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                                                        EXHIBIT 10.4


                    [MINNEAPOLIS WEST BUSINESS CENTER LOGO]

                                     LEASE


This Lease is entered into as of August 16, 1996, between MEPC AMERICAN
PROPERTIES INC., a Delaware corporation ("Lessor") and RINGER CORPORATION, a
Minnesota corporation, ("Tenant").

1. Definitions. In this Lease:

        (a)     "Building" means that certain office/warehouse building
                containing approximately 96,800 square feet of net rentable
                area known as Trapp Road Community Building I located on the 
                Land Eagandale Center, known as Suite 190, 1279 Trapp Road in 
                the of Eagan, Minnesota.

        (b)     "Premises" means that certain portion of the Building designated
                as Bays 12 - 15, which space is shown crosshatched on the 
                drawing attached to this Lease as Exhibit A and is estimated to 
                contain 1,234 square feet of office and 25,358 square feet of 
                warehouse for a total of 26,592 square feet.

        (c)     "Office Space" means that portion of the Premises, based upon
                the final floor plan for the Premises, constructed for purposes
                of office use and designated as such in the supplemental 
                agreement referred to in Section 2.

        (d)     "Warehouse Space" means that portion of the Premises, based
                upon the final plan for the Premises, constructed for purposes
                of manufacturing, production or warehouse use and designated as
                such in the supplemental agreement referred to in Section 2.

        (e)     "Term" means the period of 5 years and no months, beginning on 
                January 1, 1997 and ending on December 31, 2001, subject to the
                provisions of Sections 2 and 7 and the other provisions of this
                Lease.

        (f)     "Commencement Date" means the earlier of the date on which 
                Tenant opens for business in the Premises or the date on which
                Lessor has substantially completed Lessor's Work as evidenced
                by a Certificate of Substantial Completion issued by Lessor's
                architect or a Certificate of Occupancy issued by the City 
                of Eagan.

        (g)     "Lease Year" means a period of 12 consecutive months commencing
                on the first day of the first full month of the Term and each 
                12-month  period thereafter during the Term.

        (h)     "Monthly Base Rent" means the following amounts per Rentable
                Square Foot multiplied by the number of Square Feet of Office
                Space and Warehouse Space in the Premises divided by 12:

              <TABLE>
              <CAPTION>
               
                Lease Year       Office Space Rate      Warehouse Space Rate
               -----------      -------------------    ----------------------  
               <S>               <C>                    <C>
               1 through 5        $8.00                  $4.00
              
               </TABLE>


                After the Monthly Base Rent is determined, the amount of the 
                Monthly Base Rent will not change during the Term unless space 
                is added to or deleted from the Premises as provided in this 
                Lease or by written amendment to this Lease.




                


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        (I)     "Costs" means the estimated monthly Tax Costs plus the
                estimated monthly Operating Costs.

        (j)     "Monthly Rent" means the Monthly Base Rent plus Tenant's
                Share of the Costs.

        (k)     "Tenant's Share" means the percentage obtained by dividing the
                Square Feet of the Premises by the Square Feet in the Building,
                which percentage on the date of this Lease is estimated to be
                27.47% based on the number of square feet stated in 
                paragraph (b) above and based upon a current estimated of the
                Square Feet in the Building of 96,800 square feet.

        (l)     "Operating Costs" means all costs, charges and expenses incurred
                by Lessor in connection with ownership, operation, security,
                maintenance and repair of the Land, the Building, other
                improvements on the Land, appurtenances to the Building,
                parking, roadways, landscaping, lighting, sidewalks, and common
                or public areas, including but not limited to real estate taxes
                and insurance on Common Areas, interior and exterior
                maintenance, insurance, utilities, fees or expenses for
                management by Lessor or any other party, amortization of capital
                investments made to reduce Operating Costs, or required under
                any governmental law or regulation which was not applicable to
                the Building at the time it was constructed, and amortization of
                repairs made to extend the life of the Building and other
                improvements. Operating Costs will not include mortgage
                interest, depreciation on the Building or fixtures, advertising
                expenses, real estate brokers' commissions or the cost of tenant
                improvements.

        (m)     "Tax Costs" means all real estate taxes, levies, charges, and 
                installments of assessments (including interest on deferred
                assessments) assessed, levied or imposed on, or allocated to,
                the Land and Building and all attorney's fees, consultants'
                fees, witness fees, court costs and other expenses of Lessor
                in connection with any proceeding to contest these amounts.

