<PAGE>   1
                                                                     EXHIBIT 1.1

                                   DATUM INC.

   
                              2,452,778 SHARES(1)
    

                                  COMMON STOCK

                             UNDERWRITING AGREEMENT
                             ----------------------
                                                                          , 1997
                                                               -----------

HAMBRECHT & QUIST LLC
OPPENHEIMER & CO., INC.
VAN KASPER & COMPANY
  c/o Hambrecht & Quist LLC
  One Bush Street
  San Francisco, CA 94104

Ladies and Gentlemen:

   
                 Datum Inc., a Delaware corporation (herein called the
Company), proposes to issue and sell 1,000,000 shares of its authorized but
unissued Common Stock, $0.25 par value (herein called the Common Stock), and
the stockholders of the Company named in Schedule II hereto (herein
collectively called the Selling Stockholders) propose to sell an aggregate of
1,452,778 shares of Common Stock of the Company (said 2,452,778 shares of
Common Stock being herein called the Underwritten Stock).  The Company proposes
to grant to the Underwriters (as hereinafter defined) an option to purchase up
to an aggregate of 367,917 additional shares of Common Stock (herein called the
Option Stock and with the Underwritten Stock herein collectively called the
Stock).  The Common Stock is more fully described in the Registration Statement
and the Prospectus hereinafter mentioned.
    

                 The Company and the Selling Stockholders severally hereby
confirm the agreements made with respect to the purchase of the Stock by the
several underwriters, for whom you are acting, named in Schedule I hereto
(herein collectively called the Underwriters, which term shall also include any
underwriter purchasing Stock pursuant to Section 3(b) hereof).  You represent
and warrant that you have been authorized by each of the other Underwriters to
enter into this Agreement on its behalf and to act for it in the manner herein
provided.

   
                 1.       REGISTRATION STATEMENT.  The Company has filed with
the Securities and Exchange Commission (herein called the Commission) a
registration statement on Form S-2 (No. 333-22177), including the related
preliminary prospectus, for the registration under the Securities Act of 1933,
as amended (herein called the Securities Act), of the Stock.  Copies of such
registration statement and of each amendment thereto, if any, including the
related preliminary prospectus (meeting the requirements of Rule 430A of the
rules and
    



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

1  Plus an option to purchase from the Company up to 367,917 additional shares
   to cover over-allotments.
    
<PAGE>   2
regulations of the Commission) heretofore filed by the Company with the
Commission have been delivered to you.

                 The term Registration Statement as used in this agreement
shall mean such registration statement, including all documents incorporated by
reference therein, all exhibits and financial statements, all information
omitted therefrom in reliance upon Rule 430A and contained in the Prospectus
referred to below, in the form in which it became effective, and any
registration statement filed pursuant to Rule 462(b) of the rules and
regulations of the Commission with respect to the Stock (herein called a Rule
462(b) registration statement), and, in the event of any amendment thereto
after the effective date of such registration statement (herein called the
Effective Date), shall also mean (from and after the effectiveness of such
amendment) such registration statement as so amended (including any Rule 462(b)
registration statement).  The term Prospectus as used in this Agreement shall
mean the prospectus, including the documents incorporated by reference therein,
relating to the Stock first filed with the Commission pursuant to Rule 424(b)
and Rule 430A (or if no such filing is required, as included in the
Registration Statement) and, in the event of any supplement or amendment to
such prospectus after the Effective Date, shall also mean (from and after the
filing with the Commission of such supplement or the effectiveness of such
amendment) such prospectus as so supplemented or amended.  The term Preliminary
Prospectus as used in this Agreement shall mean each preliminary prospectus,
including the documents incorporated by reference therein, included in such
registration statement prior to the time it becomes effective.

                 The Registration Statement has been declared effective under
the Securities Act, and no post-effective amendment to the Registration
Statement has been filed as of the date of this Agreement. The Company has
caused to be delivered to you copies of each Preliminary Prospectus and has
consented to the use of such copies for the purposes permitted by the
Securities Act.

    2.       REPRESENTATIONS AND WARRANTIES OF THE COMPANY AND THE SELLING
STOCKHOLDERS.

   
             (a)     The Company hereby represents and warrants to the 
Underwriters and the Selling Stockholders as follows:
    

                     (i)      The Company has been duly incorporated and is 
validly existing as a corporation in good standing under the laws of the State
of Delaware, has full corporate power and authority to own or lease its
properties and conduct its business as described in the Registration Statement
and the Prospectus and as being conducted, and is duly qualified as a foreign
corporation and in good standing in all jurisdictions in which the character of
the property owned or leased or the nature of the business transacted by it
makes qualification necessary (except where the failure to be so qualified would
not have a material adverse effect on the business, properties, condition
(financial or otherwise) or results of operations or prospects of the Company
and its subsidiaries taken as whole (a "Material Adverse Effect")).

                     (ii)     The Company owns all of the shares of capital 
stock of each subsidiary of the Company, and each of the Company's subsidiaries
has been duly 




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incorporated and is validly existing as a corporation in good standing under
the laws of the jurisdiction of its incorporation, has full corporate power and
authority to own or lease its properties and conduct its business as described
in the Registration Statement and the Prospectus and as being conducted, and is
duly qualified as a foreign corporation and in good standing in all
jurisdictions in which the character of the property owned or leased or the
nature of the business transacted by it makes qualification necessary except
where the failure to be so qualified would not have a Material Adverse Effect.

                                  (iii)    Since the respective dates as of
which information is given in the Registration Statement and the Prospectus,
there has not been any materially adverse change in the business, properties,
financial condition or results of operations or prospects of the Company and
its subsidiaries, taken as a whole, whether or not arising from transactions in
the ordinary course of business, other than as set forth in the Registration
Statement and the Prospectus, and since such dates, except in the ordinary
course of business, neither the Company nor any of its subsidiaries has entered
into any material transaction not referred to in the Registration Statement and
the Prospectus.

   
                                  (iv)     The Commission has not issued any
order preventing or suspending the use of any Preliminary Prospectus relating
to the proposed offering of the Stock nor instituted or, to the best knowledge
of the Company, after due inquiry, threatened instituting proceedings for that
purpose. The Registration Statement and the Prospectus comply, and on the
Closing Date (as hereinafter defined) and any later date on which Option Stock
is to be purchased, the Prospectus will comply, in all material respects, with
the provisions of the Securities Act and the Securities Exchange Act of 1934,
as amended (herein called the "Exchange Act"), and the rules and regulations of
the Commission thereunder. On the Effective Date, the Registration Statement
did not contain any untrue statement of a material fact and did not omit to
state any material fact required to be stated therein or necessary in order to
make the statements therein not misleading; and, on the Effective Date the
Prospectus did not and, on the Closing Date and any later date on which Option
Stock is to be purchased, will not contain any untrue statement of a material
fact or omit to state any material fact necessary in order to make the
statements therein, in the light of the circumstances under which they were
made, not misleading; provided, however, that none of the representations and
warranties in this subparagraph (iv) shall apply to statements in, or omissions
from, the Registration Statement or the Prospectus made in reliance upon and in
conformity with information herein or otherwise furnished in writing to the
Company by or on behalf of the Underwriters for use in the Registration
Statement or the Prospectus.
    

   
                                  (v)      The Stock is duly and validly
authorized, is (or, in the case of shares of the Stock to be sold by the
Company and The Prudential Insurance Company of America, a Selling Stockholder
("Prudential"), will be, when issued and sold to the Underwriters as provided
herein) duly and validly issued, fully paid and nonassessable and conforms to
the description thereof in the Prospectus. No further approval or authority of
the stockholders or the Board of Directors of the Company will be required for
the issuance and sale of the Stock as contemplated herein. The authorized
capital stock of the Company conforms as to legal matters to the description
thereof contained in the Prospectus. The shares of Common Stock outstanding
    


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prior to the issuance of the Underwritten Stock and, if any, the Option Stock
have been duly authorized and are validly issued, fully paid and
non-assessable.

   
                                  (vi)     Prior to the Closing Date, the Stock
to be issued and sold by the Company will be authorized for listing on the
Nasdaq National Market (herein called "NNM") upon official notice of issuance.
    

                                  (vii)    Except as specifically disclosed in
the Registration Statement, the Company does not have outstanding any options
to purchase, or any preemptive rights, or other rights to subscribe or to
purchase or rights of co-sale, any securities or obligations convertible into,
or any contracts or commitments to issue or sell or register for sale, shares
of its capital stock or any such options, rights, convertible securities or
obligations.

   
                                  (viii)   The consolidated financial
statements of the Company, together with related notes and schedules as set
forth in the Registration Statement ("Financial Statements"), present fairly
the financial position and the results of operations of the Company and its
subsidiaries, taken as a whole, at the indicated dates and for the indicated
periods. The Financial Statements have been prepared in accordance with
generally accepted accounting principles, consistently applied through the
period involved, and all adjustments necessary for a fair presentation of
results for such periods have been made. The selected and summary financial
data and the tables set forth under "Results of Operations" and "Quarterly
Results of Operations" in the Management's Discussion and Analysis of Financial
Condition and Results of Operations section, included in the Registration
Statement, present fairly the information shown therein and have been compiled
on a basis consistent with the Financial Statements presented in the
Registration Statement.
    

                                  (ix)     Neither the Company nor any of its
subsidiaries is in violation or default under any provision of its charter
documents or bylaws, as currently in effect, or any indenture, license,
mortgage, lease, franchise, permit, deed of trust or other agreement or
instrument to which such corporation is a party or by which such corporation or
any of its properties is bound or may be affected, except where such violation
or default would not have a Material Adverse Effect.

                                  (x)      The Company has full legal right,
power and authority to enter into this Agreement and perform the transactions
contemplated hereby. This Agreement has been duly authorized, executed and
delivered by the Company and is a valid and binding agreement on the part of
the Company, enforceable in accordance with its terms, except as rights to
indemnity and contribution hereunder may be limited by applicable laws and
except as the enforcement hereof may be limited by applicable bankruptcy,
insolvency, reorganization, moratorium or other similar laws affecting
creditors' rights generally, or by general equitable principles. The execution
and performance of this Agreement and the consummation of the transactions
herein contemplated do not and will not: (i) conflict with, or result in a
breach of, or violation of, any of the terms or provisions of, or constitute,
either by itself or upon notice or the passage of time or both, a default
under, any indenture, license, mortgage, lease, franchise, permit, deed of
trust or other agreement or instrument to which the Company or any of its


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subsidiaries is a party or by which any such corporation or any of its
properties is bound or may be affected, except where such breach, violation or
default would not have a Material Adverse Effect, (ii) violate any of the
provisions of the charter documents or bylaws of any such corporation, except
where such violation would not have a Material Adverse Effect or (iii) violate
any material order, judgment, statute, rule or regulation applicable to any
such corporation or of any regulatory, administrative or governmental body or
agency having jurisdiction over any such corporation or any of its properties,
except where such violation would not have a Material Adverse Effect.
    

