<PAGE>   1

                                                                  EXHIBIT 10.38

                            CHANGE IN TERMS AGREEMENT


<TABLE>
<CAPTION>
 PRINCIPAL     LOAN DATE     MATURITY     LOAN NO.        CALL      COLLATERAL      ACCOUNT       OFFICER      INITIALS
<S>            <C>          <C>           <C>             <C>       <C>            <C>            <C>          <C>
$10,000,000                 12-30-1998     004615                                  1735058640       B85
</TABLE>

REFERENCES IN THE SHADED AREA ARE FOR LENDERS USE ONLY AND DO NOT LIMIT THE
APPLICABILITY OF THIS DOCUMENT TO ANY PARTICULAR LOAN OR ITEM.

<TABLE>
<S>                                             <C>
Borrower:    Transcrypt International, Inc.      Lender:  U.S. Bank National Association
             4800 NW 1st Street                          Lincoln Main
             Lincoln, NE  68521                          233 South 13th Street
                                                         Lincoln, NE  68508
</TABLE>
--------------------------------------------------------------------------------

Principal amount:  $10,000,000                  Date of Agreement:  May 21, 1998

DESCRIPTION OF EXISTING INDEBTEDNESS. Revolving Promissory Note dated December
31, 1997, in the original amount of $10,000,000.00.

DESCRIPTION OF COLLATERAL.. All inventory, chattel paper, accounts, equipment
and general intangibles and a certificate of deposit purchased from Lender in
the principal amount of $10,000,000.00 and in any renewals thereof.

DESCRIPTION OF CHANGE IN TERMS. The interest rate is changed to 1.250% above the
interest rate on the certificate of deposit pledged as security for the Loan.
Borrower shall purchase from Lender, grant a security interest in and deliver
possession of certificates of deposit in the aggregate amount of $10,000,000.00
to Lender. Lender waives the requirements of any audited year-end financial
statement and monthly borrowing base certificates until June 30, 1998. All other
terms and conditions shall remain the same.

PROMISE TO PAY. Transcrypt International, Inc. ("Borrower") promises to pay to
U.S. Bank National Association ("Lender"), or order, in lawful money of the
United States of America, the principal amount of Ten Million & 00/100 Dollars
($10,000,000.00) or so much as may be outstanding, together with interest on the
unpaid outstanding principal balance of each advance. Interest shall be
calculated from the date of each advance until repayment of each advance.

PAYMENT. Borrower will pay this loan in one payment of all outstanding principal
plus all accrued unpaid interest on December 30, 1998. In addition, Borrower
will pay regular monthly payments of accrued unpaid interest beginning May 31,
1998, and all subsequent interest payments are due on the last day of each month
after that. Th annual interest rate for this Agreement is computed on a 365/360
basis; that is, by applying the ratio of the annual interest rate over a year of
360 days, multiplied by the outstanding principal balance, multiplied by the
actual number of days the principal balance is outstanding. Borrower will pay
Lender at Lender's address shown above or at such other place as Lender may
designate in writing. Unless otherwise agreed or required by applicable law,
payments will be applied first to accrued unpaid interest, then to principal,
and any remaining amount to any unpaid collection costs and late charges.

VARIABLE INTEREST RATE. The interest rate on this Agreement is subject to change
from time to time based on changes in an independent index which is the Interest
Rate on certain Time Certificates of Deposit issued by Lender (the "Index"). The
Index is not necessarily the lowest rate charged by Lender on its loans. If the
Index becomes unavailable during the term of this loan, Lender may designate a
substitute index after notice to Borrower. Lender will tell Borrower the current
Index rate upon Borrower's request. Borrower understands that Lender may make
loans based on other rates as well. The interest rate change will not occur more
often than each 90 days. The Index currently is 5.530% per annum. The interest
rate to be applied to the unpaid principal balance of this Agreement will be at
a rate of 1.250 percentage points over the Index, resulting in an initial rate
of 6.780% per annum. NOTICE: Under no circumstances will the interest rate on
this Note be more than the maximum rate allowed by applicable law.

PREPAYMENT. Borrower may pay all or a portion of the amount owed earlier than it
is due. Early payments will not, unless agreed to by Lender in writing, relieve
Borrower of Borrower's obligation to continue to make payments of accrued unpaid
interest. Rather, they will reduce the principal balance due.

DEFAULT. Borrower will be in default if any of the following happens: (a)
Borrower fails to make any payment when due. (b) Borrower breaks any promise
Borrower has made to Lender, or Borrower fails to comply with or to perform when
due any other term, obligation, covenant, or condition contained in this
Agreement or any agreement related to this Agreement, or in any other agreement
or loan Borrower has with Lender. (c) Any representation or statement made or
furnished to Lender by Borrower or on Borrower's behalf is false or misleading
in any material respect either now or at the time made or furnished. (d)
Borrower becomes insolvent, a receiver is appointed for any part of Borrower's
property, Borrower makes an assignment for the benefit of creditors, or any
proceeding is commenced either by Borrower or against Borrower under any
bankruptcy or insolvency laws. (e) Any creditor tries to take any of Borrower's
property on or in which Lender has a lien or security interest. This includes a
garnishment of any of Borrower's accounts with Lender. (f) Any guarantor dies or
any of the other events described in this default section occurs with respect to
any guarantor of this Agreement. (g) A material adverse change occurs in
Borrower's financial condition, or Lender believes the prospect of payment or
performance of the Indebtedness is impaired. (h) Lender in good faith deems
itself insecure.

If any default, other than a default in payment is curable and if Borrower has
not been given a notice of a breach of the same provision of this Agreement
within the preceding twelve (12) months, it may be cured ( and no event of
default will have occurred) if Borrower, after receiving written notice from
Lender demanding cure of such default: (a) cures the default within fifteen (15)
days; or (b) the cure requires more than fifteen (15) days, immediately
initiates steps which Lender deems in Lender's sole discretion to be sufficient
to cure the default and thereafter continues and completes all reasonable and
necessary steps sufficient to produce compliance as soon as reasonably
practical.

LENDER'S RIGHTS. Upon default, Lender may declare the entire unpaid principal
balance on this Agreement and all accrued unpaid interest immediately due,
without notice, and then Borrower will pay that amount. Upon default, including
failure to pay upon final maturity, Lender, at its option, may also, if
permitted under applicable law, increase the variable interest rate on this
Agreement to 4.250 percentage points over the Index. The interest rate will not
exceed the maximum rate permitted by applicable law. Lender may hire or pay
someone else to help collect this Agreement if Borrower does not pay. Borrower
also will pay Lender that amount. This includes, subject to any limits under
applicable law, Lender's attorney's fees and Lender's legal expenses, whether or
not there is a lawsuit, including attorneys' fees and legal expenses for
bankruptcy proceedings (including efforts to modify or vacate any automatic stay
or injunction), appeals, and any anticipated post-judgment collection services.
If not prohibited by applicable law, Borrower also will pay any court costs, in
addition to all other sums provided by law. This Agreement has been delivered to
Lender and accepted by Lender in the State of Nebraska. If there is a lawsuit,
Borrower agrees upon Lender's request to submit to the jurisdiction of the
courts of Lancaster County, the State of Nebraska. This Agreement shall be
governed by and construed in accordance with the laws of the State of Nebraska.

RIGHT OF SETOFF. Borrower grants to Lender a contractual security interest in,
and hereby assigns, conveys, delivers, pledges, and transfers to Lender all
Borrower's right, title and interest in and to, Borrower's accounts with Lender
(whether checking, savings, or some other account), including without limitation
all accounts held jointly with someone else and all accounts Borrower may open
in the future, excluding however all IRA and Keogh accounts, and all trust
accounts for which the grant of a security interest would be prohibited by law.
Borrower authorizes lender, to the extent permitted by applicable law, to charge
or setoff all sums owing on this Agreement against any and all such accounts.

