THIRD ADDENDUM TO LEASE

        This addendum is entered into this 18th day of  September,  2000, by and
between VALLEY AMERICAN INVESTMENT COMPANY,  P.O. Box 186, Midvale,  Utah 84047,
as Landlord; and GENTNER COMMUNICATIONS  CORPORATION, of 1825 West Research Way,
West Valley City, UT 84199, as Tenant.

        Whereas,  both  Tenant  and  Landlord  have  executed  a  uniform  lease
agreement dated the 26th day of February,  1996, a First Addendum to Lease dated
the 31st day of January,  1997, and a Second Addendum to Lease dated the 2nd day
of May,  1997. The size of Tenant's  leased  premises is 40,250 square feet. The
current lease term shall expire on October 31, 2006.

        Whereas,  the purpose of this Third  Addendum is to increase the size of
the leased premises.

        Whereas,  Tenant is desirous of leasing an additional 11,510 square feet
located at 1825 West Research Way, Suite 7 (the "Expansion  Space").  Therefore,
the total size of the leased premises shall be 51,760 square feet.

        The term for this  expansion  space shall commence on September 1, 2000,
and shall run  co-terminously  with the  original  lease,  the First and  Second
Addendums, expiring on October 31, 2006.

        In consideration of this Addendum, Landlord and Tenant agree as follows:

        a.      Tenant shall take space in its current, as is condition.

        b.      Landlord shall deliver possession  of  the  expansion  space  to
                Tenant upon execution of this Addendum.

        c.      Tenant shall pay rent as follows:
<TABLE>
<CAPTION>

=================== ================= ================= ================ =================
       ITEM            09/01/00-          11/01/00-         11/01/02-        11/01/04-
                       10/31/00           10/31/02          10/31/04         10/31/06
------------------- ----------------- ----------------- ---------------- -----------------
<S>                 <C>               <C>               <C>              <C>
Base Rent Per       22,258.00         24,039.00         25,912.00        28,039.00
Lease
------------------- ----------------- ----------------- ---------------- -----------------
1st Addendum        488.60            488.60            488.60           488.60
Amortization
------------------- ----------------- ----------------- ---------------- -----------------
2nd Addendum        1,049.00          1,049.00          1,049.00         1,049.00
Amortization
------------------- ----------------- ----------------- ---------------- -----------------
3rd Addendum        4,550.00          4,550.00          4,914.00         5,307.12
Expansion
------------------- ----------------- ----------------- ---------------- -----------------
CAM Budget          4,775.00          4,775.00          4,775.00         4,775.00
------------------- ----------------- ----------------- ---------------- -----------------
Total Monthly       33,120.60         34,901.60         37,138.60        39,658.72
Payment
=================== ================= ================= ================ =================
</TABLE>

<PAGE>

        d.     Tenant  and  Landlord  agree if the  space  located  at 1825 West
               Research Way, Suite 6 (the "option space") ever becomes available
               during the lease term,  Tenant must,  at  Landlord's  discretion,
               lease this option space.

               1.     Tenant  can  lease  the  "option   space"   consisting  of
                      approximately  7,214  square  feet.  Rent for the  "option
                      space"  shall be at the same rate as the  current  rent on
                      the expansion space at the time Tenant takes possession of
                      the "option space."

               2.     If  Tenant  does  not want the  "option  space"  described
                      above,  Tenant must give up the "front  office"  space and
                      "rear  loading"  space (as shown on the  attached  Exhibit
                      "A") to Landlord so that Landlord may have a  "marketable"
                      Suite #6.  Tenant's  rent and size  shall  then be reduced
                      accordingly.

        Except as  modified  by the  provisions  of this  Addendum,  all  terms,
conditions and provisions of the Lease shall remain  unchanged and in full force
and effect.

        Executed by the parties on the day and year first  written above in Salt
Lake City, Utah.





LANDLORD:                    VALLEY AMERICAN INVESTMENT


                             /s/William C. Roderick
                             ------------------------------------------------
                             William C. Roderick
                             Vice President


TENANT:                      GENTNER COMMUNICATIONS CORPORATION


                             /s/Susie Strohm
                             ------------------------------------------------
                             By: Susie Strohm
                             Its: Chief Financial Officer



<PAGE>




STATE OF UTAH         )
County of Salt Lake   )

        On the  22nd day of  September,  2000,  personally  appeared  before  me
WILLIAM  C.  RODERICK,  the  signer of the  foregoing  lease  addendum  who duly
acknowledged to me that he executed the same.



/s/
----------------------------------------
NOTARY PUBLIC



STATE OF UTAH         )
County of Salt Lake   )

        On the 18th day of September,  2000, personally appeared before me Susie
Strohm,  the signer of the foregoing lease addendum who duly  acknowledged to me
that he/she executed the same.



/s/
----------------------------------------
NOTARY PUBLIC