                                  (xi)     Except as disclosed in the
Prospectus, there is not any pending or, to the Company's knowledge, threatened
action, suit, claim or proceeding against the Company or any of its
subsidiaries or any of their respective officers or any of their properties,
assets or rights before any court or governmental agency or body or otherwise
which (i) might have a Material Adverse Effect, or (ii) might prevent
consummation of the transactions contemplated hereby or (iii) is required to be
disclosed in the Registration Statement; and there are no contracts or
documents of the Company or any of its subsidiaries that are required to be
described in the Prospectus or to be filed as exhibits to the Registration
Statement which have not been fairly and accurately described in all material
respects in the Prospectus or filed as exhibits to the Registration Statement
as the case may be. The contracts so described in the Prospectus are in full
force and effect on the date hereof; and neither the Company nor any of its
subsidiaries nor, to the Company's knowledge any other party, is in breach of
or default under any of such contracts.

                                  (xii)    Except as disclosed in the
Prospectus, the Company owns or possesses adequate rights to use all patents,
patent rights, inventions, trade secrets, know-how, trademarks, service marks,
trade names and copyrights described or referred to in the Prospectus as owned
or used by it or which are necessary for the conduct of its businesses as
described in the Prospectus; the Company has not received any notice of, and
the Company has no knowledge of, any infringement of or conflict with asserted
rights of others with respect to any patent, patent rights, inventions, trade
secrets, know-how, trademarks, service marks, trade names or copyrights which,
singly or in the aggregate, might reasonably have a Material Adverse Effect.

                                  (xiii)   The Company has not taken and will
not take, directly or indirectly, any action designed to or that might be
reasonably expected to cause or result in stabilization or manipulation of the
price of the Common Stock to facilitate the sale or resale of the Stock.

                                  (xiv)    Except as set forth in the
Prospectus, the Company and each of its subsidiaries has all permits, licenses,
approvals and registrations required to be issued under applicable federal,
state and local laws, statutes and regulations relating to the protection of
human health, safety, the environment and natural resources ("Environmental
Laws") with respect to its business as conducted and as proposed to be
conducted in the Prospectus and is in substantial compliance with the terms and
conditions thereunder except where failure to have such permits, licenses,
approvals and registrations, or to be in compliance thereunder would not have a
Material Adverse Effect.  Except as set forth in the Prospectus, the Company
and each of



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its subsidiaries is in substantial compliance with and there are no past or
present conditions, activities, actions or plans which may prevent substantial
compliance with, any current or past law related to the manufacture,
processing, distribution, use, treatment, storage, disposal, transport or
handling, or the release, emission or discharge of any hazardous substance or
hazardous waste ("Hazardous Substance Issues") or any regulations, plans,
judgments, injunctions or notices promulgated or approved thereunder which may
give rise to any liability of the Company or its subsidiaries or otherwise form
the basis of any ongoing or threatened claims, actions, demands, suits,
proceedings, hearings, studies or investigations against or relating to the
Company or its subsidiaries, the property owned or leased by the Company or its
subsidiaries that are based on or related to any Hazardous Substance Issues
except for such non-compliance which would not have a Material Adverse Effect.

                                  (xv)     Except as set forth in the
Prospectus, there has been no material disposal, release or threatened release
of any hazardous substance or hazardous waste on, from or under the property
owned or leased currently or in the past by the Company, its subsidiaries or
any predecessor, other than those authorized by permit under federal, state and
local laws except such as would not have a Material Adverse Effect.  For
purposes of this Agreement, the terms "disposal," "release," "hazardous
substance" and "hazardous waste" shall have the definitions assigned thereto
under federal, state and local laws applicable to the Company, its
subsidiaries, the Company's or any subsidiary's assets and the property owned
or leased by the Company, including without limitation the Federal
Comprehensive Environmental Response, Compensation and Liability Act of 1980,
42 U.S.C. Section 9601 et seq., as amended, and any regulations promulgated
thereto.

                                  (xvi)    Except as set forth in the
Prospectus, no disposal or release of a hazardous substance or hazardous waste
has come to be located on or beneath and remain located on or beneath any of
the real property owned or leased currently or in the past by the Company, any
subsidiary or any predecessor or upon which any of the property owned or leased
currently or in the past by the Company, any subsidiary or any predecessor are,
or have been, held or maintained except such as would not have a Material
Adverse Effect.

                                  (xvii)   Except as set forth in the
Prospectus, the Company and its subsidiaries have no knowledge of the possible
or actual presence, disposal, release or threatened release of any hazardous
substance or hazardous waste on or under any adjacent properties to the any
property owned or leased currently or in the past by the Company, any
subsidiary or any predecessor except such as would not have a Material Adverse
Effect.

   
                          (b)     Each of the Selling Stockholders severally
and not jointly hereby represents and warrants to the Underwriters and the
Company as follow (provided that the representation and warranty set forth in
subsection (ii) below is made solely by Efratom Holding, Inc. ("Efratom")):
    

   
                                  (i)      Such Selling Stockholder has, or
will have upon delivery to the Underwriters, good and valid title to all the
shares of Stock to be sold by such Selling Stockholder hereunder, free and
clear of all liens, encumbrances, equities, security interests and
    


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claims whatsoever, with full right and authority to deliver the same hereunder,
subject, in the case of each Selling Stockholder, to the rights of any
custodian pursuant to a custody agreement (herein called the "Custodian"), and
that upon the delivery of and payment for such shares of the Stock hereunder,
the several Underwriters will receive good and valid title thereto, free and
clear of all liens, encumbrances, equities, security interests and claims
whatsoever.
    

   
                                  (ii)     Efratom has duly authorized,
executed and delivered, in the form heretofore furnished to the Underwriters, a
Custody Agreement and Power of Attorney (the "Custody Agreement and Power of
Attorney") appointing Louis B. Horwitz and David A. Young as attorneys-in-fact
(collectively, the "Attorneys" and individually, an "Attorney") and appointing
Chase Mellon Shareholder Services as Custodian; the Custody Agreement and Power
of Attorney constitutes a valid and binding agreement on the part of Efratom,
enforceable in accordance with its terms, except as the enforcement thereof may
be limited by applicable bankruptcy, insolvency, reorganization, moratorium or
other similar laws relating to or affecting creditors' rights generally or by
general equitable principles; and each of Efratom's Attorneys, acting alone, is
authorized to execute and deliver this Agreement and the certificate referred
to in Section 9(k) hereof on behalf of Efratom, to determine the purchase price
to be paid by the several Underwriters to Efratom as provided in Section 3
hereof, to authorize the delivery of the shares of Stock to be sold by Efratom
under this Agreement and to duly endorse (in blank or otherwise) the
certificate or certificates representing such Stock or a stock power or powers
with respect thereto, to accept payment therefor, and otherwise to act on
behalf of Efratom in connection with this Agreement.
    

   
                                  (iii)    All consents, approvals,
authorizations and orders required for the execution and delivery by Efratom of
the Custody Agreement and Power of Attorney, the execution and delivery by or
on behalf of such Selling Stockholder of this Agreement and the sale and
delivery of the shares of Stock to be sold by such Selling Stockholder under
this Agreement (other than, at the time of the execution hereof (if the
Registration Statement has not yet been declared effective by the issuance of
the order of the Commission declaring the Registration Statement effective and
such consents, approvals, authorizations or orders as may be necessary under
state or other securities or Blue Sky laws) have been obtained and are in full
force and effect; such Selling Stockholder, if other than a natural person, has
been duly organized and is validly existing in good standing under the laws of
the jurisdiction of its organization as the type of entity that it purports to
be; and such Selling Stockholder has full legal right, power and authority to
enter into and perform its obligations under this Agreement and such Custody
Agreement and Power of Attorney (if applicable), and to sell, assign, transfer
and deliver the Stock to be sold by such Selling Stockholder under this
Agreement.
    

   
                                  (iv)     Certificates in negotiable form for
the shares of the Stock to be sold by Efratom have been placed in custody under
a Custody Agreement and Power of Attorney for delivery under this Agreement
with the Custodian and in the case of shares to be sold by Prudential pursuant
hereto upon exercise of a warrant to purchase Common Stock Prudential shall
have deposited with their legal counsel irrevocable instructions to exercise
such warrant (the "Irrevocable Instructions"); Efratom specifically agrees that
the shares of the Stock represented by the certificates so held in custody for
such Selling Stockholder, and Prudential
    


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specifically agrees that the shares of the Stock to be issued upon exercise of
the warrant, are subject to the interests of the several Underwriters and the
Company, that the arrangements made by such Selling Stockholder for such
custody, or the arrangements made for such exercise, including the Power of
Attorney provided for in such Custody Agreement and Power of Attorney, or the
Irrevocable Instructions, are to that extent irrevocable, and that the
obligations of such Selling Stockholder shall not be terminated by any act of
such Selling Stockholder or by operation of law, whether by the death or
incapacity of such Selling Stockholder (or, in the case of a Selling
Stockholder that is not an individual, the dissolution or liquidation of such
Selling Stockholder) or the occurrence of any other event; if any such death,
incapacity, dissolution, liquidation or other such event should occur before
the delivery of such shares of the Stock hereunder, certificates for such
shares of the Stock shall be delivered by the Custodian in accordance with the
terms and conditions of this Agreement as if such death, incapacity,
dissolution, liquidation or other event had not occurred, regardless of whether
the Custodian shall have received notice of such death, incapacity,
dissolution, liquidation or other event.
    