        (n)     "Square Feet" means the number of square feet calculated from
                dimensional architect's drawings by measuring to the outside
                surface of exterior walls and to the centerline of walls 
                separating areas leased or held for lease to others.

        (o)     "Lease" means this Lease, all Exhibits attached to this Lease,
                and all properly executed amendments, modifications and
                supplements to this Lease.

        (p)     "Section" means a section of this Lease.

        (q)     "Exhibit" means an Exhibit attached to and thereby made a part
                of this Lease.

        (r)     "Land" means the land described on Exhibit B.

        (s)     "Taking" means acquisition by a public authority having the 
                power of eminent domain of all or part of the Land or Building
                by condemnation or conveyance in lieu of condemnation.

        (t)     "Casualty" means a fire, explosion, tornado, or other cause of 
                damage to or destruction of the Building.


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        (u)     "Lessor's Work" means the work described in the plans and
                specifications identified in Exhibit D to be provided by Lessor
                at its expense.

        (v)     "Common Areas" means any halls, lavatories, loading facilities,
                driveways and open lot parking areas, designed for the
                nonexclusive use of the owner and occupants of the Building,
                and not designed or intended for the exclusive use of a single
                tenant, as designated by Lessor from time to time.

        (w)     "Tenant's Work" means all improvements, alterations, fixtures
                and equipment other than the Lessor's Work constructed or
                installed for Tenant's use and occupancy of the Premises or
                desired by Tenant to complete the Premises for occupancy.

2. Premises and Construction.

Lessor leases the Premises to Tenant, and Tenant leases the Premises from
Lessor, for the Term, under the terms and conditions of this Lease.

Lessor will be responsible for the design and construction of the Building. The
Premises will be constructed by Lessor in accordance with Exhibit D. All work
will be designed, performed, completed and paid for as provided in Exhibit D.
Any other work desired by Tenant to complete the Premises for occupancy will be
performed by Lessor at Tenant's sole expense.

When Tenant takes possession of all or a portion of the Premises, that will be
deemed conclusive evidence that the Premises or the portion are in satisfactory
condition on that date, and that Lessor has completed all work for which it is
responsible, subject only to latent defects and to deficiencies (if any) listed
in a written notice delivered by Tenant to Lessor not more than 30 days after
the date of taking possession.

Within 60 days after the Commencement Date, Lessor and Tenant will execute an
agreement supplementing this Lease setting forth: the Commencement Date and
expiration date of the Term, the "as-built" Square Feet of the Premises and
Square Feet in the Building, the Monthly Base Rent, and the Tenant's Share 
percentage.

3. Rent.

Tenant will pay the Monthly Rent to Lessor at P.O. Box 73547, Chicago, Illinois
60673-7547, or such other place as Lessor may designate, in advance on the
first day of each month during the Term, without demand, deduction or setoff.
The Monthly Rent may change as the Costs are adjusted annually under Sections 4
and 5. Monthly Rent will begin on the Commencement Date. If the Term begins on
a day other than the first day of a month, the Monthly Rent for that month will
be prorated by multiplying the Monthly Rent by the number of days of that month
included in the Term and dividing the product by the number of days in 
that month.

Any Monthly Rent or other amounts payable by Tenant to Lessor under this Lease
which are not paid within 10 days after the date due will bear interest from
the date due to the date paid at the rate of 18% per annum or the maximum rate
of interest permitted by law, whichever is less, and the interest will be paid
to Lessor on demand. In addition, Tenant will pay Lessor a $100 service charge
for all Monthly Rent not paid by the 10th day of the month for which it is
payable, which service charge is to partially cover expense involved in
handling delinquent payments. All amounts to be paid by Tenant to Lessor under
this Lease will be deemed to be additional rent for purposes of payment and 
collection.
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If any taxes, special assessments, fees or other charges are imposed against
Lessor by any governmental unit or agency with respect to rentals under this
Lease, Tenant will pay these amounts to Lessor when due, except that Tenant
will have no obligation to pay any income tax on rentals unless the tax is
imposed in lieu of real estate taxes.

4. Cost Adjustments.

The initial Monthly Rent is based in part on the estimated Operating Costs and
Tax Costs. Prior to the first day of each calendar year after the date of this
Lease, or as soon as reasonably possible after the first day of the year,
Lessor will furnish Tenant with an estimate of the Costs if greater than the
initial Costs, and the Monthly Rent will be increased by 1/12th of Tenant's
Share of the difference between the initial estimate of Costs and the current 
estimate.

