1998 AMENDED AND RESTATED CREDIT FACILITY AGREEMENT

     THIS AGREEMENT is made as of the 30th day of September,  1998, by and among
DETECTION SYSTEMS, INC., a corporation formed under the laws of the State of New
York  with  offices  at  130  Perinton   Parkway,   Fairport,   New  York  14450
("Detection"), RADIONICS, INC., a corporation formed under the laws of the State
of California  with offices at 1800 Abbott  Street,  Salinas,  California  93901
("Radionics"),  and FLEET NATIONAL  BANK, a national  banking  association  with
offices at One East  Avenue,  Rochester,  New York 14638 (as  successor to Fleet
Bank, "Bank").

     This Agreement amends, clarifies and supersedes in its entirety the Amended
and Restated Credit Facility Agreement among the parties to this Agreement dated
as of June 24, 1997.

     The parties hereby agree as follows:


ARTICLE 1 - DEFINITIONS

     1.1 The following terms shall have the following meanings unless otherwise
expressly stated herein:

          "Affiliate"  shall mean any entity which  directly or  indirectly,  or
     through  one or more  intermediaries,  Controls or is  Controlled  By or is
     Under Common Control with the Borrower.

          "Agency"  shall  mean the  County  of  Monroe  Industrial  Development
     Agency, a public benefit  corporation formed under the laws of the State of
     New York.

          "Applicable Base Rate Margin" shall mean the following amounts for the
     following  respective  ratios of Funded Debt to EBITDA,  calculated for the
     Borrower and Subsidiaries on a consolidated  basis and without  duplication
     in accordance with GAAP:

                        Ratio             Margin (Basis Points)
                  3 to 1 or greater               37.5
                  2 to 1 or greater and
                        less than 3 to 1          12.5
                  Less than 2 to 1                 0.0

     The Applicable  Base Rate Margin shall be adjusted at the beginning of each
     three month  period  commencing  either  March 1, July 1,  September 1, and
     December 1  respectively,  and shall be  established  for that period based
     upon  the  average  rolling  ratios  shown  by  the  Borrower's   financial
     statements for the four fiscal  quarters ending on the most recent December
     31, March 31, June 30, or September 30 respectively.
<PAGE>
          "Applicable  LIBOR Margin"  shall mean the  following  amounts for the
     following  respective  ratios of Funded Debt to EBITDA,  calculated for the
     Borrower and Subsidiaries on a consolidated  basis and without  duplication
     in accordance with GAAP:

                        Ratio             Margin (Basis Points)
                  3 to 1 or greater              155.50
                  2 to 1 or greater and
                        less than 3 to 1         118.75
                  1.75 to 1 or greater and
                        less than 2 to 1          90.00
                  Less than 1.75 to 1             70.00

          The Applicable LIBOR Margin shall be adjusted at the beginning of each
     three month  period  commencing  either  March 1, July 1,  September 1, and
     December 1  respectively,  and shall be  established  for that period based
     upon  the  average  rolling  ratios  shown  by  the  Borrower's   financial
     statements for the four fiscal  quarters ending on the most recent December
     31, March 31, June 30, or September 30 respectively.

          "Bank" shall mean Fleet National Bank (as successor to Fleet Bank) and
     its successors, legal representatives, and assigns.

          "Base Rate"  shall mean the higher of the Federal  Funds Rate plus 100
     basis points, or the Prime Rate.

          "Borrower"  shall mean Detection and Radionics,  collectively and both
     of them,  and  their  respective  successors,  legal  representatives,  and
     assigns.

          "Break  Costs"  shall  mean an  amount  equal to the  amount  (if any)
     required  to  compensate  the Bank  for any  additional  losses  (including
     without  limitation  any loss,  cost, or expense  incurred by reason of the
     liquidation  or  reemployment  of deposits or funds acquired by the Bank to
     fund or maintain the Obligations  prepaid),  costs, and expenses (including
     without  limitation  penalties)  the  Bank  incurs  as a  result  of  or in
     connection  with such  prepayment.  If by reason of an Event of Default the
     Bank elects to declare the  Obligations to be immediately  due and payable,
     then any Break Costs with respect to the  Obligations  shall become due and
     payable in the same  manner as though  Borrower  had  exercised  a right of
     prepayment.

          "Business Day" shall mean, in respect of any date that is specified in
     this Agreement to be subject to adjustment in accordance  with the Modified
     Following  Business Day Convention,  a day on which commercial banks settle
     payments  in New  York or,  if the  payment  obligation  is  calculated  by
     reference to any LIBOR Rate, London, England.
<PAGE>
          "Controls"  (including  the terms  "Controlled  By" or  "Under  Common
     Control")  shall mean but not be limited to the  ownership  of  twenty-five
     percent(25%)or  more of the  outstanding  shares  of  capital  stock of any
     corporation  having voting power for the election of directors,  whether or
     not at the same time stock of any other  class or classes has or might have
     voting power by reason of the happening of any contingency, or ownership of
     twenty-five  percent (25%) or more of any interest in any  partnership,  or
     any other  interest  by reason of which a  controlling  influence  over the
     affairs of the entity may be exercised.

          "Current  Assets" shall mean all assets  treated as current  assets in
     accordance with GAAP.

          "Current  Liabilities"  shall mean treated as current  liabilities  in
     accordance with GAAP,  including without limitation all obligations payable
     on demand or within one year after the applicable  measurement date as well
     as installment,  reimbursement, or sinking fund payments payable within one
     year  after  the  applicable  measurement  date,  but  excluding  any  such
     liabilities  which are renewable or extendable at the option of the obligor
     to a date more than one year after the applicable measurement date. Current
     Liabilities  shall not include  obligations to repurchase  Borrower  shares
     pursuant  to  the  Stock  Purchase  Agreement  dated  May 7,  1997  between
     Detection Systems, Inc. and Numerix Corp.

          "Current   Ratio"  shall  mean  Current  Assets  compared  to  Current
     Liabilities.