   
                                  (v)      All information relating to such
Selling Stockholder and the shares of Stock to be sold by such Selling
Stockholder pursuant hereto or set forth in the Registration Statement or the
Prospectus under the caption "Principal and Selling Stockholders" furnished in
writing by such Selling Stockholder is, and at the time the Registration
Statement became or becomes, as the case may be, effective and at all times
subsequent thereto up to and on the Closing Date, was or will be, true, correct
and complete, and does not, and at the time the Registration Statement became
or becomes, as the case may be, effective and at all times subsequent thereto
up to and on the Closing Date (hereinafter defined) will not, contain any
untrue statement of a material fact or omit to state a material fact required
to be stated therein or necessary to make such information not misleading.
    

   
                                  (vi)     Such Selling Stockholder will comply
with all agreements and satisfy all conditions on its part to be complied with
or satisfied pursuant to this Agreement on or prior to the Closing Date and
will advise one of its Attorneys and Hambrecht & Quist LLC prior to the Closing
Date if any statement to be made on behalf of such Selling Stockholder in the
certificate contemplated by Section 9(k) would be inaccurate if made as of the
Closing Date.
    

                                  (vii)    Such Selling Stockholder has not
taken and will not take, directly or indirectly, any action designed to or that
might reasonably be expected to cause or result in stabilization or
manipulation of the price of the Common Stock to facilitate the sale or resale
of the Stock.

                                  (viii)   Such Selling Stockholder does not
have, or has waived prior to the date hereof, any preemptive right, co-sale
right or right of first refusal or other similar right to purchase any of the
Stock that are to be sold by the Company or any of the other Selling
Stockholders to the Underwriters pursuant to this Agreement; such Selling
Stockholder does not have, or has waived prior to the date hereof, any
registration right or other similar right to participate in the offering made
by the Prospectus, other than such rights of participation as have been
satisfied by the participation of such Selling Stockholder in the transactions
to which this Agreement relates in accordance with the terms of this Agreement;
and such Selling Stockholder


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<PAGE>   9
does not own any warrants, options or similar rights to acquire, and does not
have any right or arrangement to acquire, any capital stock, rights, warrants,
options or other securities from the Company, other than those described in the
Registration Statement and the Prospectus and any document incorporated therein
by reference.

                                  (ix)     Such Selling Stockholder has not
distributed and will not distribute any prospectus or other offering material
in connection with the offering and sale of the Stock.


                 3.       PURCHASE OF THE STOCK BY THE UNDERWRITERS.

                          (a)     On the basis of the representations and
warranties and subject to the terms and conditions herein set forth, the
Company agrees to issue and sell 1,000,000 shares of the Underwritten Stock to
the several Underwriters, each Selling Stockholder agrees to sell to the
several Underwriters the number of shares of the Underwritten Stock set forth
in Schedule II opposite the name of such Selling Stockholder, and each of the
Underwriters agrees to purchase from the Company and the Selling Stockholders
the respective aggregate number of shares of Underwritten Stock set forth
opposite its name in Schedule I.  The price at which such shares of
Underwritten Stock shall be sold by the Company and the Selling Stockholders
and purchased by the several Underwriters shall be $    per share.  The
obligation of each Underwriter to the Company and each of the Selling
Stockholders shall be to purchase from the Company and the Selling Stockholders
that number of shares of the Underwritten Stock which represents the same
proportion of the total number of shares of the Underwritten Stock to be sold
by each of the Company and the Selling Stockholders pursuant to this Agreement
as the number of shares of the Underwritten Stock set forth opposite the name
of such Underwriter in Schedule I hereto represents of the total number of
shares of the Underwritten Stock to be purchased by all Underwriters pursuant
to this Agreement, as adjusted by you in such manner as you deem advisable to
avoid fractional shares.  In making this Agreement, each Underwriter is
contracting severally and not jointly; except as provided in paragraphs (b) and
(c) of this Section 3, the agreement of each Underwriter is to purchase only
the respective number of shares of the Underwritten Stock specified in Schedule
I.

                          (b)     If for any reason one or more of the
Underwriters shall fail or refuse (otherwise than for a reason sufficient to
justify the termination of this Agreement under the provisions of Section 8 or
9 hereof) to purchase and pay for the number of shares of the Stock agreed to
be purchased by such Underwriter or Underwriters, the Company or the Selling
Stockholders shall immediately give notice thereof to you, and the
non-defaulting Underwriters shall have the right within 24 hours after the
receipt by you of such notice to purchase, or procure one or more other
Underwriters to purchase, in such proportions as may be agreed upon between you
and such purchasing Underwriter or Underwriters and upon the terms herein set
forth, all or any part of the shares of the Stock which such defaulting
Underwriter or Underwriters agreed to purchase.  If the non-defaulting
Underwriters fail so to make such arrangements with respect to all such shares
and portion, the number of shares of the Stock which each non-defaulting
Underwriter is otherwise obligated to purchase under this Agreement shall be
automatically increased on a pro rata basis to absorb the remaining shares and
portion which the defaulting


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<PAGE>   10
Underwriter or Underwriters agreed to purchase; provided, however, that the
non-defaulting Underwriters shall not be obligated to purchase the shares and
portion which the defaulting Underwriter or Underwriters agreed to purchase if
the aggregate number of such shares of the Stock exceeds 10% of the total
number of shares of the Stock which all Underwriters agreed to purchase
hereunder.  If the total number of shares of the Stock which the defaulting
Underwriter or Underwriters agreed to purchase shall not be purchased or
absorbed in accordance with the two preceding sentences, the Company and the
Selling Stockholders shall have the right, within 24 hours next succeeding the
24-hour period above referred to, to make arrangements with other underwriters
or purchasers satisfactory to you for purchase of such shares and portion on
the terms herein set forth.  In any such case, either you or the Company and
the Selling Stockholders shall have the right to postpone the Closing Date
determined as provided in Section 5 hereof for not more than seven business
days after the date originally fixed as the Closing Date pursuant to said
Section 5 in order that any necessary changes in the Registration Statement,
the Prospectus or any other documents or arrangements may be made.  If neither
the non-defaulting Underwriters nor the Company and the Selling Stockholders
shall make arrangements within the 24-hour periods stated above for the
purchase of all the shares of the Stock which the defaulting Underwriter or
Underwriters agreed to purchase hereunder, this Agreement shall be terminated
without further act or deed and without any liability on the part of the
Company or the Selling Stockholders to any non-defaulting Underwriter and
without any liability on the part of any non-defaulting Underwriter to the
Company or the Selling Stockholders.  Nothing in this paragraph (b), and no
action taken hereunder, shall relieve any defaulting Underwriter from liability
in respect of any default of such Underwriter under this Agreement.

   
                          (c)     On the basis of the representations,
warranties and covenants herein contained, and subject to the terms and
conditions herein set forth, the Company grants an option to the several
Underwriters to purchase, severally and not jointly, up to 367,917 shares of
the Option Stock at the same price per share as the Underwriters shall pay for
the Underwritten Stock.  The option may be exercised only to cover
over-allotments in the sale of the Underwritten Stock by the Underwriters and
may be exercised in whole or in part at any time (but not more than once) on or
before the thirtieth day after the date of this Agreement upon written or
telegraphic notice by you to the Company setting forth the aggregate number of
shares of the Option Stock as to which the several Underwriters are exercising
the option.  Delivery of certificates for the shares of Option Stock, and
payment therefor, shall be made as provided in Section 5 hereof.  The number of
shares of the Option Stock to be purchased by each Underwriter shall be the
same percentage of the total number of shares of the Option Stock to be
purchased by the several Underwriters as such Underwriter is purchasing of the
Underwritten Stock, as adjusted by you in such manner as you deem advisable to
avoid fractional shares.
    


                 4.       OFFERING BY UNDERWRITERS.

                          (a)     The terms of the initial public offering by
the Underwriters of the Stock to be purchased by them shall be as set forth in
the Prospectus.  The Underwriters may from time to time change the public
offering price after the closing of the initial public offering and increase or
decrease the concessions and discounts to dealers as they may determine.


                                       10
<PAGE>   11
                          (b)     The information set forth in the last
paragraph on the front cover page and under "Underwriting" in the Registration
Statement, any Preliminary Prospectus and the Prospectus relating to the Stock
filed by the Company (insofar as such information relates to the Underwriters)
constitutes the only information furnished by the Underwriters to the Company
for inclusion in the Registration Statement, any Preliminary Prospectus, and
the Prospectus, and you on behalf of the respective Underwriters represent and
warrant to the Company that the statements made therein are correct.


                 5.       DELIVERY OF AND PAYMENT FOR THE STOCK.

                          (a)     Delivery of certificates for the shares of
the Underwritten Stock and the Option Stock (if the option granted by Section
3(c) hereof shall have been exercised not later than 7:00 A.M., San Francisco
time, on the date two business days preceding the Closing Date), and payment
therefor, shall be made at the office of Stradling, Yocca, Carlson & Rauth, 660
Newport Center Drive, Suite 1600, Newport Beach, California, at 7:00 a.m., San
Francisco time, on the [fourth] business day after the date of this Agreement,
or at such time on such other day, not later than seven full business days
after such fourth business day, as shall be agreed upon in writing by the
Company, the Selling Stockholders and you.  The date and hour of such delivery
and payment (which may be postponed as provided in Section 3(b) hereof) are
herein called the Closing Date.

                          (b)     If the option granted by Section 3(c) hereof
shall be exercised after 7:00 a.m., San Francisco time, on the date two
business days preceding the Closing Date, delivery of certificates for the
shares of Option Stock, and payment therefor, shall be made at the office of
Stradling, Yocca, Carlson & Rauth, 660 Newport Center Drive, Suite 1600,
Newport Beach, California, at 7:00 a.m., San Francisco time, on the third
business day after the exercise of such option.

   
                          (c)     Payment for the Stock purchased from the
Company shall be made to the Company or its order, payment for the Stock
purchased from Efratom shall be made to the Custodian, for the account of
Efratom, and payment for the Stock purchased from Prudential shall be made to
Prudential or its order, in each case by one or more certified or official bank
check or checks in same day funds or wire transfer, if requested by any party.
Such payment shall be made upon delivery of certificates for the Stock to you
for the respective accounts of the several Underwriters against receipt
therefor signed by you.  Certificates for the Stock to be delivered to you
shall be registered in such name or names and shall be in such denominations as
you may request at least one business day before the Closing Date, in the case
of Underwritten Stock, and at least one business day prior to the purchase
thereof, in the case of the Option Stock.  Such certificates will be made
available to the Underwriters for inspection, checking and packaging at the
offices of Lewco Securities Corporation, 2 Broadway, New York, New York 10004
on the business day prior to the Closing Date or, in the case of the Option
Stock, by 3:00 p.m., New York time, on the business day preceding the date of
purchase.
    

