necessary or deemed by Mortgagee appropriate for the
completion of construction or holding and operating of the Mortgaged Premises,
maintenance, repair, replacement, alteration, addition and improvement of the
Mortgaged Premises, including without limitation payments of taxes, assessments,
insurance, charges and reasonable compensation for services of Mortgagee, its
attorneys and accountants and all other persons engaged or employed in
connection with the Mortgaged Premises and, in addition, Mortgagee, in its
discretion, may make payments or incur liability with respect to obligations
arising prior to the date it takes possession. All obligations so paid or
incurred by Mortgagee shall become part of the Obligations and shall be secured
by this Mortgage equally and ratably with the other indebtedness secured hereby
or deducted from the income or receipts of the Mortgaged Premises.


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      18. Power of Sale. This Mortgage is upon the STATUTORY CONDITION and upon
the further condition that all covenants and agreements of Mortgagor contained
herein and in the Note and every other document executed in connection therewith
shall be kept and fully performed, for any breach of which Mortgagee shall have
the STATUTORY POWER OF SALE and all rights under Massachusetts law.

      In exercising its power of sale under this Mortgage, Mortgagee may sell
the Personal Property, or any part thereof, either separately from or together
with the Real Estate or any part thereof, either as one unit or in separate
units, all as Mortgagee may in its discretion elect; and may also sell the
Mortgaged Premises as one unit or parcel or in such separate units or parcels as
Mortgagee may in its discretion elect; and may so sell the Mortgaged Premises or
any part thereof either separately from or together with the whole or any part
of other collateral which may constitute security for any Obligation, also as
Mortgagee may in its discretion elect. Without limiting the generality of the
foregoing, Mortgagee's statutory power of sale shall not be exhausted until all
of the Real Estate shall have been struck down at a foreclosure auction and the
successful bidders have all accepted and recorded the resulting foreclosure
deeds, it being expressly agreed that Mortgagee shall have the power to
foreclose upon and sell portions of the Real Estate at different times or days
if Mortgagee so elects and Mortgagee also may continue to auction the Real
Estate at any foreclosure sale even if the amounts previously struck down at
prior foreclosure auction sales for other portions of the Real Estate exceed the
Obligations (provided Mortgagee duly accounts for the excess proceeds in
accordance with applicable law). In the event of any separate sale of the
Personal Property, Mortgagee will give to Mortgagor reasonable notice of the
time and place of any public sale or of the time after which any private sale or
other intended disposition thereof is to be made, and such requirement of
reasonable notice shall be met if such notice is given at least ten (10) days
before the time of the sale or other disposition.

      19. Waiver by Mortgagor. Mortgagor, to the fullest extent that Mortgagor
may do so, hereby: (a) agrees that Mortgagor will not at any time insist upon,
plead, claim or take the benefit or advantage of any law now or hereafter in
force providing for any appraisement, valuation, stay, extension or redemption,
and waives and releases all rights of redemption, valuation, appraisement, stay
of execution, notice of election to mature or declare due the Obligations; and
(b) waives all rights to a marshalling of the assets of Mortgagor, including
without limitation the Mortgaged Premises, or to a sale in inverse order of
alienation in the event of a sale hereunder of the Mortgaged Premises, and
agrees not to assert any right under any statute or rule of law pertaining to
the marshalling of assets, sale in inverse order of alienation, or other matters
whatever to defeat, reduce or affect the right of Mortgagee under the terms of
this Mortgage or the Note or any other document executed in connection herewith,
to a sale of the Mortgaged Premises for the collection of the indebtedness
evidenced by the Note and all other Obligations without any prior or different
resort for collection, or the right of Mortgagee to the payment of such
indebtedness and other Obligations out of the proceeds of sale of the Mortgaged
Premises in preference to every other claimant whatever.