LINE OF CREDIT. This Agreement evidences a revolving line of credit. Advances
under this Agreement may be requested orally by Borrower or by an authorized
person. Lender may, but need not, require that all oral requests be confirmed in
writing. All communications, instructions, or directions by telephone or
otherwise to Lender are to be directed to Lender's office shown above. The
following party or parties are authorized to request advances under the line of
credit until Lender receives from Borrower at Lender's address shown above
written notice of revocation of their authority: John T. Connor, Jeffrey L.
Fuller and Rebecca Schultz. Borrower agrees to be liable for all sums either (a)
advanced in accordance with the instructions of an authorized person or (b)
credited to any of Borrower's accounts with Lender. The unpaid principal balance
owing on this Agreement at any time may be evidenced by endorsements on this
Agreement or by Lender's internal records, including daily computer print-outs.
Lender will have not obligation to advance funds under this Agreement if: (a)
Borrower or any guarantor is in default under the terms of this Agreement or any
agreement that Borrower or any guarantor has with Lender, including any
agreement made in connection with the signing of this Agreement; (b) Borrower or
any guarantor ceases doing business or is insolvent; (c) any guarantor seeks,
claims or otherwise attempts to limit, modify or revoke such guarantor's
guarantee of this Agreement or any other loan with Lender; (d) Borrower has


                                        1


<PAGE>   2
applied funds provided pursuant to this Agreement for purposes other than those
authorized by Lender; or (e) Lender in good faith deems itself insecure under
this Agreement or any other agreement between Lender and Borrower.

CONTINUING VALIDITY. Except as expressly changed by this Agreement, the terms of
the original obligation or obligations, including all agreements evidenced or
securing the obligation(s), remain unchanged and in full force and effect.
Consent by Lender to this Agreement does not waive Lender's right to strict
performance of the obligation(s) as changed, nor obligate Lender to make any
future change in terms. Nothing in this Agreement will constitute a satisfaction
of the obligation(s). It is the intention of Lender to retain as liable parties
all makers and endorsers of the original obligation(s), including accommodation
parties, unless a party is expressly released by Lender in writing. Any maker or
endorser, including accommodation makers, will not be released by virtue of this
Agreement. If any person who signed the original obligation does not sign this
Agreement below, then all persons signing below acknowledge that this Agreement
is given conditionally, based on the representation to Lender that the
non-signing party consents to the changes and provisions of this Agreement or
otherwise will not be released by it. This waiver applies not only to any
initial extension, modification or release, but also to all such subsequent
actions.

BORROWING BASE CERTIFICATE. Borrower shall deliver a Borrower Base Certificate
to Lender within 30 days after each month end in the form attached hereto as
Exhibit "A" and incorporated herein by this reference. Advances on the Loan
shall be limited to the amounts provided in the current Borrowing Base
Certificate up to a maximum outstanding at any time of no more than $10,000,000.

MISCELLANEOUS PROVISIONS. Lender may delay or forgo enforcing any of its rights
or remedies under this Agreement without losing them. Borrower and any other
person who signs, guarantees or endorses this Agreement, to the extent allowed
by law, waive presentment, demand for payment, protest and notice of dishonor.
Upon any change in the terms of this Agreement, and unless otherwise expressly
stated in writing, no party who signs this Agreement, whether as maker,
guarantor, accommodation maker or endorser, shall be released from liability.
All such parties agree that Lender may renew or extend (repeatedly and for any
length of time) this loan, or release any party or guarantor or collateral; or
impair, fail to realize upon or perfect Lender's security interest in the
collateral; and take any other action deemed necessary by Lender without the
consent of or notice to anyone. All such parties also agree that Lender may
modify this loan without the consent of or notice to anyone other than the party
with whom the modification is made.

PRIOR TO SIGNING THIS AGREEMENT, BORROWER READ AND UNDERSTOOD ALL THE PROVISIONS
OF THIS AGREEMENT, INCLUDING THE VARIABLE INTEREST RATE PROVISIONS. BORROWER
AGREES TO THE TERMS OF THE AGREEMENT AND ACKNOWLEDGES RECEIPT OF A COMPLETED
COPY OF THE AGREEMENT.

BORROWER:
Transcrypt International, Inc.


By: /S/ JOHN T. CONNOR
   -------------------------------
      John T. Connor, Chairman


                                        2


<PAGE>   3
05-21-1998                    CHANGE IN TERMS AGREEMENT                   PAGE 2
LOAN NO. 004615                    (CONTINUED)
--------------------------------------------------------------------------------
                                    EXHIBIT A

                         TRANSCRYPT INTERNATIONAL, INC.

                           BORROWING BASE CERTIFICATE

                              PERIOD ______________

To:       Steve Erwin
          U.S. Bank, N.A.
          233 South 13th Street
          Lincoln, NE 68508

Under the provisions of a Security Agreement between Transcrypt International,
Inc. and U.S. Bank, N.A., covering accounts, inventory, equipment and general
intangibles dated December 31, 1997, the following is submitted:


<TABLE>
<S>                                                                                <C>                          <C>
1.      Total Accounts Receivable Per
        Attached Aging (Less inter-company
        and uninsured foreign accounts)                                                                         $______________

2.      Less:  Past  Due Ineligible
        90 Days or Greater                                                         $_______________

3.      Plus:  Insured Foreign Accounts Receivable                                                              $______________

4.      Eligible Accounts Receivable                                                                            $______________
        (Line 1 minus line 2 plus line 3)

5.      Accounts Receivable Advance Rate                                                                                  80%

6.      Accounts Receivable Availability                                                                        $______________
        (Line 4 time line 5)
</TABLE>


<TABLE>
<CAPTION>
                                                       INELIGIBLE
                                                       PURCHASE
                                                       MONEY                                   ADVANCE
INVENTORY AMOUNT                                       SECURITY            ELIGIBLE            RATE
<S>                                                    <C>                 <C>                 <C>              <C>
7.      Raw Materials                                  $                   $                   50%              $______________

8.      Finished Good                                  $                   $                   50%              $______________

9.      Total Available Collateral
        (Line 6 plus lines 7 & 8)                                                                               $______________
</TABLE>

<TABLE>
<S>                                                                                                     <C>            
10.     Deduct Amount Owing U.S. Bank (Not to exceed $10 million)                                       =       $______________

11.     Excess (Deficiency) Collateral (Line 9 minus line 10)                                           =       $______________

12.     Excess (Deficiency) Percentage (Line 11 divided by line 9)                                      =       $______________

13.     Trade Account Payable As of ______________________ TOTAL $ __________                                   ______________%
</TABLE>


I, _________________________, ______________________ of Transcrypt
International, Inc. do hereby certify that the above is a correct and accurate
representation of the collateral assigned to U.S. Bank, N.A., under the existing
Security Agreement(s).



----------------------------------                        -----------------
Authorized Signature                                      Dated


<PAGE>   4
                            NOTICE OF FINAL AGREEMENT


<TABLE>
<S>            <C>          <C>            <C>             <C>       <C>           <C>             <C>          <C>
 PRINCIPAL     LOAN DATE     MATURITY      LOAN NO.        CALL      COLLATERAL      ACCOUNT       OFFICER      INITIALS
$10,000,000                 12-30-1998     004615                                  1735058640       B85
</TABLE>

REFERENCES IN THE SHADED AREA ARE FOR LENDERS USE ONLY AND DO NOT LIMIT THE
APPLICABILITY OF THIS DOCUMENT TO ANY PARTICULAR LOAN OR ITEM.


<TABLE>
<S>                                           <C>
Borrower:   Transcrypt International, Inc.    Lender:  U.S. Bank National Association
            4800 NW 1st Street                         Lincoln Main
            Lincoln, NE  68521                         233 South 13th Street
                                                       Lincoln, NE  68508
</TABLE>


--------------------------------------------------------------------------------


NOTICE - WRITTEN AGREEMENTS. A credit agreement must be in writing to be
enforceable under Nebraska law. To protect you and us from any misunderstandings
or disappointments, any contract, promise, undertaking or offer to forbear
repayment of money or to make any other financial accommodation in connection
with this loan of money or grant or extension of credit, or any amendment of,
cancellation of, waiver of, or substitution for any or all of the terms or
provisions of any instrument or document executed in connection with this loan
of money or grant or extension of credit must be in writing to be effective.