                 It is understood that you, individually and not on behalf of
the Underwriters, may (but shall not be obligated to) make payment to the
Company and the Selling Stockholders for

                                       11
<PAGE>   12
shares to be purchased by any Underwriter whose check shall not have been
received by you on the Closing Date or any later date on which Option Stock is
purchased for the account of such Underwriter.  Any such payment by you shall
not relieve such Underwriter from any of its obligations hereunder.

   
                 6.       FURTHER AGREEMENTS OF THE COMPANY AND THE SELLING
STOCKHOLDERS.  Each of the Company or the Selling Stockholders, as the case may
be, respectively covenants and agrees as follows:
    

                          (a)     The Company will (i) prepare and timely file
with the Commission under Rule 424(b) a Prospectus containing information
previously omitted at the time of effectiveness of the Registration Statement
in reliance on Rule 430A and (ii) not file any amendment to the Registration
Statement or supplement to the Prospectus of which you shall not previously
have been advised and furnished with a copy or to which you shall have
reasonably objected in writing or which is not in compliance with the
Securities Act or the rules and regulations of the Commission.

                          (b)     The Company will promptly notify each
Underwriter in the event of (i) the request by the Commission for amendment of
the Registration Statement or for supplement to the Prospectus or for any
additional information, (ii) the issuance by the Commission of any stop order
suspending the effectiveness of the Registration Statement, (iii) the
institution or notice of intended institution of any action or proceeding for
that purpose, (iv) the receipt by the Company of any notification with respect
to the suspension of the qualification of the Stock for sale in any
jurisdiction, or (v) the receipt by it of notice of the initiation or
threatening of any proceeding for such purpose.  The Company and the Selling
Stockholders will make every reasonable effort to prevent the issuance of such
a stop order and, if such an order shall at any time be issued, to obtain the
withdrawal thereof at the earliest possible moment.

                          (c)     The Company will (i) on or before the Closing
Date, deliver to you a signed copy of the Registration Statement as originally
filed and of each amendment thereto filed prior to the time the Registration
Statement becomes effective and, promptly upon the filing thereof, a signed
copy of each post-effective amendment, if any, to the Registration Statement
(together with, in each case, all exhibits thereto unless previously furnished
to you) and will also deliver to you, for distribution to the Underwriters, a
sufficient number of additional conformed copies of each of the foregoing (but
without exhibits) so that one copy of each may be distributed to each
Underwriter, (ii) as promptly as possible deliver to you and send to the
several Underwriters, at such office or offices as you may designate, as many
copies of the Prospectus as you may reasonably request, and (iii) thereafter
from time to time during the period in which a prospectus is required by law to
be delivered by an Underwriter or dealer, likewise send to the Underwriters as
many additional copies of the Prospectus and as many copies of any supplement
to the Prospectus and of any amended prospectus, filed by the Company with the
Commission, as you may reasonably request for the purposes contemplated by the
Securities Act.


                                       12
<PAGE>   13
                          (d)     If at any time during the period in which a
prospectus is required by law to be delivered by an Underwriter or dealer any
event relating to or affecting the Company, or of which the Company shall be
advised in writing by you, shall occur as a result of which it is necessary, in
the opinion of counsel for the Company or of counsel for the Underwriters, to
supplement or amend the Prospectus in order to make the Prospectus not
misleading in the light of the circumstances existing at the time it is
delivered to a purchaser of the Stock, the Company will forthwith prepare and
file with the Commission a supplement to the Prospectus or an amended
prospectus so that the Prospectus as so supplemented or amended will not
contain any untrue statement of a material fact or omit to state any material
fact necessary in order to make the statements therein, in the light of the
circumstances existing at the time such Prospectus is delivered to such
purchaser, not misleading.  If, after the initial public offering of the Stock
by the Underwriters and during such period, the Underwriters shall propose to
vary the terms of offering thereof by reason of changes in general market
conditions or otherwise, you will advise the Company in writing of the proposed
variation, and, if in the opinion either of counsel for the Company or of
counsel for the Underwriters such proposed variation requires that the
Prospectus be supplemented or amended, the Company will forthwith prepare and
file with the Commission a supplement to the Prospectus or an amended
prospectus setting forth such variation.  The Company authorizes the
Underwriters and all dealers to whom any of the Stock may be sold by the
several Underwriters to use the Prospectus, as from time to time amended or
supplemented, in connection with the sale of the Stock in accordance with the
applicable provisions of the Securities Act and the applicable rules and
regulations thereunder for such period.

                          (e)     Prior to the filing thereof with the
Commission, the Company will submit to you, for your information, a copy of any
post-effective amendment to the Registration Statement and any supplement to
the Prospectus or any amended prospectus proposed to be filed.

                          (f)     The Company will cooperate, when and as
requested by you, in the qualification of the Stock for offer and sale under
the securities or blue sky laws of such jurisdictions as you may designate and,
during the period in which a prospectus is required by law to be delivered by
an Underwriter or dealer, in keeping such qualifications in good standing under
said securities or blue sky laws; provided, however, that the Company shall not
be obligated to file any general consent to service of process or to qualify as
a foreign corporation in any jurisdiction in which it is not so qualified.  The
Company will, from time to time, prepare and file such statements, reports, and
other documents as are or may be required to continue such qualifications in
effect for so long a period as you may reasonably request for distribution of
the Stock.

                          (g)     During a period of five years commencing with
the date hereof, the Company will furnish to you, and to each Underwriter who
may so request in writing, copies of all periodic and special reports furnished
to stockholders of the Company and of all information, documents and reports
filed with the Commission.

                          (h)     Not later than the 45th day following the end
of the fiscal quarter first occurring after the first anniversary of the
Effective Date, the Company will make generally


                                       13
<PAGE>   14
available to its security holders an earnings statement in accordance with
Section 11(a) of the Securities Act and Rule 158 thereunder.

   
                          (i)     The Company agrees to pay all costs and
expenses incident to the performance of their respective obligations under this
Agreement, including all costs and expenses incident to (i) the preparation,
printing and filing with the Commission and the National Association of
Securities Dealers, Inc. ("NASD") of the Registration Statement, any
Preliminary Prospectus and the Prospectus, (ii) the furnishing to the
Underwriters of copies of any Preliminary Prospectus and of the several
documents required by paragraph (c) of this Section 6 to be so furnished,
(iii) the printing of this Agreement and related documents delivered to the
Underwriters, (iv) the preparation, printing and filing of all supplements and
amendments to the Prospectus referred to in paragraph (d) of this Section 6,
(v) the furnishing to you and the Underwriters of the reports and information
referred to in paragraph (g) of this Section 6 and (vi) the printing and
issuance of stock certificates, including the transfer agent's fees.  The
Selling Stockholders will pay any transfer taxes incident to the transfer to
the Underwriters of the shares the Stock being sold by the Selling
Stockholders.
    

                          (j)     The Company agrees to reimburse you, for the
account of the several Underwriters, for blue sky fees and related
disbursements (including counsel fees and disbursements and cost of printing
memoranda for the Underwriters) paid by or for the account of the Underwriters
or their counsel in qualifying the Stock under state securities or blue sky
laws and in the review of the offering by the NASD.

   
                          (k)     The provisions of paragraphs (i) and (j) of
this Section are intended to relieve the Underwriters from the payment of the
expenses and costs which the Company hereby agrees to pay and shall not affect
any agreement which the Company and the Selling Stockholders may make, or may
have made, for the sharing of any such expenses and costs.
    

                          (l)     The Company hereby agrees that, without the
prior written consent of Hambrecht & Quist LLC on behalf of the Underwriters,
the Company will not, for a period of 90 days following the commencement of the
public offering of the Stock by the Underwriters, directly or indirectly, (i)
sell, offer, contract to sell, make any short sale, pledge, sell any option or
contract to purchase, purchase any option or contract to sell, grant any
option, right or warrant to purchase or otherwise transfer or dispose of any
shares of Common Stock or any securities convertible into or exchangeable or
exercisable for or any rights to purchase or acquire Common Stock or (ii) enter
into any swap or other agreement that transfers, in whole or in part, any of
the economic consequences or ownership of Common Stock, whether any such
transaction described in clause (i) or (ii) above is to be settled by delivery
of Common Stock or such other securities, in cash or otherwise.  The foregoing
sentence shall not apply to (A) the Stock to be sold to the Underwriters
pursuant to this Agreement, (B) shares of Common Stock issued by the Company
upon the exercise of options granted under the stock option plans of the
Company (the "Option Plans"), all as described in footnote (1) to the table
under the caption "Capitalization" in the Preliminary Prospectus, and
(C) options to purchase Common Stock granted under the Option Plans.


                                       14
<PAGE>   15
                 7.       INDEMNIFICATION AND CONTRIBUTION.