          "Debt" for any person or entity  shall mean (i)  indebtedness  of such
     person or entity for borrowed  money,  (ii)  obligations  of such person or
     entity for the  deferred  purchase  price of property  or services  (except
     trade  payables  incurred  in  the  ordinary  course  of  business),  (iii)
     capitalized  or  capitalizable  obligations  of such  person or entity with
     respect to leases,  (iv) the amount available for drawing under outstanding
     standby  letters of credit  issued for the account of such person or entity
     and the amount of other off-balance sheet obligations or liabilities,  each
     to the extent not otherwise treated separately as Debt, (v) all obligations
     endorsed  (other than for collection in the ordinary course of business) or
     guaranteed  by such person or entity  directly or  indirectly in any manner
     including without  limitation  contingent  obligations to purchase,  pay or
     supply  funds to any  person or entity to assure a creditor  against  loss,
     (vi)  obligations  of  such  person  or  entity  arising  under  acceptance
     facilities, or bills, notes, or similar instruments,  and (vii) obligations
     secured by a lien, security interest,  or other arrangement for the purpose
     of security on property  owned by such person or entity  whether or not the
     underlying  obligations  have been  assumed by such person or entity.  Debt
     shall not include obligations to repurchase Borrower shares pursuant to the
     Stock Purchase Agreement dated May 7, 1997 between Detection Systems,  Inc.
     and Numerix Corp.
<PAGE>
          "Distributions"  shall mean (i) dividends,  payments, or distributions
     of any kind in respect of the capital  stock,  securities  or other  equity
     interests  or rights to acquire  such equity  interests  of the  applicable
     entity (except  distributions in the form of such stock, equity securities,
     equity  interests,  or rights to acquire  equity  interests  or assets of a
     business  being   acquired),   and  (ii)   repurchases,   redemptions,   or
     acquisitions  of capital stock,  securities,  or other equity  interests or
     rights to acquire such equity interests of the Borrower or any Affilate.

          "Domestic Subsidiaries" shall mean consolidated subsidiaries organized
     under the laws of the United  States of America or any state,  territory or
     instrumentality  thereof that are wholly  owned by Detection or  Radionics.
     All Domestic  Subsidiaries  are required to (a) be Guarantors,  (b) provide
     the Bank with security  interests in all of their assets  unless  otherwise
     agreed by the Bank, and (c) except for intercompany  transactions  with the
     Borrower and other Subsidiaries, themselves comply in all respects with the
     requirements  set  forth  in  Section  8.13,  and  9.10,  and with the same
     requirements  as are  imposed  upon  the  Borrower  in  Article  11 of this
     Agreement.

          "EBITDA" shall mean, for any period and determined in accordance  with
     GAAP, net operating  income  (calculated  before Interest  Expense,  taxes,
     extraordinary  and unusual items, and income or loss attributable to equity
     in Affiliates)  plus  depreciation  and  amortization  of intangibles  less
     Distributions.

          "Environment"  means any water  including  but not  limited to surface
     water and ground water or water vapor;  any land  including land surface or
     subsurface;  stream sediments;  air; fish; wildlife;  plants; and all other
     natural resources or environmental media.

          "Environmental Laws" means all federal, state and local environmental,
     land use,  zoning,  health,  chemical  use,  safety  and  sanitation  laws,
     statutes,  ordinances,   regulations,  codes  and  rules  relating  to  the
     protection of the Environment and/or governing the use, storage, treatment,
     generation, transportation, processing, handling, production or disposal of
     Hazardous  Substances  and  the  regulations,  rules,  ordinances,  bylaws,
     policies, guidelines,  procedures,  interpretations,  decisions, orders and
     directives  of  federal,   state  and  local   governmental   agencies  and
     authorities with respect thereto.

          "Environmental  Permits"  means  all  licenses,   permits,  approvals,
     authorizations,  consents  or  registrations  required  by  any  applicable
     Environmental Laws and all applicable judicial and administrative orders in
     connection with ownership,  lease, purchase,  transfer, closure, use and/or
     operation  of the  Improvements  and/or as may be required for the storage,
     treatment, generation, transportation,  processing, handling, production or
     disposal of Hazardous Substances.

          "Environmental Report" means written reports, if any, prepared for the
     Bank by an environmental consulting or environmental engineering firm.

          "ERISA"  shall mean the  Employee  Retirement  Income  Security Act of
     1974, as amended.

          "Event of Default" shall mean the occurrence of any event described in
     Article 12 hereof.
<PAGE>
          "Federal  Funds  Rate"  shall  mean,  for any  period,  a  fluctuating
     interest  rate per  annum  equal  for each day  during  such  period to the
     weighted average of the rates on overnight federal funds  transactions with
     members of the Federal Reserve System arranged by Federal funds brokers, as
     published  for such day (or if such day is not a Business Day, for the next
     preceding  Business  Day) by the Federal  Reserve Bank of New York,  or, if
     such rate is not so  published  for any day which is a  Business  Day,  the
     average of the quotations for such day on such transactions received by the
     Bank from three Federal funds  brokers of recognized  standing  selected by
     it.

          "Fee Rate"  shall mean the rate used in  computing  the unused fee and
     computed as described in Section 2.7 of this Agreement.

          "First Tier Foreign  Subsidiary"  shall mean a Foreign  Subsidiary the
     stock of which is owned directly by the Borrower or a Domestic Subsidiary.

          "Fixed  Charges"  shall mean for the applicable  period,  (i) Interest
     Expense, (ii) provision for taxes, (iii) capital expenditures not funded by
     Funded Debt or out of  additional  paid in capital,  and (iv)  principal or
     other payments due with respect to Debt which are Current Liabilities.

          "Foreign  Subsidiary"  shall mean any Subsidiary formed under the laws
     of a  jurisdiction  other than the  United  States of America or any state,
     territory or instrumentality thereof.

          "Funded Debt" shall mean all Debt that is not a Current Liability.

          "GAAP"  shall mean  generally  accepted  accounting  principles  as in
     effect from time to time in the United States of America.

          "Guarantors"  shall mean all persons or entities that have jointly and
     severally  guaranteed all of the  Obligations in form  satisfactory  to the
     Bank, including without limitation,  all Domestic Subsidiaries.  Unless the
     Bank and the Borrower  otherwise  agree in writing,  no Foreign  Subsidiary
     shall be a Guarantor.