By signing this document each Party represents and agrees that: (a) The written
Loan Agreement represents the final agreement between the Parties, (b) There are
no unwritten oral agreements between the Parties and (c) The written Loan
Agreement may not be contradicted by evidence of any prior, contemporaneous, or
subsequent oral agreements or understandings of the Parties.

As used in this Notice, the following terms have the following meanings:

          LOAN. The term "Loan" means the following described loan: a Variable
          Rate (1.250% over Interest Rate on certain Time Certificates of
          Deposit issued by Lender, making an initial rate of 6.780%),
          Nondisclosable Revolving Line of Credit Loan to a Corporation for
          $10,000,000.00 due on December 30, 1998. This is a secured renewal
          loan.

          PARTIES. The term "Parties" means U.S. Bank National Association and
          any and all entities or individuals who are obligated to repay the
          loan or have pledged property as security for the Loan, including
          without limitation the following:

          BORROWER:                       Transcrypt International, Inc.
          GUARANTOR:                      E.F. Johnson Company

          LOAN AGREEMENT. The term "Loan Agreement" means one or more promises,
          promissory notes, agreements, undertakings, security agreements, deeds
          of trust or other documents, or commitments, or any combination of
          those actions or documents, relating to the Loan, including without
          limitation the following:

                                 NECESSARY FORMS

          Loan Agreement/Negative Pledge  Promissory Note/Change in Terms Agr.
          Commercial Guaranty             Security Agreement
          Assignment of Deposit Account   UCC-1
          Collateral Receipt              Disbursement Request and Authorization
          Notice of Final Agreement

                                 OPTIONAL FORMS

          Amortization Schedule


Each Party who signs below, other than U.S. Bank National Association,
acknowledges, represents, and warrants to U.S. Bank National Association that it
has received, read and understood this Notice of Final Agreement. This Notice is
dated May 21, 1998.

BORROWER:

Transcrypt International, Inc.


By:  /S/ JOHN T. CONNOR
     -------------------------------
         John T. Connor, Chairman

GUARANTOR:


E.F. Johnson Company

By:  /S/ JOHN T. CONNOR
     -------------------------------

LENDER:
U.S. Bank National Association


By:  /S/ Steve Erwin
     -------------------------------
      Authorized Officer


<PAGE>   5
                                 PROMISSORY NOTE


<TABLE>
<CAPTION>
 PRINCIPAL      LOAN DATE     MATURITY     LOAN NO.        CALL      COLLATERAL      ACCOUNT       OFFICER      INITIALS
<S>            <C>           <C>           <C>             <C>       <C>            <C>            <C>          <C>
$10,000,000    12-31-1997    12-30-1998     004615                                  1735058640      GSB06
</TABLE>


REFERENCES IN THE SHADED AREA ARE FOR LENDERS USE ONLY AND DO NOT LIMIT THE
APPLICABILITY OF THIS DOCUMENT TO ANY PARTICULAR LOAN OR ITEM.


<TABLE>
<S>                                             <C>
Borrower:     Transcrypt International, Inc.    Lender:   U.S. Bank National Association
              4800 NW 1st Street                          Lincoln Main - Commercial
              Lincoln, NE  68521-9918                     233 South 13th Street
                                                          Lincoln, NE  68508
</TABLE>

--------------------------------------------------------------------------------
<TABLE>
<S>                                     <C>                       <C>
Principal Amount: $10,000,000           Initial Rate: 6.780%      Date of Note:  May 21, 1998
</TABLE>

PROMISE TO PAY. Transcrypt International, Inc. ("Borrower") promises to pay to
U.S. Bank National Association ("Lender"), or order, in lawful money of the
United States of America, the principal amount of Ten Million & 00/100 Dollars
($10,000,000) or so much as may be outstanding, together with interest on the
unpaid outstanding principal balance of each advance. Interest shall be
calculated from the date of each advance until repayment of each advance. This
note is extended, delivered and accepted not in payment, but for the purpose of
amending the Promissory Note from Borrower dated December 31, 1997. This Note is
not intended to be and shall not constitute a novation of the indebtedness
evidenced by said Promissory Note.

PAYMENT. Borrower will pay this loan in one payment of all outstanding principal
plus all accrued unpaid interest on December 30, 1998. In addition, Borrower
will pay regular monthly payments of accrued unpaid interest beginning January
31, 1998, and all subsequent interest payments are due on the last day of each
month after that. The annual interest rate for this Note is computed on a
365/360 basis; that is, by applying the ratio of the annual interest rate over a
year of 360 days, multiplied by the outstanding principal balance, multiplied by
the actual number of days the principal balance is outstanding. Borrower will
pay Lender at Lender's address shown above or at such other place as Lender may
designate in writing. Unless otherwise agreed or required by applicable law,
payments will be applied first to accrued unpaid interest, then to principal,
and any remaining amount to any unpaid collection costs and late charges.

VARIABLE INTEREST RATE. The interest rate on this Note is subject to change from
time to time based on changes in an independent index which is the Interest Rate
on certain Time Certificates of Deposit pledged as security for this Note, and
any renewals thereof (the "Index"). The Index is not necessarily the lowest rate
charged by Lender on its loans. If the Index becomes unavailable during the term
of this loan, Lender may designate a substitute index after notice to Borrower.
Lender will tell Borrower the current Index rate upon Borrower's request.
Borrower understands that Lender may make loans based on other rates as well.
The interest rate change will not occur more often than each 90 days. The Index
currently is 5.530% per annum. The interest rate to be applied to the unpaid
principal balance of this Note will be at a rate of 1.250 percentage points
above the Index, resulting in an initial rate of 6.780% per annum. NOTICE: Under
no circumstances will the interest rate on this Note be more than the maximum
rate allowed by applicable law.

PREPAYMENT. Borrower may pay all or a portion of the amount owed earlier than it
is due without penalty. Early payments will not, unless agreed to by Lender in
writing, relieve Borrower of Borrower's obligation to continue to make payments
of accrued unpaid interest. Rather, they will reduce the principal balance due.

DEFAULT. Borrower will be in default if any of the following happens: (a)
Borrower fails to make any payment when due, (b) Borrower fails to comply with
or to perform when due any other term, obligations, covenant, or condition
contained in this Note or any agreement related to this Note, or in any other
agreement or loan Borrower has with Lender. (c) Any representation or statement
made or furnished to Lender by Borrower or on Borrower's behalf is false or
misleading in any material respect either now or at the time made or furnished.
(d) Borrower becomes insolvent, a receiver is appointed for any part of
Borrower's property, Borrower makes an assignment for the benefit of creditors,
or any proceeding is commenced either by Borrower or against Borrower under any
bankruptcy or insolvency laws. (e) Any creditor tries to take any of Borrower's
property on or in which Lender has a lien or security interest. This includes a
garnishment of any of Borrower's accounts with Lender. (f) Any of the other
events described in this default section occurs with respect to any guarantor of
this Note. (g) A material adverse change occurs in Borrower's financial
condition, or Lender believes the prospect of payment or performance of the
Indebtedness is impaired.

If any default, other than a default in payment which is subject to a five (5)
day cure period, is curable and if Borrower has not been given a notice of a
breach of the same provision of this Note within the preceding twelve (12)
months, it may be cured (and no event of default will have occurred if Borrower,
after receiving written notice from Lender demanding cure of such default: (a)
cures the default within twenty (20) days; or (b) if the cure required more
than twenty (20) days, immediately initiates steps which Lender deems in
Lender's sole discretion to be sufficient to cure the default and thereafter
continues and completes all reasonable and necessary steps sufficient to produce
compliance as soon as reasonably practical.