   
                          (a)     Subject to the provisions of paragraph (f) of
this Section 7, the Company and the Selling Stockholders jointly and severally
agree to indemnify and hold harmless each Underwriter and each person
(including each partner or officer thereof) who controls any Underwriter within
the meaning of Section 15 of the Securities Act from and against any and all
losses, claims, damages or liabilities, joint or several, to which such
indemnified parties or any of them may become subject under the Securities Act,
the Securities Exchange Act of 1934, as amended (herein called the Exchange
Act), or the common law or otherwise, and the Company and the Selling
Stockholders jointly and severally agree to reimburse each such Underwriter and
controlling person for any legal or other expenses (including, except as
otherwise hereinafter provided, reasonable fees and disbursements of counsel)
incurred by the respective indemnified parties in connection with defending
against any such losses, claims, damages or liabilities or in connection with
any investigation or inquiry of, or other proceeding which may be brought
against, the respective indemnified parties, in each case arising out of or
based upon (i) any untrue statement or alleged untrue statement of a material
fact contained in the Registration Statement (including the Prospectus as part
thereof and any Rule 462(b) registration statement) or any post-effective
amendment thereto (including any Rule 462(b) registration statement), or the
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading, or
(ii) any untrue statement or alleged untrue statement of a material fact
contained in any Preliminary Prospectus or the Prospectus (as amended or as
supplemented if the Company shall have filed with the Commission any amendment
thereof or supplement thereto) or the omission or alleged omission to state
therein a material fact necessary in order to make the statements therein, in
the light of the circumstances under which they were made, not misleading;
provided, however, that (1) the indemnity agreements of the Company and the
Selling Stockholders contained in this paragraph (a) shall not apply to any
such losses, claims, damages, liabilities or expenses if such statement or
omission was made in reliance upon and in conformity with information furnished
as herein stated or otherwise furnished in writing to the Company by or on
behalf of any Underwriter for use in any Preliminary Prospectus or the
Registration Statement or the Prospectus or any such amendment thereof or
supplement thereto, (2) the indemnity agreement contained in this paragraph (a)
with respect to any Preliminary Prospectus shall not inure to the benefit of
any Underwriter from whom the person asserting any such losses, claims,
damages, liabilities or expenses purchased the Stock which is the subject
thereof (or to the benefit of any person controlling such Underwriter) if at or
prior to the written confirmation of the sale of such Stock a copy of the
Prospectus (or the Prospectus as amended or supplemented) was not sent or
delivered to such person and the untrue statement or omission of a material
fact contained in such Preliminary Prospectus was corrected in the Prospectus
(or the Prospectus as amended or supplemented) unless the failure is the result
of noncompliance by the Company with paragraph (c) of Section 6 hereof, and (3)
each Selling Stockholder shall only be liable under this paragraph with respect
to (A) information identified in Section 2(b)(v) hereof pertaining to such
Selling Stockholder furnished by or on behalf of such Selling Stockholder
expressly for use in any Preliminary Prospectus or the Registration Statement
or the Prospectus or any such amendment thereof or supplement thereto or (B)
facts that would constitute a breach of any representation or warranty of such
Selling Stockholder set forth in Section 2(b)(v) hereof.
    


                                       15
<PAGE>   16
The indemnity agreements of the Company and the Selling Stockholders contained
in this paragraph (a) and the representations and warranties of the Company and
the Selling Stockholders contained in Section 2 hereof shall remain operative
and in full force and effect regardless of any investigation made by or on
behalf of any indemnified party and shall survive the delivery of and payment
for the Stock.

   
                          (b)     Each Underwriter severally agrees to
indemnify and hold harmless the Company, each of its officers who signs the
Registration Statement on his own behalf or pursuant to a power of attorney,
each of its directors, each other Underwriter and each person (including each
partner or officer thereof) who controls the Company or any such other
Underwriter within the meaning of Section 15 of the Securities Act, and the
Selling Stockholders (and each person who controls such Selling Stockholder)
from and against any and all losses, claims, damages or liabilities, joint or
several, to which such indemnified parties or any of them may become subject
under the Securities Act, the Exchange Act, or the common law or otherwise and
to reimburse each of them for any legal or other expenses (including, except as
otherwise hereinafter provided, reasonable fees and disbursements of counsel)
incurred by the respective indemnified parties in connection with defending
against any such losses, claims, damages or liabilities or in connection with
any investigation or inquiry of, or other proceeding which may be brought
against, the respective indemnified parties, in each case arising out of or
based upon (i) any untrue statement or alleged untrue statement of a material
fact contained in the Registration Statement (including the Prospectus as part
thereof and any Rule 462(b) registration statement) or any post-effective
amendment thereto (including any Rule 462(b) registration statement) or the
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading or
(ii) any untrue statement or alleged untrue statement of a material fact
contained in the Prospectus (as amended or as supplemented if the Company shall
have filed with the Commission any amendment thereof or supplement thereto) or
the omission or alleged omission to state therein a material fact necessary in
order to make the statements therein, in the light of the circumstances under
which they were made, not misleading, if such statement or omission was made in
reliance upon and in conformity with information furnished as herein stated or
otherwise furnished in writing to the Company by or on behalf of such
indemnifying Underwriter for use in the Registration Statement or the
Prospectus or any such amendment thereof or supplement thereto.  The indemnity
agreement of each Underwriter contained in this paragraph (b) shall remain
operative and in full force and effect regardless of any investigation made by
or on behalf of any indemnified party and shall survive the delivery of and
payment for the Stock.
    

                          (c)     Each party indemnified under the provision of
paragraphs (a) and (b) of this Section 7 agrees that, upon the service of a
summons or other initial legal process upon it in any action or suit instituted
against it or upon its receipt of written notification of the commencement of
any investigation or inquiry of, or proceeding against, it in respect of which
indemnity may be sought on account of any indemnity agreement contained in such
paragraphs, it will promptly give written notice (herein called the Notice) of
such service or notification to the party or parties from whom indemnification
may be sought hereunder.  No indemnification provided for in such paragraphs
shall be available to any party who shall fail so to give the



                                       16
<PAGE>   17
Notice if the party to whom such Notice was not given was unaware of the
action, suit, investigation, inquiry or proceeding to which the Notice would
have related and was prejudiced by the failure to give the Notice, but the
omission so to notify such indemnifying party or parties of any such service or
notification shall not relieve such indemnifying party or parties from any
liability which it or they may have to the indemnified party for contribution
or otherwise than on account of such indemnity agreement.  Any indemnifying
party shall be entitled at its own expense to participate in the defense of any
action, suit or proceeding against, or investigation or inquiry of, an
indemnified party.  Any indemnifying party shall be entitled, if it so elects
within a reasonable time after receipt of the Notice by giving written notice
(herein called the Notice of Defense) to the indemnified party, to assume
(alone or in conjunction with any other indemnifying party or parties) the
entire defense of such action, suit, investigation, inquiry or proceeding, in
which event such defense shall be conducted, at the expense of the indemnifying
party or parties, by counsel chosen by such indemnifying party or parties and
reasonably satisfactory to the indemnified party or parties; provided, however,
that (i) if the indemnified party or parties reasonably determine that there
may be a conflict between the positions of the indemnifying party or parties
and of the indemnified party or parties in conducting the defense of such
action, suit, investigation, inquiry or proceeding or that there may be legal
defenses available to such indemnified party or parties different from or in
addition to those available to the indemnifying party or parties, then counsel
for the indemnified party or parties shall be entitled to conduct the defense
to the extent reasonably determined by such counsel to be necessary to protect
the interests of the indemnified party or parties and (ii) in any event, the
indemnified party or parties shall be entitled to have counsel chosen by such
indemnified party or parties participate in, but not conduct, the defense.  If,
within a reasonable time after receipt of the Notice, an indemnifying party
gives a Notice of Defense and the counsel chosen by the indemnifying party or
parties is reasonably satisfactory to the indemnified party or parties, the
indemnifying party or parties will not be liable under paragraphs (a) through
(c) of this Section 7 for any legal or other expenses subsequently incurred by
the indemnified party or parties in connection with the defense of the action,
suit, investigation, inquiry or proceeding, except that (A) the indemnifying
party or parties shall bear the legal and other expenses incurred in connection
with the conduct of the defense as referred to in clause (i) of the proviso to
the preceding sentence and (B) the indemnifying party or parties shall bear
such other expenses as it or they have authorized to be incurred by the
indemnified party or parties. If, within a reasonable time after receipt of the
Notice, no Notice of Defense has been given, the indemnifying party or parties
shall be responsible for any legal or other expenses incurred by the
indemnified party or parties in connection with the defense of the action,
suit, investigation, inquiry or proceeding.

                          (d)     If the indemnification provided for in this
Section 7 is unavailable or insufficient to hold harmless an indemnified party
under paragraph (a) or (b) of this Section 7, then each indemnifying party, in
lieu of indemnifying such indemnified party, shall contribute to the amount
paid or payable by such indemnified party as a result of the losses, claims,
damages or liabilities referred to in paragraph (a) or (b) of this Section 7
(i) in such proportion as is appropriate to reflect the relative benefits
received by each indemnifying party from the offering of the Stock or (ii) if
the allocation provided by clause (i) above is not permitted by applicable law,
in such proportion as is appropriate to reflect not only the relative benefits
referred to in clause (i) above but also the relative fault of each
indemnifying party in connection with the


                                       17
<PAGE>   18
statements or omissions that resulted in such losses, claims, damages or
liabilities, or actions in respect thereof, as well as any other relevant
equitable considerations.  The relative benefits received by the Company and
the Selling Stockholders on the one hand and the Underwriters on the other
shall be deemed to be in the same respective proportions as the total net
proceeds from the offering of the Stock received by the Company and the Selling
Stockholders and the total underwriting discount received by the Underwriters,
as set forth in the table on the cover page of the Prospectus, bear to the
aggregate public offering price of the Stock. Relative fault shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fact or the omission or alleged omission to
state a material fact relates to information supplied by each indemnifying
party and the parties' relative intent, knowledge, access to information and
opportunity to correct or prevent such untrue statement or omission.

   
                 The parties agree that it would not be just and equitable if
contributions pursuant to this paragraph (d) were to be determined by pro rata
allocation (even if the Underwriters were treated as one entity for such
purpose) or by any other method of allocation which does not take into account
the equitable considerations referred to in the first sentence of this
paragraph (d).  The amount paid by an indemnified party as a result of the
losses, claims, damages or liabilities, or actions in respect thereof, referred
to in the first sentence of this paragraph (d) shall be deemed to include any
legal or other expenses reasonably incurred by such indemnified party in
connection with investigation, preparing to defend or defending against any
action or claim which is the subject of this paragraph (d) to the extent such
indemnified party would be entitled to indemnification for such legal or other
expenses under paragraph 7(c). Notwithstanding the provisions of this paragraph
(d), no Underwriter shall be required to contribute any amount in excess of the
underwriting discount applicable to the Stock purchased by such Underwriter. No
person guilty of fraudulent misrepresentation (within the meaning of Section
11(f) of the Securities Act) shall be entitled to contribution from any person
who was not guilty of such fraudulent misrepresentation.  The Underwriters'
obligations in this paragraph (d) to contribute are several in proportion to
their respective underwriting obligations and not joint.
    

                 Each party entitled to contribution agrees that upon the
service of a summons or other initial legal process upon it in any action
instituted against it in respect of which contribution may be sought, it will
promptly give written notice of such service to the party or parties from whom
contribution may be sought, but the omission so to notify such party or parties
of any such service shall not relieve the party from whom contribution may be
sought from any obligation it may have hereunder or otherwise (except as
specifically provided in paragraph (c) of this Section 7).