After the end of each calendar year, including the year in which the Term
expires, Lessor will give Tenant a statement of the actual Costs for that
calendar year. If the actual Costs exceed the estimated Costs for that year,
Tenant will pay Tenant's Share of the excess to Lessor within 20 days after
receiving the statement. If the actual Costs are less than the estimated Costs
for that year, Lessor will pay Tenant's Share of the difference to Tenant with
the statement. If Tenant does not give Lessor written notice within one year
after receiving Lessor's statement that Tenant disagrees with the statement and
specifying the amounts in dispute, Tenant will be deemed to have waived the
right to contest the statement. Tenant will file no petition in Tax Court
regarding the Tax Costs without Lessor's prior written consent. If Lessor
contests Tax Costs and receives a refund or incurs additional Tax Costs after
adjustments for actual Tax Costs have been made, the actual Tax Costs will be
corrected accordingly and the appropriate adjustment will be made between
Lessor and Tenant. The portion of Costs to be paid by Tenant for the years in
which the Term begins and ends will be prorated by multiplying the actual Costs
by a fraction, the numerator of which is the number of days of that year in the
Term and the denominator of which is 365.

5. Cost Computations and Allocations.

Notwithstanding any other provision of this Lease to the contrary, it is agreed
that Lessor will in its reasonable discretion, determine from time to time, the
method of computing and allocating Costs, the allocation of Costs to various
types of space within the Building, and Tenant will be bound thereby. If the
Building is not fully occupied during any partial or full year, an adjustment
will be made in computing the actual Operating Costs for such year so that it
is computed as though the Building had been fully occupied during that year.

6. Fiscal Year.

The year used to determine Costs may be changed to a different 12-month period
designated by Lessor. If the calendar year is changed to a fiscal year, or if a
fiscal year is changed to a different fiscal year, prorations will be made for
the estimated Costs and the actual Costs so that the same time period is used
to determine each and so that Costs are not included in more than one time 
period.

7. Possession.

If Tenant begins to conduct business in all or any portion of the Premises
before the Commencement Date, Tenant will pay to Lessor Monthly Rent for the
period from the date Tenant begins to conduct business in the Premises to the
Commencement Date and all other provisions of this Lease will be applicable
during that period.

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If Lessor is delayed in delivering possession of all or any portion of the
Premises to Tenant on the Commencement Date, Tenant will take possession of the
Premises on the date when Lessor delivers possession of all of the Premises,
which date will then become the Commencement Date, and the last day of the term
will be extended so that the length of the Term remains the same. If the
extended Term would end on a day other than the last day of a month, the Term
will be further extended to the last day of the month in which the Term ends.

This Lease will not be void or voidable and Lessor will not be liable to Tenant
for any loss or damage resulting from any delay in delivering possession of the
Premises to Tenant, but unless the delay is principally caused by or
attributable to Tenant, its employees, agents or contractors, no Monthly Rent
will be due for the period prior to the date Lessor delivers possession of the
Premises, unless Tenant elects to take possession of a portion of the Premises,
in which case Monthly Rent will be due for the portion of the Premises taken.
Tenant's occupancy of the Premises will constitute Tenant's acceptance of the 
Premises.

If Tenant pays the Monthly Rent and other charges and performs all of Tenant's
obligations under this Lease, Lessor promises that Tenant may peaceably and
quietly possess and enjoy the Premises under this Lease.

8.  Use.

Tenant will use the Premises for 1,234 square feet for general business office
and 25,358 square feet of general warehouse use and for no other purpose.
Tenant will not commit or permit any act or omission which results in the
violation of any law, governmental regulation, or insurance policy of Lessor,
relating to the Building, or which will increase Lessor's insurance rates on
the Building. Tenant will not permit any conduct or condition which may unduly
disturb or endanger other occupants of the Building.

9.  Care of Premises.

Tenant will, at all times during the Term and any renewals and extensions, at
its sole expense, keep and maintain the Premises in a clean, safe, sanitary,
and first class condition and in compliance with all applicable laws, codes,
ordinances, rules, and regulations. Tenant's obligations will include but not
be limited to the maintenance, repair and replacement, if necessary, of
heating, air conditioning and ventilating fixtures, equipment and systems, all
lighting and plumbing fixtures, all interior walls, partitions, doors and
windows, including the regular painting thereof, all exterior entrances,
windows, doors, and docks and the replacement of all broken glass. When used in
this Section, the term "repairs" shall include replacements and overhauling
equipment when necessary, and all such repairs made by the Tenant shall be
equal in quality and class to the original work. The Tenant shall keep and
maintain all portions of the Premises and the sidewalk and areas adjoining the
same in clean and orderly condition, free of accumulation of dirt, rubbish,
snow, and ice.