LENDER'S RIGHTS. Upon default, Lender may declare the entire unpaid principal
balance on this Note and all accrued unpaid interest immediately due, without
notice, and then Borrower will pay that amount. Upon default, including failure
to pay upon final maturity. Lender, at its option, may also, if permitted under
applicable law, increase the variable interest rate on this Note to 4.250
percentage points over the Index. The interest rate will not exceed the maximum
rate permitted by applicable law. Lender may hire or pay someone else to help
collect this Note if Borrower does not pay. Borrower also will pay Lender that
amount. This includes, subject to any limits under applicable law, Lender's
attorneys's fees and Lender's legal expenses whether or not there is a lawsuit,
including attorneys' fees and legal expenses for bankruptcy proceedings
(including efforts to modify or vacate any automatic stay or injunction),
appeals, and any anticipated post-judgment collection services. If not
prohibited by applicable law, Borrower also will pay any court costs, in
addition to all other sums provided by law. This Note has been delivered to
Lender and accepted by Lender in the State of Nebraska. If there is a lawsuit,
Borrower agrees upon Lender's request to submit to the jurisdiction of the
courts of Lancaster County, the State of Nebraska. This Note shall be governed
by and construed in accordance with the laws of the State of Nebraska.

RIGHT OF SETOFF. Borrower grants to Lender a contractual possessory security
interest in, and hereby assigns, conveys, delivers, pledges, and transfers to
Lender all Borrower's right, title and interest in and to. Borrower's accounts
with Lender (whether checking, savings, or some other account), excluding
however all IRA and Keogh accounts, and all trust accounts for which the grant
of a security interest would be prohibited by law. Borrower authorizes Lender,
to the extent permitted by applicable law, to charge or setoff all sums owing on
this Note against any and all such accounts.

COLLATERAL. This note is secured by Financing Statement and Security Agreement;
and Lender's possession of Time Certificates of Deposit from Borrower in the
principal amount of $10,000,000.

LINE OF CREDIT. This Note evidences a revolving line of credit. Advances under
this Note may be requested orally by Borrower or as provided in this paragraph.
Lender may, but need not, require that all oral requests be confirmed in
writing. All communications, instructions, or directions by telephone or
otherwise to Lender are to be directed to Lender's office shown above. The
following party or parties are authorized as provided in this paragraph to
request advances under the line of credit until Lender receives from Borrower at
Lender's address shown above written notice of revocation of their authority;
John T. Connor, Jeffery L. Fuller and Rebecca Schultz. Borrower agrees to be
liable for all sums either: (a) advanced in accordance with the instructions of
an authorized person or (b) credited to any of Borrower's accounts with Lender.
The unpaid principal balance owing on this Note at any time may be evidenced by
endorsements on this Note or by Lender's internal records, including daily
computer print-outs. Lender will have no obligation to advance funds under this
Note if: (a) Borrower or any guarantor is in default under the terms of this
Note or any agreement that Borrower or any guarantor has with Lender, including
any agreement made in connection with the signing of this Note; (b) Borrower or
any guarantor ceases doing business or is insolvent; (c) any guaranty seeks,
claims or otherwise attempts to limit, modify or revoke such guarantor's
guarantee of this Note or any other loan with Lender; (d) Borrower has applied
funds provided pursuant to this Note for purposes other than those authorized by
Lender, which are deemed to include Borrower's general corporate operating
needs.


PURPOSE OF LOAN.  General operating needs of the corporation.


                                        1


<PAGE>   6
12-31-1997                        PROMISSORY NOTE                         Page 2
Loan No. 004615                     (Continued)
--------------------------------------------------------------------------------

GENERAL PROVISIONS. Lender may delay or forgo enforcing any of its rights or
remedies under this Note without losing them. Borrower and any other person who
signs, guarantees or endorses this note, to the extent allowed by law, waive
presentment , demand for payment, protest and notice of dishonor. Upon any
change in the terms of this Note, and unless otherwise expressly stated in
writing, no party who signs this Note, whether as maker guarantor, accommodation
maker or endorser, shall be released from liability. All such parties agree that
Lender may renew or extend (repeatedly and for any length of time) this loan, or
release any party or guarantor or collateral; or impair, fail to realize upon or
perfect Lender's security interest in the collateral; and take any other action
deemed necessary by Lender without the consent of or notice to anyone. All such
parties also agree that Lender may modify this loan without the consent of or
notice to anyone other than the party with whom the modification is made.

PRIOR TO SIGNING THIS NOTE, BORROWER READ AND UNDERSTOOD ALL THE PROVISIONS OF
THIS NOTE, INCLUDING THE VARIABLE INTEREST RATE PROVISIONS. BORROWER AGREES TO
THE TERMS OF THE NOTE AND ACKNOWLEDGES RECEIPT OF A COMPLETED COPY OF THE NOTE.

BORROWER:
Transcrypt International, Inc.


By: /S/ JOHN T. CONNOR
    -------------------------------
      John T. Connor, Chairman


                                        2


<PAGE>   7

                          COMMERCIAL SECURITY AGREEMENT


<TABLE>
<CAPTION>
   PRINCIPAL      LOAN DATE     MATURITY      LOAN NO.    CALL     COLLATERAL       ACCOUNT         OFFICER      INITIALS
<S>               <C>          <C>            <C>         <C>      <C>             <C>              <C>          <C>
$10,000,000.00                 12-30-1998      004615                              1735058640         B85
</TABLE>


REFERENCES IN THE SHADED AREA ARE FOR LENDER'S USE ONLY AND DO NOT LIMIT THE
APPLICABILITY OF THIS DOCUMENT TO ANY PARTICULAR LOAN OR ITEM.

<TABLE>
<S>                                          <C>
Borrower: Transcrypt International, Inc.     Lender: U.S. Bank National Association
          4800 NW 1st Street                         Lincoln Main
          Lincoln, NE  68521                         233 South 13th Street
                                                     Lincoln, NE 68508
</TABLE>

--------------------------------------------------------------------------------

THIS COMMERCIAL SECURITY AGREEMENT is entered into between Transcrypt
International, Inc. (referred to below as "Grantor"); and U.S. Bank National
Association (referred to below as "Lender"). For valuable consideration, Grantor
grants to Lender a security interest in the Collateral to secure the
indebtedness and agrees that Lender shall have the rights stated in this
Agreement with respect to the Collateral, in addition to all other rights which
Lender may have by law.

DEFINITIONS. The following words shall have the following meanings when used in
this Agreement. Terms not otherwise defined in this Agreement shall have the
meanings attributed to such terms in the Uniform Commercial Code. All references
to dollar amounts shall mean amounts in lawful money of the United States of
America.

      AGREEMENT. The word "Agreement" means this Commercial Security Agreement,
      as this Commercial Security Agreement may be amended or modified from time
      to time, together with all exhibits and schedules attached to this
      Commercial Security Agreement from time to time.

      COLLATERAL. The word "Collateral" means the following described property
      of Grantor, whether now owned or hereafter acquired, whether now existing
      or hereafter arising, and wherever located:

           All inventory, chattel paper, accounts, equipment and general
      intangibles and Time Certificates of Deposit purchased from Lender in the
      aggregate principal amount of $10,000,000 and in any renewals thereof. In
      addition, the word "Collateral" includes all the following, whether now
      owned or hereafter acquired, whether now existing or hereafter arising,
      and wherever located:

           (a) All attachments, accessions, accessories, tools, parts, supplies,
           increases, and additions to and all replacements of and substitutions
           for any property described above.

           (b) All products and produce of any of the property described in this
           Collateral section.

           (c) All accounts, general intangibles, instruments, rents, monies,
           payments, and all other rights, arising out of a sale, lease, or
           other disposition of any of the property described in this Collateral
           section.