                          (e)     Neither the Company nor the Selling
Stockholders will, without the prior written consent of each Underwriter,
settle or compromise or consent to the entry of any judgment in any pending or
threatened claim, action, suit or proceeding in respect of which
indemnification may be sought hereunder (whether or not such Underwriter or any
person who controls such Underwriter within the meaning of Section 15 of the
Securities Act or Section 20 of the Exchange Act is a party to such claim,
action, suit or proceeding) unless such settlement, compromise or consent
includes an unconditional release of such Underwriter and each such controlling
person from all liability arising out of such claim, action, suit or
proceeding.


                                       18
<PAGE>   19
                          (f)     The liability of each Selling Stockholder
under the indemnity and reimbursement agreements contained in the provisions of
this Section 7 and Section 11 hereof shall be limited to an amount equal to the
initial public offering price of the stock sold by such Selling Stockholder to
the Underwriters.  The Company and the Selling Stockholders may agree, as among
themselves and without limiting the rights of the Underwriters under this
Agreement, as to the respective amounts of such liability for which they each
shall be responsible.

   
                          (g)     The Company hereby acknowledges the
indemnification agreements with the Selling Stockholders contained in that
certain Stockholder's Agreement dated March 17, 1995 (the "Stockholder's
Agreement") and that certain Common Stock Purchase Warrant dated September 27,
1996 (the "Warrant").  The Company agrees that nothing contained in this
Agreement shall modify the Company's obligations under the Stockholder's
Agreement or the Warrant.
    

   
                 8.       TERMINATION.  This Agreement may be terminated by you
at any time prior to the Closing Date by giving written notice to the Company
and the Selling Stockholders if after the date of this Agreement trading in the
Common Stock shall have been suspended, or if there shall have occurred (i) the
engagement in hostilities or an escalation of major hostilities by the United
States or the declaration of war or a national emergency by the United States
on or after the date hereof, (ii) any outbreak of hostilities or other national
or international calamity or crisis or change in economic or political
conditions if the effect of such outbreak, calamity, crisis or change in
economic or political conditions in the financial markets of the United States
would, in the Underwriters' reasonable judgment, make the offering or delivery
of the Stock impracticable, (iii) suspension of trading in securities generally
or a material adverse decline in value of securities generally on the New York
Stock Exchange, the American Stock Exchange, or The Nasdaq Stock Market, or
limitations on prices (other than limitations on hours or numbers of days of
trading) for securities on either such exchange or system, (iv) the enactment,
publication, decree or other promulgation of any federal or state statute,
regulation, rule or order of, or commencement of any proceeding or
investigation by, any court, legislative body, agency or other governmental
authority which in the Underwriters' reasonable opinion materially and
adversely affects or will materially or adversely affect the business or
operations of the Company, (v) declaration of a banking moratorium by either
federal or New York State authorities or (vi) the taking of any action by any
federal, state or local government or agency in respect of its monetary or
fiscal affairs which in the Underwriters' reasonable opinion has a material
adverse effect on the securities markets in the United States.  If this
Agreement shall be terminated pursuant to this Section 8, there shall be no
liability of the Company or the Selling Stockholders to the Underwriters and no
liability of the Underwriters to the Company or the Selling Stockholders;
provided, however, that in the event of any such termination the Company agrees
to indemnify and hold harmless the Underwriters from all costs or expenses
incident to the performance of the obligations of the Company and the Selling
Stockholders under this Agreement, including all costs and expenses referred to
in paragraphs (i) and (j) of Section 6 hereof.
    

                 9.       CONDITIONS OF UNDERWRITERS' OBLIGATIONS.  The
obligations of the several Underwriters to purchase and pay for the Stock shall
be subject to the performance by the


                                       19
<PAGE>   20
Company and by the Selling Stockholders of all their respective obligations to
be performed hereunder at or prior to the Closing Date or any later date on
which Option Stock is to be purchased, as the case may be, and to the following
further conditions:

                          (a)     The Registration Statement shall have become
effective; and no stop order suspending the effectiveness thereof shall have
been issued and no proceedings therefor shall be pending or threatened by the
Commission.

                          (b)     The legality and sufficiency of the sale of
the Stock hereunder and the validity and form of the certificates representing
the Stock, all corporate proceedings and other legal matters incident to the
foregoing, and the form of the Registration Statement and of the Prospectus
(except as to the financial statements contained therein), shall have been
approved at or prior to the Closing Date by Gunderson Dettmer Stough Villeneuve
Franklin & Hachigian, LLP, counsel for the Underwriters.

   
                          (c)     You shall have received opinions addressed to
the Underwriters dated the Closing Date from (i) Stradling, Yocca, Carlson &
Rauth, counsel for the Company, covering the matters set forth in Annex A
hereto, (ii) Donald C. Lewis, Vice President and Secretary of Efratom Holding,
Inc., a Selling Stockholder, covering the matters set forth in Annex B hereto,
(iii) James F. Evert, Assistant General Counsel of The Prudential Insurance
Company of America, a Selling Stockholder, covering the matters set forth in
Annex C hereto and (iv) Kelly, Hart & Hallman, environmental counsel for the
Company covering the matters set forth in Annex D hereto and if Option Stock is
purchased at any date after the Closing Date, additional opinions from each
counsel set forth in (i) and (iv) above, addressed to the Underwriters and
dated such later date, confirming that the statements expressed as of the
Closing Date in such opinions remain valid as of such later date.
    

                          (d)     You shall be satisfied that (i) as of the
Effective Date, the statements made in the Registration Statement and the
Prospectus were true and correct and neither the Registration Statement nor the
Prospectus omitted to state any material fact required to be stated therein or
necessary in order to make the statements therein, respectively, not
misleading, (ii) since the Effective Date, no event has occurred which should
have been set forth in a supplement or amendment to the Prospectus which has
not been set forth in such a supplement or amendment, (iii) since the
respective dates as of which information is given in the Registration Statement
in the form in which it originally became effective and the Prospectus
contained therein, there has not been any material adverse change or any
development involving a prospective material adverse change in or affecting the
business, properties, financial condition or results of operations of the
Company and its subsidiaries, taken as a whole, whether or not arising from
transactions in the ordinary course of business, and, since such dates, except
in the ordinary course of business, the Company does not have/neither the
Company nor any of its subsidiaries has entered into any material transaction
not referred to in the Registration Statement in the form in which it
originally became effective and the Prospectus contained therein, (iv) neither
the Company nor any of its subsidiaries has any material contingent obligations
which are not disclosed in the Registration Statement and the Prospectus,
(v) there are not any pending or known threatened legal proceedings to which
the Company or any of its subsidiaries


                                       20
<PAGE>   21
is a party or of which property of the Company or any of its subsidiaries is
the subject which are material and which are not disclosed in the Registration
Statement and the Prospectus, (vi) there are not any franchises, contracts,
leases or other documents which are required to be filed as exhibits to the
Registration Statement which have not been filed as required, (vii) the
representations and warranties of the Company herein are true and correct in
all material respects as of the Closing Date or any later date on which Option
Stock is to be purchased, as the case may be, and (viii) there has not been any
material change in the market for securities in general or in political,
financial or economic conditions from those reasonably foreseeable as to render
it impracticable in your reasonable judgment to make a public offering of the
Stock, or a material adverse change in market levels for securities in general
(or those of companies in particular) or financial or economic conditions which
render it inadvisable to proceed.

                          (e)     You shall have received on the Closing Date
and on any later date on which Option Stock is purchased a certificate, dated
the Closing Date or such later date, as the case may be, and signed by the
President and the Chief Financial Officer of the Company, stating that the
respective signers of said certificate have carefully examined the Registration
Statement in the form in which it originally became effective and the
Prospectus contained therein and any supplements or amendments thereto, and
that the statements included in clauses (i) through (vii) of paragraph (d) of
this Section 9 are true and correct.

                          (f)     You shall have received from Price Waterhouse
LLP, a letter or letters, addressed to the Underwriters and dated the Closing
Date and any later date on which Option Stock is purchased, confirming that
they are independent public accountants with respect to the Company within the
meaning of the Securities Act and the applicable published rules and
regulations thereunder and based upon the procedures described in their letter
delivered to you concurrently with the execution of this Agreement (herein
called the Original Letter), but carried out to a date not more than three
business days prior to the Closing Date or such later date on which Option
Stock is purchased (i) confirming, to the extent true, that the statements and
conclusions set forth in the Original Letter are accurate as of the Closing
Date or such later date, as the case may be, and (ii) setting forth any
revisions and additions to the statements and conclusions set forth in the
Original Letter which are necessary to reflect any changes in the facts
described in the Original Letter since the date of the Original Letter or to
reflect the availability of more recent financial statements, data or
information.  The letters shall not disclose any change, or any development
involving a prospective change, in or affecting the business or properties of
the Company or any of its subsidiaries which, in your sole judgment, makes it
impractical or inadvisable to proceed with the public offering of the Stock or
the purchase of the Option Stock as contemplated by the Prospectus.

                          (g)     You shall have received from Price Waterhouse
LLP a letter stating that their review of the Company's system of internal
accounting controls, to the extent they deemed necessary in establishing the
scope of their examination of the Company's financial statements as at December
31, 1996, did not disclose any weakness in internal controls that they
considered to be material weaknesses.


                                       21
<PAGE>   22
                          (h)     You shall have been furnished evidence in
usual written or telegraphic form from the appropriate authorities of the
several jurisdictions, or other evidence satisfactory to you, of the
qualification referred to in paragraph (f) of Section 6 hereof.

                          (i)     Prior to the Closing Date, the Stock to be
issued and sold by the Company shall have been duly authorized for listing by
the Nasdaq National Market upon official notice of issuance.

                          (j)     On or prior to the Closing Date, you shall
have received from all directors, officers, and beneficial holders of more than
5% of the outstanding Common Stock agreements, in form reasonably satisfactory
to Hambrecht & Quist LLC, stating that without the prior written consent of
Hambrecht & Quist LLC on behalf of the Underwriters, such person or entity will
not, for a period of 90 days following the commencement of the public offering
of the Stock by the Underwriters, directly or indirectly, (i) sell, offer,
contract to sell, make any short sale, pledge, sell any option or contract to
purchase, purchase any option or contract to sell, grant any option, right or
warrant to purchase or otherwise transfer or dispose of any shares of Common
Stock or any securities convertible into or exchangeable or exercisable for or
any rights to purchase or acquire Common Stock or (ii) enter into any swap or
other agreement that transfers, in whole or in part, any of the economic
consequences or ownership of Common Stock, whether any such transaction
described in clause (i) or (ii) above is to be settled by delivery of Common
Stock or such other securities, in cash or otherwise.