          "Hazardous  Substances"  means,  without  limitation,  any explosives,
     radon, radioactive materials,  asbestos, urea formaldehyde foam insulation,
     polychlorinated  biphenyls,  petroleum  and  petroleum  products,  methane,
     hazardous  materials,  hazardous wastes,  hazardous or toxic substances and
     any other material  defined as a hazardous  substance in the  Comprehensive
     Environmental Response, Compensation and Liability Act of 1980, as amended,
     42 U.S.C.  Sections 9601, et. seq.; the Hazardous Materials  Transportation
     Act,  as  amended,  49  U.S.C.   Sections  1801,  et.  seq.;  the  Resource
     Conservation  and Recovery Act, as amended,  42 U.S.C.  Sections  6901, et.
     seq.; Articles 15 and 27 of the New York State  Environmental  Conservation
     Law or any other federal, state, or local law, regulation, rule, ordinance,
     bylaw, policy, guideline,  procedure,  interpretation,  decision, order, or
     directive,  whether existing as of the date hereof,  previously enforced or
     subsequently enacted.  "Improvements" shall mean any real property owned or
     used by the Borrower.
<PAGE>
          "Increased  Cost"  shall mean any  additional  amounts  sufficient  to
     compensate  the Bank and any  assignee or  participant  of the Bank for any
     increased  costs of funding or maintaining  the  Obligations as a result of
     any law (other than  changes in tax laws  imposed on the overall net income
     or  similar  measure of  profitability  of the Bank) or  guideline  adopted
     pursuant to or arising  out of the July 1988 report of the Basle  Committee
     on Banking  Regulations and Supervisory  Practices entitled  "International
     Convergence of Capital Measurement and Capital Standards",  or the adoption
     after the date of this Agreement of any law or guideline  regarding capital
     adequacy, or any change in any of the foregoing or in the interpretation or
     administration  of any  of the  foregoing  by any  governmental  authority,
     central  bank or  comparable  agency  charged  with the  interpretation  or
     administration  thereof,  or compliance  by the Bank or the Bank's  holding
     company (or any assignee or participant of the Bank or any of their holding
     companies),  with any  request  or  directive  regarding  capital  adequacy
     (whether  or not  having the force of law) of any such  authority,  central
     bank or comparable  agency,  which has or would have the effect of reducing
     the rate of return on the Bank's  capital  or on the  capital of the Bank's
     holding  company (or the capital of any assignee or participant of the Bank
     or  any  of  their  holding  companies)  as a  direct  consequence  of  the
     transactions  contemplated by this Agreement and all related  documents and
     agreements,  the  existence  of the Bank's  commitments  hereunder,  or the
     Obligations  to a level  below that  which the Bank or the  Bank's  holding
     company (or any assignee or participant of the Bank or any of their holding
     companies) would have achieved but for such adoption,  change or compliance
     (taking into consideration the Bank's, assignee's or participant's policies
     on capital adequacy).

          "Interest  Expense"  shall mean, for the  applicable  period,  for the
     Borrower  and  Subsidiaries  determined  on a  consolidated  basis  without
     duplication,  all interest paid, capitalized,  or accrued, and amortization
     of debt discount with respect to all Debt less all related  interest income
     during  such  period and  determined  after  giving  effect to the net cost
     associated with financial  arrangements of any kind made to protect against
     fluctuations  in  interest  rates  such as  interest  rate swap  contracts,
     interest rate cap agreements, and the like.

          "LIBOR" shall mean the rate per annum (rounded  upward,  if necessary,
     to the  nearest  1/32 of one  percent)  as  determined  on the basis of the
     offered rates for deposits in United States  Dollars,  for a period of time
     comparable to the  applicable  LIBOR  Interest  Period which appears on the
     Telerate  Page 3750 as of 11:00  a.m.,  London  time on the day that is two
     London  Banking  Days  preceding  the  first  day of the  applicable  LIBOR
     Interest Period (the "Interest Setting Date");  provided,  however,  if the
     rate  described  above  does  not  appear  on the  Telerate  System  on any
     applicable Interest Setting Date, the LIBOR rate shall be the rate (rounded
     upwards as described  above,  if  necessary)  for deposits in United States
     Dollars for a the applicable Interest Period on the Reuters Page "LIBO" (or
     such  other  page as may  replace  the LIBO  Page on that  service  for the
     purpose of displaying  such rates),  as of 11:00 a.m.  (London Time) on the
     day that is two (2)  London  Banking  Days prior to the  beginning  of such
     LIBOR  Interest  Period.  If both  the  Telerate  and  Reuters  system  are
     unavailable, then the rate for that date will be determined on the basis of
     the offered  rates for  deposits in United  States  Dollars for a period of
     time  comparable to the applicable  LIBOR Interest Period which are offered
     by four major banks in the London interbank  market at approximately  11:00
     a.m.  (London  Time),  on the  day  that  is two (2)  London  Banking  Days
     preceding the first day of such LIBOR Interest Period. The principal London
     office of each of the four major  London banks will be requested to provide
     a quotation of its United States Dollar  deposit  offered rate. If at least
     two such  quotations  are  provided,  the rate  for that  date  will be the
     arithmetic  mean of the  quotations.  If  fewer  than  two  quotations  are
     provided as  requested,  the rate for that date will be  determined  on the
     basis of the rates  quoted  for loans in United  States  Dollars to leading
     European  banks for a period of time  comparable  to the  applicable  LIBOR
     Interest  Period  offered by major banks in New York City at  approximately
     11:00  a.m.  New York City time on the day that is two (2)  London  Banking
     Days  preceding the first day of such LIBOR Interest  Period.  In the event
     that the Bank is unable to obtain any such quotation as provided  above, it
     will be  deemed  that  LIBOR  for  the  LIBOR  Interest  Period  cannot  be
     determined.
<PAGE>
          In the event that LIBOR cannot be  determined,  or there is any change
     in any law or  application  thereof that makes it unlawful,  or any central
     bank or other governmental  authority asserts that it is unlawful,  for the
     Bank to hold  obligations  if the rate is determined  with reference to the
     LIBOR  (collectively,  a "LIBOR End Date"),  then  borrowings with interest
     based upon the LIBOR Rate shall not be available after the LIBOR End Date.

          "LIBOR   Interest   Period"  shall  mean  any  particular   one-month,
     three-month,  or six-month  period  during which an  applicable  LIBOR Rate
     shall be in effect.