If Tenant fails, refuses or neglects to maintain or repair the Premises as
required in this Lease after notice has been given Tenant, Lessor may make such
repairs without liability to Tenant for any loss or damage that may accrue to
Tenant's merchandise, fixtures, or other property or to its business, and upon
completion, Tenant will pay to Lessor all costs plus 15% for overhead incurred
by Lessor in making such repairs upon presentation to Tenant of bill for the 
repairs.

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Lessor will repair, at its expense, the structural portions of the Building
provided, however, where structural repairs are required to be made by reason
of the acts of Tenant, the costs will be reimbursed by Tenant and payable by
Tenant to Lessor upon demand.

Tenant, at its own cost and expense, will enter into a regularly scheduled
preventive maintenance and service contract with a maintenance contractor
approved by Lessor for servicing all hot water, heating and air conditioning
systems and equipment within the Premises. The service contract must include
all services suggested by the equipment manufacturer in its operations and
maintenance manual and must become effective within 30 days of the date Tenant
takes possession of the Premises.

10. Building Rules.

Rules and Regulations for the Premises and the Building in effect on the date
of this Lease are attached as Exhibit C. Lessor will have the right to adopt
different or additional reasonable rules and regulations, and to rescind or
amend the attached rules and regulations, from time to time. Tenant will abide
by the rules and regulations then in force and will cause Tenant's employees to
observe and comply with them.

11. Compliance with Laws.

Tenant will, at its expense, promptly comply with all laws, ordinances, rules,
orders, regulations and other requirements of governmental authorities now or
subsequently pertaining to the Premises. Tenant will pay any taxes or other
charges by any governmental authority on Tenant's property or trade fixtures in
the Premises or relating to Tenant's use of the Premises.

The Premises shall not be used in any manner which under any requirement of law
or of any public authority would require Lessor to make any addition or
alterations to or in the Building. After the construction of any initial
improvements by Lessor in the Premises, Tenant will be responsible for
compliance with the Americans with Disabilities Act of 1990 as it applies to
the Premises. The Premises shall not be used in any manner which will increase
the rates required to be paid for public liability  or for all risk insurance
covering the Building. Tenant shall occupy the Premises, conduct its business
and control its agents, employees, invitees, and visitors in such a way as is
lawful and reputable and will not permit or create any nuisance, noise, odor,
or otherwise interfere with, annoy, or disturb any other Tenant in the Building
in its normal business operations or Lessor in its management of the Building.
Outside storage on the Land of any type of equipment, property, or materials
owned or used by Tenant or its customers and suppliers is not permitted.

12. Hazardous Substances.

The term "Hazardous Substances", as used in this Lease, means pollutants,
contaminants, toxic or hazardous wastes or any other substances, the removal of
which is required or the use of which is restricted, prohibited or penalized by
an "Environmental Law", which term means any federal, state or local law or
ordinance relating to pollution or the protection of the environment. Tenant
agrees that (a) no activity will be conducted on the Premises that will produce
any Hazardous Substance, except for activities which are part of the ordinary
course of Tenant's business (the "Permitted Activities"), provided the
Permitted Activities are conducted in accordance with all Environmental Laws
and have been approved in advance in writing by Lessor; (b) the Premises will
not be used for storage of any Hazardous Substances, except for temporary
storage of materials used in the Permitted Activities (the "Permitted
Materials"), provided the Permitted Materials are properly stored in a manner
and location meeting all Environmental Laws and approved in advance in writing
by Lessor; (c) no portion of the Premises or Land will be used by Tenant as a
landfill or a dump; (d) Tenant will not install any underground tanks of any
type; (e) Tenant will not cause any surface or subsurface conditions to exist
or come into existence that constitute, or with the passage of time may
constitute, a public or private nuisance; (f) Tenant will not permit any
Hazardous Substances to be brought onto the Premises, except for Permitted
Materials, and if so brought or found, Tenant will immediately remove them,
with proper disposal, and will undertake all required cleanup procedures under
the Environmental Laws. If, at any time during or after the term of the Lease,
the Premises are found to be contaminated or subject to conditions prohibited
in this Lease, Tenant will indemnify and hold Lessor harmless from all claims,
demands, actions, liabilities, costs, expenses, damages
<PAGE>   7
and obligations of any nature arising from or as a result of the use of the
Premises by Tenant. The foregoing indemnification will survive the termination
or expiration of this Lease.