           (d) All proceeds (including insurance proceeds) from the sale,
           destruction, loss, or other disposition of any of the property
           described in this Collateral section.

           (e) All records and data relating to any of the property described in
           this Collateral section, whether in the form of a writing,
           photograph, microfilm, microfiche, or electronic media, together with
           all of Grantor's right, title, and interest in and to all computer
           software required to utilize, create, maintain, and process any such
           records or data on electronic media.

      EVENT OF DEFAULT. The words "Event of Default" mean and include without
      limitation any of the Events of Default set forth below in the section
      titled "Events of Default."

      GRANTOR. The word "Grantor" means Transcrypt International, Inc., its
      successors and assigns.

      GUARANTOR. The word "Guarantor" means and includes without limitation each
      and all of the guarantors, sureties, and accommodation parties in
      connection with the indebtedness.

      INDEBTEDNESS. The word "Indebtedness" means the indebtedness evidenced by
      the Note, including all principal and interest, together with all other
      indebtedness and costs and expenses for which Grantor is responsible under
      this Agreement or under any of the Related Documents.

      LENDER. The word "Lender" means U.S. Bank National Association, its
      successors and assigns.

      NOTE. The word "Note" means the Change in Terms Agreement between Borrower
      and Lender dated May 21, 1998, which modifies the following described
      existing indebtedness: Revolving Promissory Note dated December 31, 1997,
      in the original amount of $10,000,000.00.

      RELATED DOCUMENTS. The words "Related Documents" mean and include without
      limitation all promissory notes, credit agreements, loan agreements,
      environmental agreements, guaranties, security agreements, mortgages,
      deeds of trust, and all other instruments, agreements and documents,
      whether now or hereafter existing, executed in connection with the
      Indebtedness.

RIGHT OF SETOFF. Grantor hereby grants Lender a contractual security interest in
and hereby assigns, conveys, delivers, pledges, and transfers all of Grantor's
right, title and interest in and to Grantor's accounts with Lender (whether
checking, savings, or some other account), including all accounts held jointly
with someone else and all accounts Grantor may open in the future, excluding,
however, all IRA and Keogh accounts, and all trust accounts for which the grant
of a security interest would be prohibited by law. Grantor authorizes Lender, to
the extent permitted by applicable law, to charge or setoff all Indebtedness
against any and all such accounts.

OBLIGATIONS OF GRANTOR.  Grantor warrants and covenants to Lender as follows:

      PERFECTION OF SECURITY INTEREST. Grantor agrees to execute such financing
      statements and to take whatever other actions are requested by Lender to
      perfect and continue Lender's security interest in the Collateral. Upon
      request of Lender, Grantor will deliver to Lender any and all of the
      documents evidencing or constituting the Collateral, and Grantor will note
      Lender's interest upon any and all chattel paper if not delivered to
      Lender for possession by Lender. Grantor hereby appoints Lender as its
      irrevocable attorney-in-fact for the purpose of executing any documents
      necessary to perfect or to continue the security interest granted in this
      Agreement. Lender may at any time, and without further authorization from
      Grantor, file a carbon, photographic or other reproduction of any
      financing statement or of this Agreement for use as a financing statement.
      Grantor will reimburse Lender for all expenses for the perfection and the
      continuation of the perfection of Lender's security interest in the
      Collateral. Grantor promptly will notify Lender before any change in
      Grantor's name including any change to the assumed business names of
      Grantor. This is a continuing Security Agreement and will continue in
      effect even though all or any part of the Indebtedness is paid in full and
      even though for a period of time Grantor may not be indebted to Lender.

      NO VIOLATION. The execution and delivery of this Agreement will not
      violate any law or agreement governing Grantor or to which Grantor is a
      party, and its certificate or articles of incorporation and bylaws do not
      prohibit any term or condition of this Agreement.

      ENFORCEABILITY OF COLLATERAL. To the extent the Collateral consists of
      accounts, chattel paper, or general intangibles, the Collateral is
      enforceable in accordance with its terms, is genuine, and complies with
      applicable laws concerning form, content and manner of preparation and
      execution, and all persons appearing to be obligated on the Collateral
      have authority and capacity to contract and are in fact obligated as they
      appear to be on the Collateral. At the time any account becomes subject to
      a security interest in favor of Lender, the account shall be a good and
      valid account representing an undisputed, bona fide indebtedness incurred
      by the account debtor, for merchandise held subject to delivery
      instructions or theretofore shipped or delivered pursuant to a contract of
      sale, or for services theretofore performed by Grantor with or for the
      account debtor; there shall be no setoffs or counterclaims against any
      such account; and no agreement under which any deductions or discounts may
      be claimed shall have been made with the account debtor except those
      disclosed to Lender in writing.

      LOCATION OF THE COLLATERAL. Grantor, upon request of Lender, will deliver
      to Lender in form satisfactory to Lender a schedule of real properties and
      Collateral locations relating to Grantor's operations, including without
      limitation the following: (a) all real property owned or being purchased
      by Grantor; (b) all real property being rented or leased by Grantor; (c)
      all storage facilities owned, rented, leased, or being used by Grantor;
      and (d) all other properties where Collateral is or may be located. Except
      in the ordinary course of its business, Grantor shall not remove the
      Collateral from its existing locations without the prior written consent
      of Lender.

      REMOVAL OF COLLATERAL. Grantor shall keep the Collateral (or to the extent
      the Collateral consists of intangible property such as accounts, the
      records concerning the Collateral) at Grantor's address shown above, or at
      such other locations as are acceptable to Lender. Except in the ordinary
      course of its business, including the sales of inventory, Grantor shall
      not remove the Collateral from its existing locations without the prior
      written consent of Lender. To the extent that the Collateral consists of
      vehicles, or other titled property, Grantor shall not take or permit any
      action which would require application for certificates of title for the
      vehicles outside the State of Nebraska, without the prior written consent
      of Lender.

      TRANSACTIONS INVOLVING COLLATERAL. Except for inventory sold or accounts
      collected in the ordinary course of Grantor's business, Grantor shall not
      sell, offer to sell, or otherwise transfer or dispose of the Collateral.
      While Grantor is not in default under this Agreement, Grantor may sell
      inventory, but only in the ordinary course of its business and only to
      buyers who qualify as a buyer in the ordinary course of business. A sale
      in the ordinary course of Grantor's business does not include a


<PAGE>   8
05-21-1998                  COMMERCIAL SECURITY AGREEMENT                 Page 2
Loan No. 004615                    (Continued)
--------------------------------------------------------------------------------


      transfer in partial or total satisfaction of a debt or any bulk sale.
      Grantor shall not pledge, mortgage, encumber or otherwise permit the
      Collateral to be subject to any lien, security interest, encumbrance, or
      change, other than the security interest provided for in this Agreement,
      without the prior written consent of Lender. This includes security
      interests even if junior in right to the security interests granted under
      this Agreement. Unless waived by Lender, all proceeds from any disposition
      of the Collateral (for whatever reason) shall be held in trust for Lender
      and shall not be commingled with any other funds; provided, however, this
      requirement shall not constitute consent by Lender to any sale or other
      disposition. Upon receipt, Grantor shall immediately deliver any such
      proceeds to Lender.

      TITLE. Grantor represents and warrants to Lender that it holds good and
      marketable title to the Collateral, free and clear of all liens and
      encumbrances except for the lien of this Agreement. No financing statement
      covering any of the Collateral is on file in any public office other than
      those which reflect the security interest created by this Agreement or to
      which Lender has specifically consented. Grantor shall defend Lender's
      rights in the Collateral against the claims and demands of all other
      persons.

      COLLATERAL SCHEDULES AND LOCATIONS. As often as Lender shall require, and
      insofar as the Collateral consists of accounts and general intangibles,
      Grantor shall deliver to Lender schedules of such Collateral, including
      such information as Lender may require, including without limitation names
      and addresses of account debtors and agings of accounts and general
      intangibles. Insofar as the Collateral consists of inventory and
      equipment, Grantor shall deliver to Lender, as often as Lender shall
      require, such lists, descriptions, and designations of such Collateral as
      Lender may require to identify the nature, extent, and location of such
      Collateral. Such information shall be submitted for Grantor and each of
      its subsidiaries or related companies.