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      20. Notices. All notices, demands, and other communications made with
respect to this Mortgage or any other document executed in connection therewith
shall be in writing and given by hand, by telegram, by Federal Express, Express
Mail or any other nationally recognized overnight delivery service, by
telecopier (provided a copy is also sent via first class mail) or by certified
or registered first class mail, return receipt requested, postage prepaid, and
sent to the addresses set forth on the first page hereof. Each of the foregoing
addresses may be changed upon fifteen (15) days' prior written notice given by
any of the foregoing prescribed methods. All notices shall be deemed received on
the earliest of (i) actual receipt; (ii) the date on which the notice was
delivered by hand, telecopier, or telegram; or (iii) two (2) business days after
sending such notice otherwise in accordance with the foregoing provisions.

      21. Mortgagee not Obligated; Cumulative Rights. Nothing in this Mortgage
shall be construed as obligating Mortgagee to take any action or incur any
liability with respect to the Mortgaged Premises, and all powers given to
Mortgagee are for its benefit and shall be exercised in Mortgagee's discretion,
as indicated herein. All of Mortgagee's rights hereunder are cumulative and in
addition to, and not in substitution for, the rights of Mortgagee under all
other documents executed in connection herewith. In the event of a conflict
between the rights of Mortgagee hereunder and the rights of Mortgagee under any
other document, Mortgagee may elect, at its sole discretion, to exercise any
such rights in such order and combinations as it deems appropriate. Likewise,
Mortgagor's obligations hereunder are cumulative and are in addition to and not
in substitution for the obligations of Mortgagor under all other documents. In
the event of a conflict between the obligations of Mortgagor hereunder and the
obligations of Mortgagor under any other document, Mortgagor shall perform and
adhere to those obligations most favorable to Mortgagee and most restrictive
upon Mortgagor.

      22. Maximum Amount Secured. The maximum amount secured by this Mortgage
shall include the total of all of the following items which may be outstanding
at any time: principal; interest; legal fees; collection and foreclosure costs
(including appraisals, environmental testing (and remediation, if necessary),
brokerage commissions, commercial advertising costs, and auctioneer fees); all
taxes, insurance premiums, maintenance costs or other amounts advanced by
Mortgagee for purpose of protecting its security; all other Obligations of
Mortgagor to Mortgagee; and all other damages and costs to which the holder of a
mortgage is entitled under applicable law.


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<PAGE>

      23. Receiver. Whether or not Mortgagor is then insolvent, any rights of
Mortgagee hereunder may be exercised by a court appointed receiver. In
connection therewith, such a receiver shall be appointed upon a petition filed
by Mortgagee with any court of competent jurisdiction and, effective after the
occurrence of an event of default, Mortgagor hereby consents to and approves of
such appointment and waives any right to object thereto.

      24. Mortgage Tax. If any law is hereafter passed which imposes a stamp,
documentary or other similar tax on the Note, this Mortgage, or the obligations
secured hereby, Mortgagor shall pay the same within ten (10) days after demand
by Mortgagee.

            This Mortgage shall inure to the benefit of and be binding upon
Mortgagor and Mortgagee and their respective representatives, successors and
assigns. The terms "Mortgagor" and "Mortgagee" as used herein shall include all
subsequent holders of their respective rights, title and interests under this
Mortgage.

                 [The next succeeding page is a signature page.]


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<PAGE>

      EXECUTED as a sealed instrument under Massachusetts's law as of date first
noted above.

                                        MORTGAGOR:

                                        /s/ Linda J. Isaacson
                                        ------------------------------------
                                        LINDA J. ISAACSON, AS TRUSTEE
                                        OF THE RASHI REALTY TRUST DATED
                                        FEBRUARY 22, 1991

                                        /s/ Mark S. Isaacson
                                        -----------------------------------
                                        MARK S. ISAACSON, AS TRUSTEE
                                        OF THE RASHI REALTY TRUST DATED
                                        FEBRUARY 22, 1991

                          COMMONWEALTH OF MASSACHUSETTS

____________, ss.                                                  April 3, 2001

      Before me personally appeared the above-named Linda J. Isaacson, and Mark
S. Isaacson, as Trustees of the Rashi Realty Trust Dated February 22, 1991, to
me known to be the persons described herein and who executed the foregoing
instruments, and acknowledged that they executed the foregoing instrument as
their free act and deed on behalf of the Trust.

                                         ________________________, Notary Public

                                         My Commission Expires:


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