          "LIBOR Rate" shall mean, with respect to any interest rate period, the
     rate per anum equal to LIBOR,  further  adjusted to reflect  any  Increased
     Cost.

          "Loan   Documents"  shall  mean  all  notes,   instruments,   security
     agreements,   assignments,   pledges,  mortgages,   guarantees,  and  other
     documents and agreements of any kind or nature related to this Agreement or
     the Obligations.

          "Modified Following Business Day Convention" shall mean the convention
     for adjusting any relevant date if it would otherwise fall on a day that is
     not a  Business  Day.  Terms,  when  used in  conjunction  with  the  term,
     "Modified  Following Business Day Convention",  and a date, shall mean that
     an adjustment  will be made if that date would otherwise fall on a day that
     is not a Business Day so that the date will be the first following day that
     is a Business Day.
<PAGE>
          "Mortgage"  shall mean the  mortgage  described in Section 5.5 of this
     Agreement.

          "Mortgage Loan" shall mean the mortgage loan described in Article 3 of
     this Agreement.

          "Mortgage Loan Note" shall mean the note  evidencing  the  Obligations
     related to the Mortgage Loan as described in Section 3.2 of this Agreement.

          "Mortgaged  Property" shall mean the property and improvements covered
     by and more specifically described in the Mortgage.

          "Obligations" shall include all of the Borrower's obligations owing to
     the  Bank  or any  participant  or  assignee  of the  Bank,  including  all
     obligations related to this Agreement of any kind or nature, arising now or
     in the future, including without limitation obligations under the Revolving
     Line Note, the Mortgage Loan Note, and the Term Loan Note.

          "Prime  Rate"  shall mean the  variable  per annum rate of interest so
     designated  from time to time by the Bank as its prime rate. The Prime Rate
     is a reference rate and does not  necessarily  represent the lowest or best
     rate being charged to any customer.

          "Rate  Change  Date"  shall  mean  the  first  day of each  one-month,
     three-month, or six-month period for which any LIBOR Rate applies.

          "Release"  has the  same  meaning  as given  to that  term in  Section
     101(22)  of the  Comprehensive  Environmental  Response,  Compensation  and
     Liability  Act of 1980, as amended,  42 U.S.C.  Section  9601(22),  and the
     regulations promulgated thereunder.

          "Revolving  Line" shall mean the revolving line of credit  established
     pursuant to Section 2.1 of this Agreement.

          "Revolving  Line  Note"  shall  mean the note  evidencing  Obligations
     related  to the  Revolving  Line  as  described  in  Section  2.2  of  this
     Agreement.

          "Revolving  Line  Termination  Date"  shall mean the date on which the
     Revolving Line terminates as described in Section 2.5 of this Agreement.

          "Subsidiary"  shall mean for any person or entity any  corporation  or
     other business organization of which at least a majority of the securities,
     equity,  or other ownership  interests having absolute or contingent voting
     power are directly or indirectly owned by such person or entity.

          "Tangible  Assets"  shall  mean  total  assets,   after  deduction  of
     depreciation,  depletion,  and reserves,  but  excluding  accounts from and
     other obligations  payable by officers and Affiliates and further excluding
     all assets  required to be classified  as  intangible  assets in accordance
     with GAAP (including without limitation  organizational expense, good will,
     unamortized  debt  discount,   research  and  development  costs,  patents,
     trademarks, copyrights, other intellectual property rights, franchises, and
     deferred assets).
<PAGE>
          "Tangible Net Worth" shall mean Tangible Assets less Total Liabilities
     as determined by GAAP.

          "Term Loan" shall mean the Term Loan  described  in Article 3A of this
     Agreement.

          "Term  Loan Note"  shall  mean the Term Loan Note the note  evidencing
     Obligations  related to the Term Loan as  described in Section 3A.2 of this
     Agreement.

          "Total Liabilities" shall mean the sum of all liabilities shown on the
     balance sheet as of the  applicable  date of  determination,  determined in
     accordance with GAAP.


ARTICLE 2 - REVOLVING LINE

          2.1  Revolving  Line.  Subject  to the  terms and  conditions  of this
     Agreement,  the Bank hereby  establishes  for the benefit of the Borrower a
     revolving  line of  credit in the  maximum  principal  amount of  Seventeen
     Million Dollars ($17,000,000)  outstanding at any one time. The proceeds of
     the Revolving Line shall be used for Borrower's  working capital  purposes.
     Subject to the terms of this  Agreement,  the  Borrower (or either of them)
     may borrow,  repay,  and reborrow  under the Revolving  Line so long as the
     aggregate principal amount outstanding at any time to the Borrower does not
     exceed $17,000,000. Each borrowing request must be of at least $250,000.

          2.2 Revolving Line Note.  The Borrower  shall  execute,  together with
     this Agreement, a note evidencing Obligations related to the Revolving Line
     in the form of Exhibit A attached hereto and made a part hereof.

          2.3 Interest  Rate and  Payments.  All  outstanding  amounts under the
     Revolving Line, except as specifically provided herein, shall bear interest
     until  paid in  full  (including  without  limitation  after  acceleration,
     maturity  and  judgment)  at the Base  Rate plus the  Applicable  Base Rate
     Margin.  Changes in the rate of interest  applicable to the Revolving  Line
     Note shall become effective automatically and without notice at the time of
     changes in the Base Rate.

          The Borrower, however, at least three Business Days prior to each Rate
     Change  Date may notify the Bank of its  election  to have a portion of the
     outstanding  principal  amount under the  Revolving  Line (which must be at
     least  $1,000,000 and must be an increment of $100,000) bear interest for a
     one-month,  three-month, or six month period commencing on such Rate Change
     Date at the LIBOR Rate plus the Applicable LIBOR Margin.
<PAGE>
          All  computations  of  interest  shall be made on the basis of a three
     hundred sixty (360) day year and the actual number of days elapsed.

          2.4  Payments.  Payments of all accrued  interest  under the Revolving
     Line Note shall be due and payable on the first day of each month.

          All remaining  outstanding principal and accrued interest shall be due
     and payable in full on the Revolving Line Termination Date.