      MAINTENANCE AND INSPECTION OF COLLATERAL. Grantor shall maintain all
      tangible Collateral in good condition and repair. Grantor will not commit
      or permit damage to or destruction of the Collateral or any part of the
      Collateral. Lender and its designated representatives and agents shall
      have the right at all reasonable times to examine, inspect and audit the
      Collateral wherever located. Grantor shall immediately notify Lender of
      all cases involving the return, rejection, repossession, loss or damage of
      or to any Collateral; of any request for credit or adjustment or of any
      other dispute arising with respect to the Collateral; and generally of all
      happenings and events affecting the Collateral or the value or the amount
      of the Collateral.

      TAXES, ASSESSMENTS AND LIENS. Grantor will pay when due all taxes,
      assessments and liens, upon the Collateral, its use or operation, upon
      this Agreement, upon any promissory note or notes evidencing the
      Indebtedness, or upon any of the other Related Documents. Grantor may
      withhold any such payment or may elect to contest any lien if Grantor is
      in good faith conducting an appropriate proceeding to contest the
      obligation to pay and so long as Lender's interest in the Collateral is
      not jeopardized in Lender's sole opinion. If the Collateral is subjected
      to a lien which is not discharged within fifteen (15) days, Grantor shall
      deposit with Lender cash, a sufficient corporate surety bond or other
      security satisfactory to Lender in an amount adequate to provide for the
      discharge of the lien plus any interest, costs, attorneys' fees or other
      charges that could accrue as a result of foreclosure or sale of the
      Collateral. In any contest Grantor shall defend itself and Lender and
      shall satisfy any final adverse judgment before enforcement against the
      Collateral. Grantor shall name Lender as an additional obligee under any
      surety bond furnished in the contest proceedings.

      COMPLIANCE WITH GOVERNMENTAL REQUIREMENTS. Grantor shall comply promptly
      with all laws, ordinances, rules and regulations of all governmental
      authorities, now or hereafter in effect, applicable to the ownership,
      production, disposition, or use of the Collateral. Grantor may contest in
      good faith any such law, ordinance or regulation and withhold compliance
      during any proceeding, including appropriate appeals, so long as Lender's
      interest in the Collateral, in Lender's opinion, is not jeopardized.

      HAZARDOUS SUBSTANCES. Grantor represents and warrants that the Collateral
      never has been, and never will be so long as this Agreement remains a lien
      on the Collateral, used for the generation, manufacture, storage,
      transportation, treatment, disposal, release or threatened release of any
      hazardous waste or substance, as those terms are defined in the
      Comprehensive Environmental Response, Compensation, and Liability Act of
      1980, as amended, 42 U.S.C. Section 9601, et seq. ("CERCLA"), the
      Superfund Amendments and Reauthorization Act of 1986, Pub. L. No. 99-499
      ("SARA"), the Hazardous Materials Transportation Act, 49 U.S.C. Section
      1801, et seq., the Resource Conservation and Recovery Act, 42 U.S.C.
      Section 6901, et seq., or other applicable state or Federal laws, rules,
      or regulations adopted pursuant to any of the foregoing. The terms
      "hazardous waste" and "hazardous substance" shall also include, without
      limitation, petroleum and petroleum by-products or any fraction thereof
      and asbestos. The representations and warranties contained herein are
      based on Grantor's due diligence in investigating the Collateral for
      hazardous wastes and substances. Grantor hereby (a) releases and waives
      any future claims against Lender for indemnity or contribution in the
      event Grantor becomes liable for cleanup or other costs under any such
      laws, and (b) agrees to indemnify and hold harmless Lender against any and
      all claims and losses resulting from a breach of this provision of this
      Agreement. This obligation to indemnify shall survive the payment of the
      Indebtedness and the satisfaction of this Agreement.

      MAINTENANCE OF CASUALTY INSURANCE. Grantor shall procure and maintain all
      risks insurance, including without limitation fire, theft and liability
      coverage together with such other insurance as Lender may require with
      respect to the Collateral, in form, amounts, coverages, and basis
      reasonably acceptable to Lender and issued by a company or companies
      reasonably acceptable to Lender. Grantor, upon request of Lender, will
      deliver to Lender from time to time the policies or certificates of
      insurance in form satisfactory to Lender, including stipulations that
      coverages will not be cancelled or diminished without at least ten (10)
      days' prior written notice to Lender and not including any disclaimer of
      the insurer's liability for failure to give such a notice. Each insurance
      policy also shall include an endorsement providing that coverage in favor
      of Lender will not be impaired in any way by any act, omission or default
      of Grantor or any other person. In connection with all policies covering
      assets in which Lender holds or is offered a security interest, Grantor
      will provide Lender with such loss payable or other endorsements as Lender
      may require. If Grantor at any time fails to obtain or maintain any
      insurance as required under this Agreement, Lender may (but shall not be
      obligated to) obtain such insurance as Lender deems appropriate, including
      if it so chooses "single interest insurance," which will cover only
      Lender's interest in the Collateral.

      APPLICATION OF INSURANCE PROCEEDS. Grantor shall promptly notify Lender of
      any loss or damage to the Collateral. Lender may make proof of loss if
      Grantor fails to do so within fifteen (15) days of the casualty. All
      proceeds of any insurance on the Collateral, including accrued proceeds
      thereon, shall be held by Lender as part of the Collateral. If Lender
      consents to repair or replacement of the damaged or destroyed Collateral,
      Lender shall, upon satisfactory proof of expenditure, pay or reimburse
      Grantor from the proceeds for the reasonable cost of repair or
      restoration. If Lender does not consent to repair or replacement of the
      Collateral, Lender shall retain a sufficient amount of the proceeds to pay
      all of the Indebtedness, and shall pay the balance to Grantor. Any
      proceeds which have not been disbursed within six (6) months after their
      receipt and which Grantor has not committed to the repair or restoration
      of the Collateral shall be used to prepay the Indebtedness.

      INSURANCE RESERVES. Lender may require Grantor to maintain with Lender
      reserves for payment of insurance premiums, which reserves shall be
      created by monthly payments from Grantor of a sum estimated by Lender to
      be sufficient to produce, at least fifteen (15) days before the premium
      due date, amounts at least equal to the insurance premiums to be paid. If
      fifteen (15) days before payment is due, the reserve funds are
      insufficient, Grantor shall upon demand pay any deficiency to Lender. The
      reserve funds shall be held by Lender as a general deposit and shall
      constitute a non-interest-bearing account which Lender may satisfy by
      payment of the insurance premiums required to be paid by Grantor as they
      become due. Lender does not hold the reserve funds in trust for Grantor,
      and Lender is not the agent of Grantor for payment of the insurance
      premiums required to be paid by Grantor. The responsibility for the
      payment of premiums shall remain Grantor's sole responsibility.

      INSURANCE REPORTS. Grantor, upon request of Lender, shall furnish to
      Lender reports on each existing policy of insurance showing such
      information as Lender may reasonably request including the following: (a)
      the name of the insurer; (b) the risks insured; (c) the amount of the
      policy; (d) the property insured; (e) the then current value on the basis
      of which insurance has been obtained and the manner of determining that
      value; and (f) the expiration date of the policy. In addition, Grantor
      shall upon request by Lender (however, not more often than annually) have
      an independent appraiser satisfactory to Lender determine, as applicable,
      the cash value or replacement cost of the Collateral.