13. Signs.

Tenant will not place or permit any signs on the exterior or windows of the
Building, or within the Premises if visible from the exterior of the Building
or from hallways or other Common Areas of the Building, except lettering and
numerals for identification purposes on or near doorways as approved in advance
by Lessor. Lessor agrees that Tenant will be entitled to two (2) identification
signs on the north and south exterior of the Building, subject to (i) Lessor's
approval of the size, location, type and design of the sign, (ii) compliance
with all applicable laws, ordinances and regulations, and (iii) Tenants payment
of all costs relating to such signage.

14. Alterations.

After completion of the Building and the Premises, Lessor will have no
obligations to do any redecorating or remodeling or to make any repairs or 
alterations.

Tenant will not make any alterations, additions or improvements in or to the
Premises without first obtaining the written consent of Lessor. Tenant will get
Lessor's prior written approval of any contractor or subcontractor who is to
perform work on the Premises at Tenant's request. Lessor may require Tenant to
post a bond, cash or other security to protect the Premises from mechanic's
liens. All alterations by Tenant will be constructed with new materials, in a
good and workmanlike manner, and in compliance with the plans and
specifications approved by Lessor and all applicable laws, ordinances, rules,
orders, regulations, or other requirements of governmental authorities. Tenant
will pay for any labor, services, materials, supplies or equipment furnished or
alleged to have been furnished to Tenant in or about the Premises, and will pay
and discharge any mechanic's, materialmen's or other lien against the Premises
resulting from Tenant's failure to make such payment, or will contest the lien
and deposit with Lessor cash equal to 150% of the amount of the lien. If the
lien is reduced to final judgment, Tenant will discharge the judgment and
Lessor will return the cash deposited by Tenant. Lessor may post notices of
nonresponsibility on the Premises as provided by law.

All alterations, additions and improvements to the Premises made at Lessor's or
Tenant's expense, except movable office furniture and Tenant's movable trade
fixtures and equipment, will become the property of Lessor upon installation
and will be surrendered with the Premises upon termination of this Lease unless
Lessor elects otherwise in writing.

15. Utilities and Services.

Lessor will provide mains and conduits to supply water, gas, electricity and
sanitary sewer services to the Premises. Tenant will pay all charges for sewer
usage, garbage disposal, refuse removal, water, electricity, gas, heating, air
conditioning and ventilation costs, telephone, and any other utility services
furnished to the Premises during the Term. If any of such services are
furnished by Lessor, the cost of all such services furnished by Lessor will be
a part of the Operating Costs. Lessor will not be liable for any loss or damage
resulting from any temporary interruption of these services due to repairs,
alterations or improvements, or any variation, interruption or failure of these
services due to governmental controls, unavailability of energy, or any other
cause beyond Lessor's control. No such interruption or failure of these
services will be deemed as an eviction of Tenant or will relieve Tenant from
any of its obligations under this Lease.

16. Entry by Lessor.

Lessor and its agents and contractors and mortgagees will have the right to
enter the Premises at reasonable times for inspecting, cleaning, repairing, or
exhibiting the Premises, by Lessor will have no obligation to make repairs,
alterations or improvements except as expressly provided in this Lease.


<PAGE>   8
17.  Subordination.

At the request of any mortgagee or ground lessor, this Lease will be subject
and subordinate to any mortgage or ground lease which may now or hereafter
encumber the Building, and Tenant will execute, acknowledge and deliver to
Lessor any document requested by Lessor to evidence the subordination. Such
subordination is on the condition that Tenant's right of possession of the
Premises as provided in this Lease will not be disturbed by the mortgagee or
ground lessor so long as Tenant is not in default under this Lease. If the
interest of Lessor is transferred to any party by reason of foreclosure of a
mortgage or cancellation of a ground lease, or by delivery of a deed in lieu of
foreclosure or cancellation, Tenant will immediately and automatically attorn
to such party. Tenant agrees that upon notification by Lessor or any mortgagee
or ground lessor of the election of a mortgagee or ground lessor to subordinate
its interest in the Premises to this Lease, this Lease will become prior to the
mortgage or ground lease.