          2.5 Revolving Line Termination. Unless extended in writing by the Bank
     on terms and  conditions  then  acceptable to the Bank,  the Revolving Line
     will  terminate on, the earlier of (i) July 31, 2000,  and (ii) the date of
     an Event of Default.

          2.6 Break Costs.  Any payment of any principal  outstanding  under the
     Revolving Line Note which  principal  amount is then bearing  interest at a
     rate based upon the LIBOR  Rate  shall be  accompanied  by a payment of all
     Break Costs  unless such payment is on the Rate Change Date  applicable  to
     that particular principal amount outstanding.

          2.7  Unused  Fee.  The  Borrower  shall pay to the Bank an unused  fee
     computed at the following applicable Fee Rate for the respective applicable
     ratio  of  Funded  Debt  to  EBITDA,   calculated   for  the  Borrower  and
     Subsidiaries on a consolidated basis and without  duplication in accordance
     with GAAP:

                        Ratio             Fee Rate (Basis Points)
                  3 to 1 or greater              18.87
                  2 to 1 or greater and
                        less than 3 to 1         18.75
                  Less than 2 to 1               12.50


          Each Fee Rate shall be adjusted at the  beginning  of each three month
     period  commencing  either  March 1, July 1,  September  1, and  December 1
     respectively,  and shall be  established  for that  period  based  upon the
     average rolling ratios shown by the Borrower's financial statements for the
     four fiscal  quarters ending on the most recent December 31, March 31, June
     30, or September 30 respectively.

          The unused fee shall be computed as  follows:  $17,000,000,  minus the
     average daily  outstanding  principal  balance of the Revolving Line, times
     the Fee Rate per annum.  At the end of each fiscal  quarter,  the Bank will
     bill the Borrower for the unused fee.

          2.8  Letters of Credit.  Subject to the terms and  conditions  of this
     Agreement,  the Bank will make letters of credit  available for the account
     of the  Borrower.  The  aggregate  amount  available  for drawing under all
     letters of credit  outstanding shall reduce,  dollar for dollar, the amount
     then available for advances under the Revolving Line. The letters of credit
     shall be in form  satisfactory to the Bank and the expiration dates thereof
     shall not be later than the Revolving Line Termination Date.
<PAGE>
          The  Borrower  will  pay  the  Bank's   customary   letter  of  credit
     commissions in connection with each letter of credit.

          The  Borrower,  if requested by the Bank,  will execute  reimbursement
     agreements in form  satisfactory  to the Bank,  documenting its Obligations
     with  respect  to the Letter of Credit.  All  drawings  under any letter of
     credit shall be treated as immediate advances under the Revolving Line.

          2.9 Facility  Fee.  The Borrower  shall pay to the Bank a fee equal to
     US$20,400 on the date hereof in  connection  with the renewed  availability
     under the Revolving Line.


ARTICLE 3 - MORTGAGE LOAN

          3.1  Mortgage  Loan.  Subject  to the  terms  and  conditions  of this
     Agreement,  the Bank  shall make a mortgage  loan to the  Detection  in the
     original  principal  amount of Three Million Four Hundred  Thousand Dollars
     ($3,400,000).  The proceeds of the  Mortgage  Loan shall be used to repay a
     portion of "Bridge Loan"  Obligations  to the Bank as defined in the Credit
     Facility Agreement among the Bank and the Borrower dated as of February 12,
     1996.

          3.2 Mortgage Loan Note. The Obligations relating to the Mortgage Loan
     outstanding on the date hereof shall be evidenced by a note dated as of the
     date  hereof  in the form of  Exhibit  B  attached  hereto  and made a part
     hereof.

          3.3 Interest Rate.  Outstanding amounts of the Mortgage Loan except as
     specifically  provided  herein,  shall  bear  interest  until  paid in full
     (including without limitation after acceleration,  maturity or judgment) at
     the Base Rate plus the Applicable Base Rate Margin.  Changes in the rate of
     interest  applicable  to the  Mortgage  Loan Note  shall  become  effective
     automatically and without notice at the time of changes in the Base Rate.

          Detection,  however,  at least three  Business Days prior to each Rate
     Change  Date may notify the Bank of its  election  to have a portion of the
     outstanding  principal  amount  under the  Mortgage  Loan (which must be at
     least  $1,000,000 and must be an increment of $100,000) bear interest for a
     one-month,  three-month, or six month period commencing on such Rate Change
     Date at the LIBOR Rate plus the Applicable LIBOR Margin.

          All  computations  of  interest  shall be made on the basis of a three
     hundred sixty (360) day year and the actual number of days elapsed.

          Detection will make arrangements satisfactory to the Bank, such as the
     purchase of interest  rate caps,  providing  for  protection of at least an
     aggregate of  $11,537,500  of  Obligations  under the Mortgage Loan and the
     Term Loan from interest rate increases.
<PAGE>
          3.4 Payments.  Commencing on October 1, 1998,  payments of all accrued
     interest under the Mortgage Loan Note shall be due and payable on the first
     day of each month.  In addition,  commencing on October 1, 1998,  principal
     payments  of  $20,987.65  each shall be due and payable on the first day of
     each month.

          The  Mortgage  Loan Note  shall be due and  payable in full on May 31,
     2006.

          3.5 Break Costs.  Any payment of any principal  outstanding  under the
     Mortgage Loan Note,  which principal  amount is then bearing  interest at a
     rate based upon the LIBOR Rate,  shall be  accompanied  by a payment of all
     Break Costs  unless such payment is on the Rate Change Date  applicable  to
     that particular principal amount outstanding.


ARTICLE 3A - TERM LOAN

          3A.1 Term Loan. Subject to the terms and conditions of this Agreement,
     the Bank shall make a term loan to the Detection in the principal amount of
     Fourteen  Million Three Hundred Fifty Thousand Dollars  ($14,350,000).  The
     proceeds of the Term Loan shall be used to  refinance  certain  outstanding
     obligations  of the  Borrower  owing to the Bank,  and for working  capital
     purposes.

          3A.2 Term Loan Note.  The Term Loan shall be evidenced by a note dated
     the date  hereof in the form of Exhibit C  attached  hereto and made a part
     hereof.