GRANTOR'S RIGHT TO POSSESSION AND TO COLLECT ACCOUNTS. Until default and except
as otherwise provided below with respect to the accounts, Grantor may have
possession of the tangible personal property and beneficial use of all the
Collateral and may use it in any lawful manner not inconsistent with this
Agreement or the Related Documents, provided that Grantor's right to possession
and beneficial use shall not apply to any Collateral where possession of the
Collateral by Lender is required by law to perfect Lender's security interest in
such Collateral. Until otherwise notified by Lender, Grantor may collect any of
the Collateral consisting of accounts. At any time and even though no Event of
Default exists, Lender may exercise its rights to collect the accounts and to
notify account debtors to make payments directly to Lender for application to
the Indebtedness. If Lender at any time has possession of any Collateral,
whether before or after an Event of Default, Lender shall be deemed to have
exercised reasonable care in the custody and preservation of the Collateral if
Lender takes such action for that purpose as Grantor shall request or as Lender,
in Lender's sole discretion, shall deem appropriate under the circumstances, but
failure to honor any request by Grantor shall not of itself be deemed to be a
failure to exercise reasonable care. Lender shall not be required to take any
steps necessary to preserve any rights in the Collateral against prior parties,
nor to protect, preserve or maintain any security interest given to secure the
Indebtedness.

EXPENDITURES BY LENDER. If not discharged or paid when due, Lender may (but
shall not be obligated to) discharge or pay any amounts required to be
discharged or paid by Grantor under this Agreement, including without limitation
all taxes, liens, security interests, encumbrances, and other claims, at any
time levied or placed on the Collateral. Lender also may (but still not be
obligated to) pay all costs for insuring, maintaining and preserving the
Collateral. All such expenditures incurred or paid by Lender for such purposes
will then bear interest at the rate charged under the Note from the date
incurred or paid by Lender to the date of repayment by Grantor. All such
expenses shall become a part of the Indebtedness and, at Lender's option, will
(a) be payable on demand, (b) be added to the balance of the Note and be
apportioned among and be payable with any installment payments to become due
during either (i) the term of any applicable insurance policy or (ii) the
remaining term of the Note, or (c) be treated as a balloon payment which will be
due and payable at the Note's maturity. This Agreement also will secure payment
of these amounts. Such right shall be in addition to all other rights and
remedies to which Lender may be entitled upon the occurrence of an Event of
Default.


<PAGE>   9
05-21-1998                  COMMERCIAL SECURITY AGREEMENT                 Page 3
Loan No. 004615                    (Continued)
--------------------------------------------------------------------------------


EVENTS OF DEFAULT. Each of the following shall constitute an Event of Default
under this Agreement:

      DEFAULT ON INDEBTEDNESS. Failure of Grantor to make any payment when due
      on the Indebtedness.

      OTHER DEFAULTS. Failure of Grantor to comply with or to perform any other
      term, obligation, covenant or condition contained in this Agreement or in
      any of the Related Documents or in any other agreement between Lender and
      Grantor.

      FALSE STATEMENTS. Any warranty, representation or statement made or
      furnished to Lender by or on behalf of Grantor under this Agreement, the
      Note or the Related Documents is false or misleading in any material
      respect, either now or at the time made or furnished.

      DEFECTIVE COLLATERALIZATION. This Agreement or any of the Related
      Documents ceases to be in full force and effect (including failure of any
      collateral documents to create a valid and perfected security interest or
      lien) at any time and for any reason.

      INSOLVENCY. The dissolution or termination of Grantor's existence as a
      going business, the insolvency of Grantor, the appointment of a receiver
      for any part of Grantor's property, any assignment for the benefit of
      creditors, any type of creditor workout, or the commencement of any
      proceeding under any bankruptcy or insolvency laws by or against Grantor.

      CREDITOR OR FORFEITURE PROCEEDINGS. Commencement of foreclosure or
      forfeiture proceedings, whether by judicial proceeding, self-help,
      repossession or any other method, by any creditor of Grantor or by any
      governmental agency against the Collateral or any other collateral
      securing the Indebtedness. This includes a garnishment of any of Grantor's
      deposit accounts with Lender. However, this Event of Default shall not
      apply if there is a good faith dispute by Grantor as to the validity or
      reasonableness of the claim which is the basis of the creditor or
      forfeiture proceeding and if Grantor gives Lender written notice of the
      creditor or forfeiture proceeding and deposits with Lender monies or a
      surety bond for the creditor or forfeiture proceeding, in an amount
      determined by Lender, in its sole discretion, as being an adequate reserve
      or bond for the dispute.

      EVENTS AFFECTING GUARANTOR. Any of the preceding events occurs with
      respect to any Guarantor of any of the Indebtedness or such Guarantor dies
      or becomes incompetent. Lender, at its option, may, but shall not be
      required to, permit the Guarantor's estate to assume unconditionally the
      obligations arising under the guaranty in a manner satisfactory to Lender,
      and, in doing so, cure the Event of Default.

      ADVERSE CHANGE. A material adverse change occurs in Grantor's financial
      condition, or Lender believes the prospect of payment or performance of
      the Indebtedness is impaired.

      RIGHT TO CURE. If any default, other than a Default on indebtedness, is
      curable and if Grantor has not been given a prior notice of a breach of
      the same provision of this Agreement, it may be cured (and no Event of
      Default will have occurred) if Grantor, after Lender sends written notice
      demanding cure of such default, (a) cures the default within fifteen (15)
      days; or (b), if the cure requires more than fifteen (15) days,
      immediately initiates steps which Lender deems in Lender's sole discretion
      to be sufficient to cure the default and thereafter continues and
      completes all reasonable and necessary steps sufficient to produce
      compliance as soon as reasonably practical.

RIGHTS AND REMEDIES ON DEFAULT. If an Event of Default occurs under this
Agreement, at any time thereafter, Lender shall have all the rights of a secured
party under the Nebraska Uniform Commercial Code. In addition and without
limitation, Lender may exercise any one or more of the following rights and
remedies:

      ACCELERATE INDEBTEDNESS. Lender may declare the entire Indebtedness,
      including any prepayment penalty which Grantor would be required to pay,
      immediately due and payable, without notice.

      ASSEMBLE COLLATERAL. Lender may require Grantor to deliver to Lender all
      or any portion of the Collateral and any and all certificates of title and
      other documents relating to the Collateral. Lender may require Grantor to
      assemble the Collateral and make it available to Lender at a place to be
      designated by Lender. Lender also shall have full power to enter upon the
      property of Grantor to take possession of and remove the Collateral. If
      the Collateral contains other goods not covered by this Agreement at the
      time of repossession, Grantor agrees Lender may take such other goods,
      provided that Lender makes reasonable efforts to return them to Grantor
      after repossession.

      SELL THE COLLATERAL. Lender shall have full power to sell, lease,
      transfer, or otherwise deal with the Collateral or proceeds thereof in its
      own name or that of Grantor. Lender may sell the Collateral at public
      auction or private sale. Unless the Collateral threatens to decline
      speedily in value or is of a type customarily sold on a recognized market,
      Lender will give Grantor reasonable notice of the time and place of any
      public sale, or of the time after which any private sale or any other
      intended disposition of the Collateral is to be made. The requirements of
      reasonable notice shall be met if such notice is given at least ten (10)
      days before the time of the sale or disposition. All expenses relating to
      the disposition of the Collateral, including without limitation the
      expenses of retaking, holding, insuring, preparing for sale and selling
      the Collateral, shall become a part of the Indebtedness secured by this
      Agreement and shall be payable on demand, with interest at the Note rate
      from date of expenditure until repaid.

      APPOINT RECEIVER. To the extent permitted by applicable law, Lender shall
      have the following rights and remedies regarding the appointment of a
      receiver: (a) Lender may have a receiver appointed as a matter of right,
      (b) the receiver may be an employee of Lender and may serve without bond,
      and (c) all fees of the receiver and his or her attorney shall become part
      of the Indebtedness secured by this Agreement and shall be payable on
      demand, with interest at the Note rate from date of expenditure until
      repaid.