   
                          (k)     You shall be satisfied that, and you shall
have received a certificate, dated the Closing Date, or any later date on which
Option Stock are to be purchased, as the case may be, from the Attorneys for
each Selling Stockholder to the effect that, as of the Closing Date, or any
later date on which Option Stock are to be purchased, as the case may be, they
have not been informed that:
    

   
                                  (i)      The representations and warranties
made by such Selling Stockholder herein are not true or correct in any material
respect on the Closing Date or on any later date on which Option Stock are to
be purchased, as the case may be; or
    

   
                                  (ii)     Such Selling Stockholder has not
complied with any obligation or satisfied any condition which is required to be
performed or satisfied on the part of such Selling Stockholder at or prior to
the Closing Date or any later date on which Option Stock are to be purchased,
as the case may be.
    

                 All the agreements, opinions, certificates and letters
mentioned above or elsewhere in this Agreement shall be deemed to be in
compliance with the provisions hereof only if Gunderson Dettmer Stough
Villeneuve Franklin & Hachigian, LLP, counsel for the Underwriters, shall be
satisfied that they comply in form and scope.

   
                 In case any of the conditions specified in this Section 9
shall not be fulfilled, this Agreement may be terminated by you by giving
notice to the Company and to the Selling Stockholders.  Any such termination
shall be without liability of the Company or the Selling Stockholders to the
Underwriters and without liability of the Underwriters to the Company or the
    


                                       22
<PAGE>   23
   
Selling Stockholders; provided, however, that (i) in the event of such
termination, the Company agrees to indemnify and hold harmless the Underwriters
from all costs or expenses incident to the performance of the obligations of
the Company and the Selling Stockholders under this Agreement, including all
costs and expenses referred to in paragraphs (i) and (j) of Section 6 hereof,
and (ii) if this Agreement is terminated by you because of any refusal or
failure on the part of the Company or the Selling Stockholders to perform any
agreement herein, to fulfill any of the conditions herein, or to comply with
any provision hereof other than by reason of a default by any of the
Underwriters, the Company will reimburse the Underwriters severally upon demand
for all reasonable out-of-pocket expenses (including reasonable fees and
disbursements of counsel) that shall have been incurred by them in connection
with the transactions contemplated hereby.  Such indemnity and reimbursement
shall be the only liabilities of the Company to the Underwriters in such
events.
    

   
                 10.      CONDITIONS OF THE OBLIGATION OF THE COMPANY AND THE
SELLING STOCKHOLDERS.  The obligation of the Company and the Selling
Stockholders to deliver the Stock shall be subject to the conditions that
(a) the Registration Statement shall have become effective and (b) no stop
order suspending the effectiveness thereof shall be in effect and no
proceedings therefor shall be pending or threatened by the Commission.  The
obligations of the Selling Stockholders to deliver the Stock shall also be
subject to receipt by such Selling Stockholder of the opinion of Stradling,
Yocca, Carlson & Rauth referred to in Section 9(c) hereof addressed to the
Selling Stockholders.
    

                 In case either of the conditions specified in this Section 10
shall not be fulfilled, this Agreement may be terminated by the Company and the
Selling Stockholders by giving notice to you. Any such termination shall be
without liability of the Company and the Selling Stockholders to the
Underwriters and without liability of the Underwriters to the Company or the
Selling Stockholders; provided, however, that in the event of any such
termination the Company and the Selling Stockholders jointly and severally
agree to indemnify and hold harmless the Underwriters from all costs or
expenses incident to the performance of the obligations of the Company and the
Selling Stockholders under this Agreement, including all costs and expenses
referred to in paragraphs (i) and (j) of Section 6 hereof.

   
                 11.      REIMBURSEMENT OF CERTAIN EXPENSES.  In addition to
its other  obligations under Section 7 of this Agreement, the Company agrees to
reimburse on a quarterly basis the Underwriters for all reasonable legal and
other expenses incurred in connection with investigating or defending any
claim, action, investigation, inquiry or other proceeding arising out of or
based upon any statement or omission, or any alleged statement or omission,
described in Section 7(a) of this Agreement, and subject to clause (3) thereof,
notwithstanding the absence of a judicial determination as to the propriety and
enforceability of the obligations under this Section 11 and the possibility
that such payments might later be held to be improper; provided, however, that
(i) to the extent any such payment is ultimately held to be improper, the
persons receiving such payments shall promptly refund them and (ii) such
persons shall provide to the Company, upon request, reasonable assurances of
their ability to effect any refund, when and if due.
    



                                       23
<PAGE>   24
                 12.      PERSONS ENTITLED TO BENEFIT OF AGREEMENT.  This
Agreement shall inure to the benefit of the Company, the Selling Stockholders
and the several Underwriters and, with respect to the provisions of Section 7
hereof, the several parties (in addition to the Company, the Selling
Stockholders and the several Underwriters) indemnified under the provisions of
said Section 7, and their respective personal representatives, successors and
assigns.  Nothing in this Agreement is intended or shall be construed to give
to any other person, firm or corporation any legal or equitable remedy or claim
under or in respect of this Agreement or any provision herein contained.  The
term "successors and assigns" as herein used shall not include any purchaser,
as such purchaser, of any of the Stock from any of the several Underwriters.

                 13.      NOTICES.  Except as otherwise provided herein, all
communications hereunder shall be in writing or by facsimile and, if to the
Underwriters, shall be mailed, sent by facsimile or delivered to Hambrecht &
Quist LLC, One Bush Street, San Francisco, California 94104; and if to the
Company, shall be mailed, , sent by facsimile or delivered to it at its office,
9975 Toledo Way, Irvine, California 92618, Attention:  Louis B. Horwitz,
President and Chief Executive Officer; and if to the Selling Stockholders,
shall be mailed, , sent by facsimile or delivered to the Selling Stockholders
in care of Louis B. Horwitz or David A. Young at Datum Inc., 9975 Toledo Way,
Irvine, California  92618.  All notices given by facsimile shall be promptly
confirmed by letter.

                 14.      MISCELLANEOUS.  The reimbursement, indemnification
and contribution agreements contained in this Agreement and the
representations, warranties and covenants in this Agreement shall remain in
full force and effect regardless of (a) any termination of this Agreement, (b)
any investigation made by or on behalf of any Underwriter or controlling person
thereof, or by or on behalf of the Company or the Selling Stockholders or their
respective directors or officers, and (c) delivery and payment for the Stock
under this Agreement; provided, however, that if this Agreement is terminated
prior to the Closing Date, the provisions of paragraphs (g), (h) and (l) of
Section 6 hereof shall be of no further force or effect.

                 This Agreement may be executed in two or more counterparts,
each of which shall be deemed an original, but all of which together shall
constitute one and the same instrument.

                 This Agreement shall be governed by, and construed in
accordance with, the laws of the State of California.



                                       24
<PAGE>   25
                 Please sign and return to the Company and to the Selling
Stockholders in care of the Company the enclosed duplicates of this letter,
whereupon this letter will become a binding agreement among the Company, the
Selling Stockholders and the several Underwriters in accordance with its terms.

                               Very truly yours,

                               DATUM INC.

                               By:
                                   ------------------------------------------
                                   Louis B. Horwitz
                                   President and Chief Executive Officer


                               SELLING STOCKHOLDERS:

                               EFRATOM HOLDING, INC.

                               By
                                  -------------------------------------------
                               Name
                                    -----------------------------------------
                               Title
                                     ----------------------------------------

                               THE PRUDENTIAL INSURANCE COMPANY OF AMERICA

                               By
                                  -------------------------------------------
                               Name
                                    -----------------------------------------
                               Title
                                     ----------------------------------------

The foregoing Agreement is hereby confirmed
and accepted as of the date first above written.

HAMBRECHT & QUIST LLC
OPPENHEIMER & CO., INC.
VAN KASPER & COMPANY
  By Hambrecht & Quist LLC

By 
   ---------------------------------------------
               Managing Director

Acting on behalf of the several Underwriters,
including themselves, named in Schedule I hereto.
<PAGE>   26
                                   SCHEDULE I

                                  UNDERWRITERS


                                                        NUMBER OF 
                                                       SHARES TO BE
UNDERWRITERS                                            PURCHASED
------------                                           ------------
Hambrecht & Quist LLC . . . . . . . . . . . . . 

Oppenheimer & Co. Inc.  . . . . . . . . . . . . 

Van Kasper & Company  . . . . . . . . . . . . . 





                                                        ---------
           Total  . . . . . . . . . . . . . . . 
                                                        =========
<PAGE>   27
                                  SCHEDULE II

                              SELLING STOCKHOLDERS

   
                                                                NUMBER OF 
                                                              SHARES TO BE
NAME AND ADDRESS OF SELLING STOCKHOLDERS                          SOLD
----------------------------------------                      ------------

Efratom Holding, Inc.
10 Longs Peak Drive
Broomfield, Colorado  80021

The Prudential Insurance Company of America
Four Embarcadero Center
Suite 2700
San Francisco, California 94111




                                                                ---------
         Total  . . . . . . . . . . . . . . . . . . .
                                                                =========
    
<PAGE>   28
                                    ANNEX A

Matters to be Covered in the Opinion of
Stradling, Yocca, Carlson & Rauth
Counsel for the Company

   
                 (i)      The Company has been duly incorporated and is validly
existing as a corporation in good standing under the laws of the State of
Delaware, is duly qualified as a foreign corporation and in good standing in
California, and is so qualified and in good standing in each jurisdiction in
which, to its knowledge, the ownership or leasing of property requires such
qualification (except where the failure to be so qualified would not have a
material adverse effect on the business, properties, condition (financial or
otherwise) or results of operations or prospects of the Company and its
subsidiaries taken as whole and has full corporate power and authority to own
or lease its properties and conduct its business as described in the
Registration Statement;
    

                 (ii)     The Company owns of record, and to our knowledge owns
beneficially all of the outstanding shares of capital stock of each subsidiary
of the Company, and each subsidiary of the Company has been duly incorporated
and is validly existing as a corporation in good standing under the laws of the
jurisdiction of its incorporation;