          3A.3  Interest  Rate.  Outstanding  amounts of the Term Loan except as
     specifically  provided  herein,  shall  bear  interest  until  paid in full
     (including without limitation after acceleration,  maturity or judgment) at
     the Base Rate plus the Applicable Base Rate Margin.  Changes in the rate of
     interest   applicable  to  the  Term  Loan  Note  shall  become   effective
     automatically and without notice at the time of changes in the Base Rate.

          Detection,  however,  at least three  Business Days prior to each Rate
     Change  Date may notify the Bank of its  election  to have a portion of the
     outstanding  principal  amount  under the Term Loan (which must be at least
     $1,000,000  and must be an  increment  of  $100,000)  bear  interest  for a
     one-month,  three-month, or six month period commencing on such Rate Change
     Date at the LIBOR Rate plus the Applicable LIBOR Margin.

          All  computations  of  interest  shall be made on the basis of a three
     hundred sixty (360) day year and the actual number of days elapsed.

          Detection will make arrangements satisfactory to the Bank, such as the
     purchase of interest  rate caps,  providing  for  protection of at least an
     aggregate of  $11,537,500  of  Obligations  under the Mortgage Loan and the
     Term Loan from interest rate increases.

          3A.4 Payments.  Commencing on October 1, 1998, payments of all accrued
     interest under the Term Loan Note shall be due and payable on the first day
     of each month. In addition, commencing on March 1, 2000, principal payments
     of  $217,424.24  each  shall be due and  payable  on the  first day of each
     month.
<PAGE>
      The Term Loan Note shall be due and payable in full on September 30, 2005.

          3A.5 Break Costs. Any payment of any principal  outstanding  under the
     Term Loan Note,  which principal  amount is then bearing interest at a rate
     based upon the LIBOR Rate,  shall be  accompanied by a payment of all Break
     Costs  unless such  payment is on the Rate Change Date  applicable  to that
     particular principal amount outstanding.

          3A.6 Facility  Fee. The Borrower  shall pay to the Bank a fee equal to
     US$17,220 on the date hereof in connection  with the initial advance of the
     Term Loan.

ARTICLE 4 - EXPENSES/DEFAULT RATE INCREASES

          4.1 Administrative Expenses. The Borrower shall pay any fees, expenses
     and disbursements,  including reasonable legal fees, of the Bank related to
     this Agreement, the Obligations,  the perfection of any collateral security
     required  hereunder,  and the transactions  contemplated by this Agreement.
     Such  payments  shall be due from  time to time  upon the Bank  giving  the
     Borrower notice of the amount of such expenses.

          4.2 Collection  Costs.  At the request of the Bank, the Borrower shall
     promptly  pay  any  expenses,   reasonable   attorney's  fees,   costs,  or
     disbursements  in connection  with  administration  of the  Obligations  or
     collection of any of the  Obligations  or  enforcement of any of the Bank's
     rights  hereunder  or under any  note,  security  agreement,  reimbursement
     agreement,  guarantee,  or other agreement related hereto.  This obligation
     shall  survive the payment of any notes  executed  hereunder.  The Bank may
     apply any  payments  of any nature  received  by it first to the payment of
     Obligations  under  this  Section  4.2,   notwithstanding  any  conflicting
     provision  contained  in this  Agreement  or any other  agreement  with the
     Borrower.

          4.3 Default  Interest Rate. Upon the failure of the Borrower to comply
     with any covenant contained in Section 8.1 or Article 10 of this Agreement,
     the rate of interest on each of the  Obligations  shall be  increased  to a
     rate at all times  equal to two  percentage  points  (2%) above the rate of
     interest which would be in effect absent such failure of  compliance,  such
     increased  rate to remain in effect  through and  including  the end of the
     fiscal  quarter in which such failure of compliance  is remedied.  Upon the
     occurrence of an Event of Default,  the provisions of this paragraph  shall
     be superseded by the provisions of the second paragraph of this Section 4.3
     which  relates  to  increases  in the  rate  of  interest  in  case  of the
     occurrence of an Event of Default.

          Upon the  occurrence  of an Event of Default,  the rate of interest on
     each of the Obligations  shall be increased to a rate at all times equal to
     two  percentage  points (2%) above the rate of  interest  which would be in
     effect absent such failure of compliance,  such increased rate to remain in
     effect through and including  payment in full of all of the Obligations and
     cancellation  of  further  commitments  to lend under  this  Agreement,  or
     written waiver of such Event of Default by the Bank.
<PAGE>
          4.4 Late  Payment  Fees.  If the  entire  amount of  principal  and/or
     interest  is not paid in full  under any of the Loan  Documents  within ten
     (10) days after the same is due,  Borrower shall pay to the Bank a late fee
     equal to two percent (2%) of the required payment.

          4.5 Prepayments Upon Default.  If by reason of an Event of Default the
     Bank elects to declare the  Obligations to be immediately  due and payable,
     then any Break Cost or  prepayment  charge with respect to the  Obligations
     shall  become due and payable in the same manner as though the Borrower had
     exercised a right of prepayment.


ARTICLE 5 - COLLATERAL AND GUARANTEES

          5.1  Security  Interests.  As  collateral  for  all  Obligations,  the
     Borrower  shall  provide to the Bank,  and shall  cause each  Guarantor  to
     provide to the Bank, a security  interest and lien in all their  respective
     assets,  including  without  limitation  machinery,  equipment,  furniture,
     fixtures, vehicles, accounts, inventory, chattel paper, interests in leases
     and property under lease,  intellectual property and proprietary interests,
     documents,  instruments,  and general intangibles.  Such security interests
     shall  be  first  liens  on  such  assets,  which  shall  not be  otherwise
     encumbered  except as specified on Schedule 5.1 attached  hereto and made a
     part hereof.

          Detection's  assets,  Radionics'  assets,  and the Guarantors'  assets
     located in Tennessee,  as well as the security interest of the Bank in such
     Tennesee assets,  shall be limited to the aggregate principal amount of One
     Hundred Fifty Thousand  Dollars  ($150,000) each, and in each case together
     with all related interest,  costs, expenses,  fees, and charges of any kind
     or nature.