18.  Estoppel Certificates.

Within 10 business days after written request from Lessor, Tenant will execute,
acknowledge and deliver to Lessor a document furnished by Lessor, which
document may be relied upon by Lessor and any prospective purchaser or
mortgagee of the Building, stating (a) that this Lease is unmodified and is in
full force and effect (or if modified, that the Lease is in full force and
effect as modified and stating the modifications), (b) the dates to which rent
and other charges have been paid, (c) the current Monthly Rent, (d) the dates
on which the Term begins and ends, (e) that Tenant has accepted the Premises
and is in possession, (f) that Lessor is not in default under this Lease, or,
if Lessor is in default, specifying any such default, and (g) including such
other information as the prospective purchaser or mortgagee may require.

19.  Waiver of Claims and Assumption of Risks.

Lessor and Tenant release each other from any liability for loss or damage by
fire or other casualty coverable by a standard form of "all risk" insurance
policy, whether or not the loss or damage resulted from the negligence of the
other, its agents or employees. Each party will use reasonable efforts to
obtain policies of insurance which provide that this release will not adversely
affect the rights or the insureds under the policies. The releases in this
Section will be effective whether or not the loss was actually covered by
insurance. Tenant assumes all risk of loss or damage of Tenant's property
within the Premises, including any loss or damage caused by water leakage,
fire, windstorm, explosion, theft, act of any other tenant, or other cause.
Lessor will not be liable to Tenant, or its employees, for loss of or damage to
any property in the Premises.

20.  Indemnification.

Tenant will indemnify Lessor and its agents and employees against all claims,
demands and actions, and all related costs and expenses (including attorneys'
fees) for injury, death, disability or illness of any person, or damage to
property, occurring in the Premises or arising out of Tenant's use of the
Premises, except to the extent caused by the willful misconduct or negligence
of Lessor or someone acting on its behalf.

21.  Insurance.

Tenant will keep public liability insurance in force at its expense by an
insurer and policy acceptable to Lessor in its reasonable opinion. The policy
will name Lessor and its mortgagee as additional insureds, for limits of at
least $1,000,000 for bodily injuries or death of one or more persons and at
least $500,000 for property damage. Tenant will carry fire and "all risk"
coverage insurance for Tenant's property and improvements in this Premises.
Prior to Tenant's occupancy of the Premises, Tenant will deliver to Lessor the
liability and casualty policies or certificates by the insurer showing this
coverage to be in effect with premiums paid. The insurance will provide that
Lessor will be notified in writing 30 days prior to cancellation of, material
change in, or failure to renew, the insurance.
<PAGE>   9
22. Assignment and Subletting.

Tenant may assign this Lease or sublet all or part of the Premises only with
Lessor's prior written consent. If Tenant receives a bona fide offer for an
assignment of Tenant's interest under this Lease or to sublease all or part of
the Premises and Tenant requests Lessor's consent, a copy of the offer will be
furnished to Lessor. In the case of a proposed assignment or sublease of all of
the Premises, Lessor may terminate this Lease, either conditioned on execution
of a new lease between Lessor and the party making the offer on the same terms
as the offer to Tenant or without that condition. In the case of a proposed
sublease for less than all of the Premises, Lessor may amend this Lease to
exclude the portion of the Premises to be subleased, either conditioned on
execution of a new lease between Lessor and the party making the offer on the
same terms as in the offer to Tenant or without that condition.

If Lessor fails to give Tenant written notice of its decision to terminate or
amend this Lease within 15 days after receiving a copy of the offer to Tenant,
Lessor will not unreasonably withhold its consent to the assignment or sublease
described in the offer. The provisions of this Section will be binding on
Tenant and any assignee or subtenant of Tenant and will apply to all portions
of the Premises remaining subject to this Lease and to each request by Tenant,
or its assignee or subtenant, for Lessor's consent to a further or subsequent
assignment or subletting.

If Lessor consents to one or more assignments or subleases, Tenant will still
remain liable for all obligations of the Tenant under this Lease.

Lessor's interest in this Lease will be freely assignable and the obligations
of the Lessor arising or accruing under this Lease after an assignment will be
enforceable only against the assignee.