   
                 (iii)    The authorized capital stock of the Company consists
of 1,000,000 shares of Preferred Stock, $.25 par value, none of which are
issued and outstanding, and 10,000,000 shares of Common Stock, $.25 par value,
of which there are issued and outstanding of record            shares
(including the Underwritten Stock plus the number of shares of Option Stock
issued on the date hereof); proper corporate proceedings have been taken
validly to authorize such authorized capital stock; all of the outstanding
shares of such capital stock (including the Underwritten Stock plus the number
of shares of Option Stock issued on the date hereof) have been duly and validly
issued and are fully paid and nonassessable; any Option Stock purchased on or
after the Closing Date, when issued and delivered to and paid for by the
Underwriters as provided in the Underwriting Agreement, will have been duly and
validly issued and be fully paid and nonassessable; no preemptive rights or
rights of refusal exist with respect to the Stock, or the issue and sale
thereof, pursuant to the Restated Certificate of Incorporation or Bylaws of the
Company; and, to the best of such counsel's knowledge, there are no contractual
preemptive rights, rights of first refusal or rights of co-sale which exist
with respect to the issue and sale of the Stock by the Company or the sale of
Stock by the Selling Stockholders that have not been waived.  Except as
disclosed in the Registration Statement, to the best of such counsel's
knowledge the Company does not have outstanding any options to purchase, or any
other rights to subscribe for or to purchase, any securities or obligations
convertible into, or any contracts or commitments to issue or sell shares of
its capital stock or any such options, rights, convertible securities or
obligations;
    

                 (iv)     The Registration Statement has become effective under
the Securities Act and, to the best of such counsel's knowledge after due
inquiry, no stop order suspending the effectiveness of the Registration
Statement or suspending or preventing the use of the Prospectus





                                      A-1
<PAGE>   29
is in effect and no proceedings for that purpose have been instituted or are
pending or threatened by the Commission. Any required filing of the Prospectus
and any supplement thereto pursuant to Rule 424(b) of the Rules and Regulations
has been made in the manner within the time period required by such Rule
424(b).

                 (v)      The Registration Statement at the Effective Date and
the Prospectus and each amendment and supplement thereto (except as to the
financial statements and schedules and other financial data contained therein
and matters related to patents, as to which such counsel need express no
opinion) complied as to form in all material respects with the requirements of
the Securities Act, the Exchange Act and with the rules and regulations of the
Commission thereunder;

                 (vi)     The information required to be set forth in the
Registration Statement in answer to Items 9 and 10 (insofar as Item 10 relates
to the beneficial ownership of shares of Common Stock of the Company by
partners of such counsel) of Form S-2 is, to the best of such counsel's
knowledge, accurately and adequately set forth therein in all material respects
or no response is required with respect to such Items; and to such counsel's
knowledge, the description of the Company's stock option plans and the options
granted and which may be granted thereunder set forth or incorporated by
reference in the Prospectus accurately and fairly presents the information
required to be shown with respect to said plans and options to the extent
required by the Securities Act and the rules and regulations of the Commission
thereunder;

                 (vii)    To the best of such counsel's knowledge, there are no
franchises, contracts, leases, documents or legal proceedings, pending or
threatened, which in the opinion of such counsel are of a character required to
be described in the Registration Statement or the Prospectus or to be filed as
exhibits to the Registration Statement, which are not described or filed as
required, as the case may be; such franchises, contracts, leases, documents and
legal proceedings as are summarized in the Registration Statement or the
Prospectus fairly and correctly present the information disclosed with respect
thereto in all material aspects;

                 (viii)   The Underwriting Agreement has been duly authorized, 
executed and delivered by the Company;

   
    

                 (ix)     The issue and sale by the Company of the shares of
Stock sold by the Company as contemplated by the Underwriting Agreement will
not conflict with, or result in a breach of, the Restated Certificate of
Incorporation or Bylaws of the Company or any material agreement or instrument
known to such counsel to which the Company or any of its subsidiaries is a
party or by which the Company or any of its subsidiaries or any of their assets
are bound or any applicable law or regulation, or so far as is known to such
counsel, any order, writ, injunction or decree, of any jurisdiction, court or
governmental instrumentality to which the Company or any of its subsidiaries is
a party or by which the Company or any of its subsidiaries or any of their
assets are bound;

   
                 (x)      To such counsel's knowledge, all holders of
securities of the Company having rights to the registration of shares of Common
Stock, or other securities, because of the filing of the Registration Statement
by the Company are set forth in the Prospectus under the
    





                                      A-2
<PAGE>   30
   
heading "Principal and Selling Stockholders" or have waived such rights or such
rights have expired by reason of lapse of time following notification of the
Company's intent to file the Registration Statement;
    

   
                 (xi)     No consent, approval, authorization or order of any
court or governmental agency or body is required for the consummation of the
transactions contemplated in the Underwriting Agreement, except such as have
been obtained under the Securities Act and such as may be required under state
securities or blue sky laws or under the rules of the National Association of
Securities Dealers, Inc. in connection with the purchase and distribution of
the Stock by the Underwriters; and
    

                 (xii)    The Stock to be sold under the Agreement to the
Underwriters is duly authorized for quotation on the Nasdaq National Market.

   
    

                 Counsel rendering the foregoing opinion may rely as to
questions of law not involving the laws of the United States or of the State of
Delaware, upon opinions of local counsel satisfactory in form and scope to
counsel for the Underwriters. Copies of any opinions so relied upon shall be
delivered to the Representatives and to counsel for the Underwriters and the
foregoing opinion shall also state that counsel knows of no reason the
Underwriters are not entitled to rely upon the opinions of such local counsel.

                 In addition to the matters set forth above, counsel rendering
the foregoing opinion shall also include a statement to the effect that nothing
has come to the attention of such counsel that leads them to believe that the
Registration Statement (except as to the financial statements and schedules and
other financial and statistical data contained or incorporated by reference
therein, as to which such counsel need not express any opinion or belief) at
the Effective Date contained any untrue statement of a material fact or omitted
to state a material fact required to be stated therein or necessary to make the
statements therein not misleading, or that the Prospectus (except as to the
financial statements and schedules and other financial and statistical data
contained or incorporated by reference therein, as to which such counsel need
not express any opinion or belief) as of its date or at the Closing Date (or
any later date on which Option Stock is purchased), contained or contains any
untrue statement of a material fact or omitted or omits to state a material
fact necessary in order to make the statements therein, in light of the
circumstances as under which they were made, not misleading.





                                      A-3
<PAGE>   31
   
                                    ANNEX B

Matters to be Covered in the Opinion of
Donald C. Lewis, Vice President and Secretary
Efratom Holding, Inc., a Selling Stockholder

                 (i)      The Underwriting Agreement has been duly executed and
delivered by or on behalf of Efratom Holding, Inc., a Selling Stockholder
("Efratom");

                 (ii)     The Custody Agreement and Power of Attorney between
Efratom and the Custodian (as defined in the Custody Agreement and Power of
Attorney) has been duly executed and delivered by or on behalf of Efratom;

                 (iii)    Good and valid title to the shares of Stock sold by
Efratom under the Underwriting Agreement, free and clear of any adverse claim
(within the meaning of the Uniform Commercial Code), has been transferred to
the Underwriters who have severally purchased such shares of Stock under the
Underwriting Agreement, assuming for the purpose of this opinion that the
Underwriters purchased the same in good faith without notice of any adverse
claims (within the meaning of the Uniform Commercial Code);

                 (iv)     To the best of such counsel's knowledge, there are no
contractual preemptive rights, rights of first refusal or rights of co-sale
which exist with respect to the sale of Stock by Efratom that have not been
waived; and

                 (v)      No consent, approval, authorization or order of any
court or governmental agency or body is required for the consummation of the
transactions contemplated in the Underwriting Agreement, except such as have
been obtained under the Securities Act and such as may be required under state
securities or blue sky laws in connection with the purchase and distribution of
the Stock by the Underwriters.





                                      B-1
    
<PAGE>   32
   
                                    ANNEX C

Matters to be Covered in the Opinion of
James F. Evert, Assistant General Counsel of
The Prudential Insurance Company of America,
a Selling Stockholder

                 (i)      The Underwriting Agreement has been duly executed and
delivered by or on behalf of The Prudential Insurance Company of America, a
Selling Stockholder ("Prudential");

                 (ii)     Good and valid title to the shares of Stock sold by
Prudential under the Underwriting Agreement, free and clear of any adverse
claim (within the meaning of the Uniform Commercial Code), has been transferred
to the Underwriters who have severally purchased such shares of Stock under the
Underwriting Agreement, assuming for the purpose of this opinion that the
Underwriters purchased the same in good faith without notice of any adverse
claims (within the meaning of the Uniform Commercial Code);

                 (iii)    To the best of such counsel's knowledge, there are no
contractual preemptive rights, rights of first refusal or rights of co-sale
which exist with respect to the sale of Stock by Prudential that have not been
waived; and

                 (iv)     No consent, approval, authorization or order of any
court or governmental agency or body is required for the consummation of the
transactions contemplated in the Underwriting Agreement, except such as have
been obtained under the Securities Act and such as may be required under state
securities or blue sky laws in connection with the purchase and distribution of
the Stock by the Underwriters.





                                      C-1
    
<PAGE>   33
   
                                    ANNEX D

Matters to be Covered in the Opinion of
Kelly, Hart & Hallman
Environmental Counsel for the Company

                 Such counsel are familiar with the environmental issues faced
by the Company in its business and have read the Registration Statement and the
Prospectus, including particularly the portions of the Registration Statement
and the Prospectus referring to environmental issues and:

                 (i)      The statements in the Registration Statement and the
Prospectus under the captions "Risk Factors-Risks Associated with Government
Regulations-Environmental Regulations; Notice of Environmental Claim" and
"Business-Legal Proceedings," to the best of such counsel's knowledge and
belief, are accurate and complete statements or summaries of the matters
therein set forth and nothing has come to such counsel's attention that causes
such counsel to believe that the above-described portions of the Registration
Statement and the Prospectus contain any untrue statement of a material fact or
omit to state a material fact required to be stated therein or necessary in
order to make the statements therein, in light of the circumstances under which
they were made, not misleading;





                                      D-1