          5.2 Guarantees. Radionics shall provide its unconditional guarantee of
     the  Obligations  of Detection  related to the  Mortgage  Loan and the Term
     Loan.  The  Borrower  shall  cause  all  Subsidiaries  other  than  Foreign
     Subsidiaries to become Guarantors.  The Guarantor  guarantees shall contain
     an agreement that,  except for intercompany  transactions with the Borrower
     or other Subsidiaries, such Guarantor shall comply in all respects with the
     requirements  set  forth  in  Section  8.13,  and  9.10,  and with the same
     requirements  as are  imposed  upon  the  Borrower  in  Article  11 of this
     Agreement.

          5.3 Stock  Pledge.  The  Borrower  shall pledge to the Bank (a) all of
     Borrower's shares of capital stock of Domestic Subsidiaries, and (b) in the
     case of each  First-Tier  Foreign  Subsidiary,  65% of the  total  combined
     voting power of all classes of stock of such First-Tier  Foreign Subsidiary
     entitled  to vote.  No stock of any Foreign  Subsidiary  other than a First
     Tier Foreign Subsidiary shall be pledged to the Bank.

          5.4 Landlord Waivers.  The Borrower shall deliver to the Bank a waiver
     from each landlord and mortgagee of premises on which the Bank's collateral
     is located and that is not owned by the Borrower.
<PAGE>
          5.5 Mortgage.  The Bank shall receive a Mortgage  covering the fee and
     leasehold  interests of Detection and the Agency in the facility located at
     130 Perinton Parkway, Town of Perinton, New York owned in part by Detection
     and owned in part by the Agency and leased by the Agency to Detection.  The
     Mortgage shall secure the Mortgage Loan.  Unencumbered  (except as provided
     on Schedule 5.1) and  marketable  title to the  Mortgaged  Property must be
     acceptable to the Bank's  attorneys.  The lien of the Mortgage  shall cover
     all improvements to the Mortgaged Property, ingress and egress thereto, and
     all  easements  and  licenses   necessary  or   appropriate  in  connection
     therewith.  The  lien  of the  Mortgage  also  shall  cover  all  fixtures,
     equipment,  and other  personal  property  installed upon or affixed to the
     Mortgaged Property including without limitation mechanical equipment.

          5.6  Assignment of Leases.  The Agency shall assign as collateral  for
     the  Obligations  the Lease Agreement made by the Agency to Detection dated
     as of February 1, 1982 between the Agency and Detection.


ARTICLE 6 - REPRESENTATIONS OF BORROWER

          The Borrower represents and warrants to the Bank as follows:

          6.1  Organization  and Power.  Detection  is duly  organized,  validly
     existing and in good standing  under the laws of the State of New York, and
     is duly  qualified to transact  business and in good standing in all states
     in which it is  required  to qualify or in which  failure to qualify  could
     have a material  adverse  impact on its business.  Detection has full power
     and authority to own its properties,  to carry on its business as now being
     conducted,  to execute,  deliver and perform this Agreement and all related
     documents and instruments,  and to consummate the transactions contemplated
     hereby.  Detection has no Subsidiaries or Affiliates  except  Radionics and
     those listed on Schedule 6.1.

          Radionics is duly  organized,  validly  existing and in good  standing
     under  the  laws of the  State  of  California,  and is duly  qualified  to
     transact  business  and in good  standing  in all  states  in  which  it is
     required  to qualify or in which  failure to qualify  could have a material
     adverse  impact on its business.  Radionics has full power and authority to
     own its  properties,  to carry on its business as now being  conducted,  to
     execute,  deliver and perform this Agreement and all related  documents and
     instruments,  and  to  consummate  the  transactions  contemplated  hereby.
     Radionics  has no  Subsidiaries  or Affiliates  except  Detection and those
     listed on Schedule 6.1.

          Each  Subsidiary  is  duly  organized,  validly  existing  and in good
     standing under the laws of the state or country of its organization, and is
     duly qualified to transact  business and in good standing in all states and
     countries in which it is required to qualify or in which failure to qualify
     could have a material  adverse impact on its business.  Each Subsidiary has
     full power and authority to own its properties, to carry on its business as
     now being conducted, to execute,  deliver and perform its obligations under
     this Agreement and all documents and instruments related to this Agreement,
     and to consummate the transactions contemplated hereby.
<PAGE>
          6.2 Proceedings of Borrower.  All necessary  action on the part of the
     Borrower,  including shareholder approval to the extent required,  relating
     to  authorization  of the execution and delivery of this  Agreement and all
     related  documents and instruments,  and the performance of the Obligations
     of the Borrower hereunder and thereunder has been taken. This Agreement and
     all related documents and instruments  constitute legal,  valid and binding
     obligations  of  the  Borrower,   enforceable  in  accordance   with  their
     respective  terms,  except as  enforceability  may be limited by applicable
     bankruptcy,  insolvency  or similar law  affecting  the rights of creditors
     generally, and equitable principles. The Borrower has no defenses, offsets,
     claims, or counterclaims with respect to its obligations arising under this
     Agreement  and all related  documents  and  instruments.  The execution and
     delivery by the Borrower of this  Agreement  and all related  documents and
     agreements,  and the performance by the Borrower of its  obligations  under
     this Agreement and all related  documents and  agreements  will not violate
     any provision of law or either of the Borrower's respective Certificates of
     Incorporation   or  By-laws  or   organizational   or  other  documents  or
     agreements.  The execution,  delivery and performance of this Agreement and
     all  related  documents  and  agreements,   and  the  consummation  of  the
     transactions  contemplated  hereby will not violate,  be in conflict  with,
     result in a breach of, or constitute a default under any agreement to which
     the Borrower is a party or by which any of its properties is bound,  or any
     order,   writ,   injunction,   or  decree  of  any  court  or  governmental
     instrumentality,  and will not result in the creation or  imposition of any
     lien,  charge or encumbrance upon any of its properties  except in favor of
     the Bank.