23. Damage or Destruction.

If the Premises or Building is damaged by Casualty, the damage (excluding
damage to improvements paid for by Tenant or trade fixtures, equipment or
personal property of Tenant) will be repaired by Lessor at its expense to a
condition as near as reasonably possible to the condition prior to the
Casualty, but if more than 25% of the total Square Feet in the Building is
rendered untenantable, Lessor may terminate this Lease as of the date of the
Casualty by giving written notice to Tenant within 30 days after the Casualty.
If this Lease is not terminated, Lessor will begin repairs within 90 days after
the Casualty and complete the repairs within a reasonably time, subject to acts
of God, strikes and other matters not within the control of Lessor. If Lessor
fails to begin and proceed with repairs as required, Tenant may give Lessor
notice to do so. If Lessor has not begun the repairs within 30 days after
Tenant's notice, Tenant may terminate this Lease by written notice to Lessor
within 15 days after expiration of the 30-day period. If this Lease is
terminated because of the Casualty, rents and other payments will be prorated
as of the termination and will be proportionately refunded to Tenant or paid to
Lessor, as the case may be. During any period in which the Premises or any
portion of the Premises is made untenantable as a result of the Casualty, the
Monthly Rent will be abated for the period of time untenantable in proportion
to the square foot area untenantable.

24. Eminent Domain.

If there is a Taking of 25% or more of the Premises or 25% or more of the total
Square Feet in the Building, either party may terminate this Lease as of the
date the public authority takes possession, by written notice to the other
party within 30 days after the Taking. If this Lease is so terminated, any
rents and other payments will be prorated as of the termination and will be
proportionately refunded to Tenant, or paid to Lessor, as the case may be. All
damages, awards and payments for the Taking will belong to Lessor irrespective
of the basis upon which they were made or awarded, except that Tenant will be
entitled to any amounts specifically awarded for Tenant's trade fixtures or
equipment or as a relocation payment or allowance. If this Lease is not
terminated as a result of the Taking, Lessor will restore the remainder of the
Premises to a condition as near as reasonably possible to the condition prior
to the Taking, the rent will be abated for the period of time the space is
untenantable in proportion to the square foot area untenantable and this Lease
will be amended appropriately to reflect the deletion of the space taken.
<PAGE>   10
25. Defaults.

If (a) Tenant defaults in the payment of rent or other amounts under this Lease
and the default continues for 10 days after written notice by Lessor to Tenant,
(b) Tenant defaults in any other obligation under this Lease and the default
continues for 30 days after written notice by Lessor to Tenant, (c) any
proceeding is begun by or against Tenant to subject the assets of Tenant to any
bankruptcy or insolvency law or for an appointment of a receiver of Tenant or
for any of Tenant's assets, or (d) Tenant makes a general assignment of
Tenant's assets for the benefit of creditors, then Lessor may, with or without
terminating this Lease, cure the default and charge Tenant all costs and
expenses of doing so, and Lessor also may reenter the Premises, remove all
persons and property, and regain possession of the Premises, without waiver or
loss of any of Lessor's rights under this Lease, including Lessor's right to
payment of Monthly Rent. Lessor also may terminate this Lease as to all future
rights of Tenant, without terminating Lessor's right to payment of Monthly Rent
and other charges due under this Lease.

Tenant waives any right of restoration to possession of the Premises after
reentry, notice of termination, or after judgment for possession. If this Lease
is terminated under this Section, Tenant promises and agrees to pay all Monthly
Rent and other charges due for the remainder of the original Term, and all
attorneys' fees and other expenses. If Tenant defaults in any of its
obligations under this Lease, it will promptly pay all costs (including
attorneys' fees) of enforcing Tenant's obligations, whether or not this Lease
is terminated and whether or not suit is brought. No right or remedy will
preclude any other right or remedy, no right or remedy will be exclusive of or
dependent upon any other right or remedy, and any right or remedy may be
exercised independently or in combination.

If Tenant is in default and notice of termination of Tenant's right to
possession has been mailed to Tenant at the Premises and it appears in
Lessor's reasonable judgment that Tenant has abandoned or vacated the Premises,
Lessor may reenter the Premises and retake possession without legal action,
without relieving Tenant of the obligation to pay Monthly Rent or any other
obligations under this Lease, and without any liability to Tenant for re-entry
removal of Tenant's property.


26. Waiver of Lease Provisions.

No waiver of any provision of this Lease will be deemed a waiver of any other
provision or a waiver of that same provision on a subsequent occasion. The
receipt of rent by Lessor with knowledge of a default under this Lease by
Tenant will not be deemed a waiver of the default. Lessor will not be deemed to
have waived any provision of this Lease by any action or inaction and no waiver
will be effective unless it is done by expressed written agreement signed by
Lessor. Any payment by Tenant and acceptance by Lessor of a lesser amount than
the full amount of all Monthly Rent and other charges then due will be applied
to the earliest amounts due. No endorsement or statement on any check or letter
for payment of rent or other amount will be deemed an accord and satisfaction,
and Lessor may accept such check or payment without prejudice to its right to
recover the balance of any rent or other amount or to pursue any other remedy
provided in this Lease. No acceptance of payment of less than the full amount
due will be deemed a waiver of the right to the full amount due together with
any interest and service charges.