      COLLECT REVENUES, APPLY ACCOUNTS. Lender, either itself or through a
      receiver, may collect the payments, rents, income, and revenues from the
      Collateral. Lender may at any time in its discretion transfer any
      Collateral into its own name or that of its nominee and receive the
      payments, rents, income, and revenues therefrom and hold the same as
      security for the Indebtedness or apply it to payment of the Indebtedness
      in such order of preference as Lender may determine. Insofar as the
      Collateral consists of accounts, general intangibles, insurance policies,
      instruments, chattel paper, choses in action, or similar property, Lender
      may demand, collect, receipt for, settle, compromise, adjust, sue for,
      foreclose, or realize on the Collateral as Lender may determine, whether
      or not indebtedness or Collateral is then due. For these purposes, Lender
      may, on behalf of and in the name of Grantor, receive, open and dispose of
      mail addressed to Grantor; change any address to which mail and payments
      are to be sent; and endorse notes, checks, drafts, money orders, documents
      of title, instruments and items pertaining to payment, shipment, or
      storage of any Collateral. To facilitate collection, Lender may notify
      account debtors and obligors on any Collateral to make payments directly
      to Lender.

      OBTAIN DEFICIENCY. If Lender chooses to sell any or all of the Collateral,
      Lender may obtain a judgment against Grantor for any deficiency remaining
      on the Indebtedness due to Lender after application of all amounts
      received from the exercise of the rights provided in this Agreement.
      Grantor shall be liable for a deficiency even if the transaction described
      in this subsection is a sale of accounts or chattel paper.

      OTHER RIGHTS AND REMEDIES. Lender shall have all the rights and remedies
      of a secured creditor under the provisions of the Uniform Commercial Code,
      as may be amended from time to time. In addition, Lender shall have and
      may exercise any or all other rights and remedies it may have available at
      law, in equity, or otherwise.

      CUMULATIVE REMEDIES. All of Lender's rights and remedies, whether
      evidenced by this Agreement or the Related Documents or by any other
      writing, shall be cumulative and may be exercised singularly or
      concurrently. Election by Lender to pursue any remedy shall not exclude
      pursuit of any other remedy, and an election to make expenditures or to
      take action to perform an obligation of Grantor under this Agreement,
      after Grantor's failure to perform, shall not affect Lender's right to
      declare a default and to exercise its remedies.

MISCELLANEOUS PROVISIONS. The following miscellaneous provisions are a part of
this Agreement:

      AMENDMENTS. This Agreement, together with any Related Documents,
      constitutes the entire understanding and agreement of the parties as to
      the matters set forth in this Agreement. No alteration of or amendment to
      this Agreement shall be effective unless given in writing and signed by
      the party or parties sought to be charged or bound by the alteration or
      amendment.

      APPLICABLE LAW. This Agreement has been delivered to Lender and accepted
      by Lender in the State of Nebraska. If there is a lawsuit, Grantor agrees
      upon Lender's request to submit to the jurisdiction of the courts of the
      State of Nebraska. This Agreement shall be governed by and construed in
      accordance with the laws of the State of Nebraska.

      ATTORNEYS' FEES; EXPENSES. Grantor agrees to pay upon demand all of
      Lender's costs and expenses, including attorneys' fees and Lender's legal
      expenses, incurred in connection with the enforcement of this Agreement.
      Lender may pay someone else to help enforce this Agreement, and Grantor
      shall pay the costs and expenses of such enforcement. Costs and expenses
      include Lender's attorneys' fees and legal expenses whether or not there
      is a lawsuit, including attorneys' fees and legal expenses for bankruptcy
      proceedings (and including efforts to modify or vacate any automatic stay
      or injunction), appeals, and any anticipated post-judgment collection
      services. Grantor also shall pay all court costs and such additional fees
      as may be directed by the court.


<PAGE>   10
05-21-1998                  COMMERCIAL SECURITY AGREEMENT                 Page 4
Loan No. 004615                    (Continued)
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      CAPTION HEADINGS. Caption headings in this Agreement are for convenience
      purposes only and are not to be used to interpret or define the provisions
      of this Agreement.

      MULTIPLE PARTIES; CORPORATE AUTHORITY. All obligations of Grantor under
      this Agreement shall be joint and several, and all references to Grantor
      shall mean each and every Grantor. This means that each of the persons
      signing below is responsible for all obligations in this Agreement.

      NOTICES. All notices required to be given under this Agreement shall be
      given in writing, may be sent by telefacsimile (unless otherwise required
      by law), and shall be effective when actually delivered or when deposited
      with a nationally recognized overnight courier or deposited in the United
      States mail, first class, postage prepaid, addressed to the party to whom
      the notice is to be given at the address shown above. Any party may change
      its address for notices under this Agreement by giving formal written
      notice to the other parties, specifying that the purpose of the notice is
      to change the party's address. To the extent permitted by applicable law,
      if there is more than one Grantor, notice to any Grantor will constitute
      notice to all Grantors. For notice purposes, Grantor will keep Lender
      informed at all times of Grantor's current address(es).

      POWER OF ATTORNEY. Grantor hereby appoints Lender as its true and lawful
      attorney-in-fact, irrevocably, with full power of substitution to do the
      following: (a) to demand, collect, receive, receipt for, sue and recover
      all sums of money or other property which may now or hereafter become due,
      owing or payable from the Collateral; (b) to execute, sign and endorse any
      and all claims, instruments, receipts, checks, drafts or warrants issued
      in payment for the Collateral; (c) to settle or compromise any and all
      claims arising under the Collateral, and, in the place and stead of
      Grantor, to execute and deliver its release and settlement for the claim;
      and (d) to file any claim or claims or to take any action or institute or
      take part in any proceedings, either in its own name or in the name of
      Grantor, or otherwise, which in the discretion of Lender may seem to be
      necessary or advisable. This power is given as security for the
      Indebtedness, and the authority hereby conferred is and shall be
      irrevocable and shall remain in full force and effect until renounced by
      Lender.

      SEVERABILITY. If a court of competent jurisdiction finds any provision of
      this Agreement to be invalid or unenforceable as to any person or
      circumstance, such finding shall not render that provision invalid or
      unenforceable as to any other persons or circumstances. If feasible, any
      such offending provision shall be deemed to be modified to be within the
      limits of enforceability or validity; however, if the offending provision
      cannot be so modified, it shall be stricken and all other provisions of
      this Agreement in all other respects shall remain valid and enforceable.

      SUCCESSOR INTERESTS. Subject to the limitations set forth above on
      transfer of the Collateral, this Agreement shall be binding upon and inure
      to the benefit of the parties, their successors and assigns.

      WAVIER. Lender shall not be deemed to have waived any rights under this
      Agreement unless such waiver is given in writing and signed by Lender. No
      delay or omission on the part of Lender in exercising any right shall
      operate as a waiver of such right or any other right. A waiver by Lender
      of a provision of this Agreement shall not prejudice or constitute a
      waiver of Lender's right otherwise to demand strict compliance with that
      provision or any other provision of this Agreement. No prior waiver by
      Lender, nor any course of dealing between Lender and Grantor, shall
      constitute a wavier of any of Lender's rights or of any of Grantor's
      obligations as to any future transactions. Whenever the consent of Lender
      is required under this Agreement, the granting of such consent by Lender
      in any instance shall not constitute continuing consent to subsequent
      instances where such consent is required and in all cases such consent may
      be granted or withheld in the sole discretion of Lender.

GRANTOR ACKNOWLEDGES HAVING READ ALL THE PROVISIONS OF THIS COMMERCIAL SECURITY
AGREEMENT, AND GRANTOR AGREES TO ITS TERMS. THIS AGREEMENT IS DATED MAY 21,
1998.

GRANTOR:

Transcrypt International, Inc.


By:/s/ John T. Connor
   -------------------------------
     John T. Connor, Chairman


LENDER:

U.S. Bank National Association


By:/s/ Steve Erwin
   -------------------------------
     Authorized Officer

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