27. Return of Possession to Lessor.

On expiration of the Term or sooner termination of this Lease, Tenant will
return possession of the Premises to Lessor, without notice from Lessor, in
good order and condition, except for ordinary wear and damage, destruction or
conditions Tenant is not required to remedy under this Lease. If Tenant does
not return possession of the Premises to Lessor, Tenant will pay Lessor all
resulting damages Lessor may suffer and will indemnify Lessor against all
claims made by any new tenant of all or any part of the Premises. Tenant will
give Lessor all keys for the Premises and will inform Lessor of combinations on
any locks and safes on the Premises. Any property left in the Premises after
expiration or termination of this Lease or after the Premises have been vacated
by Tenant will become the property of Lessor to dispose of as Lessor chooses.

<PAGE>   11
28.  Holding Over.

If Tenant remains in possession of the Premises after expiration of the Term
without a new lease, it may do so only with written consent by Lessor, and any
such holding over will be from month-to-month subject to all the same
provisions of this Lease, except that the Monthly Base Rent will be the Monthly
Base Rent stated in Lessor's consent if a new Monthly Base Rent is stated, or
double the Monthly Base Rent under this Lease if no new Monthly Base Rent is
stated in Lessor's consent. Any holding over without Lessor's consent will be at
double the Monthly Rent under this Lease. The month-to-month occupancy may be
terminated by Lessor or Tenant on the last day of any month by at least 30
days' prior written notice to the other.

29.  Security Deposit.

Tenant deposits $9,276.00 with Lessor as a security deposit. Lessor may
commingle the security deposit with other funds but will refund this amount to
Tenant without interest on termination of this Lease, less any amounts
necessary in Lessor's reasonable opinion to pay the cost of repair or
restoration of the Premises to the condition required under this Lease or to
cure any defaults of Tenant under this Lease.

30.  Brokers.

Lessor and Tenant represent and warrant one to another that except for Joseph
Antonucci with Landmark Partners, neither of them has employed or otherwise
used any broker or agent in relation to this Lease. Lessor will indemnify and
hold Tenant harmless, and Tenant will indemnify and hold Lessor harmless, from
and against any claims for brokerage or other commissionsor fees arising out of
any breach of the foregoing representation and warranty by the respective 
indemnitors.

31.  Notices.

Any notice under this Lease will be in writing, and will be sent by prepaid
certified mail, or by telegram confirmed by certified mail, addressed to Tenant
at the Premises and to Lessor at 1550 Utica Avenue South, Suite 120, St. Louis
Park, Minnesota 55416, or to such other address as is designated in a notice
given under this Section. A notice will be deemed given on the date mailed.
Lessor's statements of Costs and other routine mailings to tenants need not be
sent by certified mail.

32.  Governing Law.

Tis Lease will be construed under and governed by the laws of Minnesota. If any
provision of this Lease is illegal or unenforceable, it will be severable and
all other provisions will remain in force as though the severable provision had
never been included.

33.  Entire Agreement.

This Lease contains the entire agreement between Lessor and Tenant regarding the
Premises. Tenant agrees that it has not relied on any statement, representation
or warranty of any person except as set out in this Lease. This Lease may be
modified only by an agreement in writing signed by Lessor and Tenant. No
surrender of the Premises, or of the remainder of the Term, will be valid unless
accepted by Lessor in writing.

34.  Successors and Assigns.

All provisions of this Lease will be binding on and for the benefit of the
successors and assigns of Lessor and Tenant, except that no person or entity
holding under or through Tenant in violation of any provision of this Lease
will have any right or interest in this Lease or the Premises.



<PAGE>   12
Lessor and Tenant have executed this Lease to be effective as of the date
stated in the first paragraph of this Lease.

                Lessor:

                MEPC AMERICAN PROPERTIES INC.

                By: /s/ Peter ?????
                    ----------------------

                Its: Senior Vice President

                And

                By: /s/ ????? ?????
                    ----------------------

                Its: Vice President


                TENANT: RINGER CORPORATION
        
                By: /s/ Mark Eisenschenk
                    -----------------------
                    Mark Eisenschenk

                Its: Chief Financial Officer