          All  necessary  action  on the  part  of  each  Subsidiary,  including
     shareholder  approval to the extent required,  relating to authorization of
     the execution and delivery of this Agreement and all related  documents and
     instruments,  and the  performance of the  Obligations  of each  Subsidiary
     hereunder and  thereunder  has been taken.  All  documents and  instruments
     related  to  this  Agreement  executed  by  each  Subsidiary   respectively
     constitute  legal,  valid  and  binding  obligations  of  such  Subsidiary,
     enforceable  in  accordance  with  their   respective   terms,   except  as
     enforceability  may be  limited by  applicable  bankruptcy,  insolvency  or
     similar law  affecting  the rights of creditors  generally,  and  equitable
     principles.  No Subsidiary has defenses,  offsets, claims, or counterclaims
     with respect to its obligations arising under all documents and instruments
     related to this Agreement. The execution and delivery by each Subsidiary or
     all documents and agreements related to this Agreement, and the performance
     by each Subsidiary of its obligations  under this Agreement and all related
     documents  and  agreements  will not  violate any  provision  of law or any
     Subsidiary's  Certificate of Incorporation or By-laws or  organizational or
     other documents or agreements.  The execution,  delivery and performance of
     all  documents  and  agreements   related  to  this   Agreement,   and  the
     consummation of the transactions  contemplated  hereby will not violate, be
     in conflict with,  result in a breach of, or constitute a default under any
     agreement  to  which  any  Subsidiary  is a party  or by  which  any of its
     properties is bound, or any order, writ, injunction, or decree of any court
     or  governmental  instrumentality,  and will not result in the  creation or
     imposition of any lien,  charge or  encumbrance  upon any of its properties
     except in favor of the Bank.

          6.3  Capitalization.  All of the  outstanding  shares and other equity
     interests of both of the Borrowers are duly authorized, validly issued, and
     fully paid.  There is no existing  contract,  debenture,  security,  right,
     option, warrant, call or similar commitment of any character calling for or
     relating to the issuance, retirement,  redemption,  purchase, or repurchase
     of shares or other equity interests of the Borrower.
<PAGE>
          All of the  outstanding  shares  and other  equity  interests  of each
     Subsidiary are duly authorized, validly issued, and fully paid. There is no
     existing contract,  debenture,  security,  right, option,  warrant, call or
     similar  commitment  of  any  character  calling  for  or  relating  to the
     issuance,  retirement,  redemption,  purchase,  or  repurchase of shares or
     other equity  interests of any Subsidiary  except with respect to Emergency
     Communications,  Inc. pursuant to the Shareholders  Agreement dated January
     26, 1993, a complete  copy of which has been  provided to the Bank prior to
     the date hereof.

          6.4  Litigation.  Except as shown on Schedule 6.4, there is no action,
     suit or  proceeding  at law or in equity or by or before  any  governmental
     instrumentality  or  other  agency  pending  or,  to the  knowledge  of the
     Borrower, threatened against or affecting the Borrower (i) that brings into
     question the legality,  validity or enforceability of this Agreement or the
     transactions  contemplated  hereby or (ii) that,  if adversely  determined,
     would have a material  adverse  effect on the  financial  condition  or the
     business of the Borrower.

          There is no action,  suit or  proceeding  at law or in equity or by or
     before any governmental  instrumentality or other agency pending or, to the
     knowledge of the Borrower,  threatened  against or affecting any Subsidiary
     (i) that brings into question the legality,  validity or  enforceability of
     this  Agreement or the  transactions  contemplated  hereby or (ii) that, if
     adversely determined, would have a material adverse effect on the financial
     condition or the business of the Subsidiary.

          6.5 Financial  Statements.  All financial  statements furnished by the
     Borrower  to the Bank are  complete  and  correct,  have been  prepared  in
     accordance  with  generally  accepted  accounting  principles  consistently
     applied throughout the periods indicated,  and fairly present the financial
     condition of the Borrower and its Subsidiaries,  as of the respective dates
     thereof and the results of their  respective  operations for the respective
     periods covered thereby.

          6.6  Adverse  Changes.  Since  the most  recent  financial  statements
     described in Section 6.5 hereof there has been no material  adverse  change
     in  the  condition,   financial  or  otherwise,  of  the  Borrower  or  its
     Subsidiaries, taken as a whole.

          6.7 Taxes.  The  Borrower has filed or caused to be filed when due all
     federal tax returns and all state and local tax returns  that are  required
     to be  filed,  and has paid or caused to be paid all taxes as shown on said
     returns or any  assessment  received.  Detection's  tax  returns  have been
     audited and tax years closed through and including  fiscal 1994.  Radionics
     tax returns have been audited and tax years  closed  through and  including
     fiscal 1992.  Each  Subsidiary has filed or caused to be filed when due all
     federal tax returns and all state and local tax returns  that are  required
     to be  filed,  and has paid or caused to be paid all taxes as shown on said
     returns or any  assessment  received.  The  Borrower's  tax returns are not
     being  audited on the date of this  Agreement and the Borrower has not been
     notified of any intention by any taxing authority to conduct such an audit.
<PAGE>
          6.8 Properties.  The Borrower and each of its  Subsidiaries  have good
     and  marketable  title to all of their  properties  and  assets,  including
     without limitation,  the properties and assets reflected in the most recent
     financial  statements  referred to in Section 6.5 hereof.  The Borrower and
     each of its Subsidiaries  have undisturbed  peaceable  possession under all
     leases under which they are  operating,  none of which  contain  unusual or
     burdensome  provisions  that may  materially  affect the  operations of the
     Borrower  and its  Subsidiaries,  and all such leases are in full force and
     effect.

          6.9  Indebtedness.  Except as disclosed  in the most recent  financial
     statements  referred  to in  Section  6.5  hereof,  the  Borrower  and  its
     Subsidiaries have no outstanding Debt.

          6.10 ERISA.  No action,  event, or transaction has occurred that could
     give rise to a lien or  encumbrance  on the assets of the  Borrower  or its
     Subsidiaries  as a result of the  application  of  relevant  provisions  of
     ERISA,  and the Borrower and its  Subsidiaries  are in material  compliance
     with all requirements of ERISA.

          6.11 Margin  Securities.  No proceeds of the Obligations  have been or
     will be used for the purpose of purchasing or carrying Margin Securities as
     defined in Regulation U of the Federal Reserve Board.

          6.12 Compliance With Law. The Borrower and its Subsidiaries are not in
     violation of any laws,  ordinances,  governmental rules,  requirements,  or
     regulations  to which they are subject  which  violation  might  materially
     adversely affect the condition (financial or otherwise) of the Borrower and
     its  Subsidiaries.  The Borrower and its Subsidiaries have obtained and are
     in compliance  with all licenses,  permits,  franchises,  and  governmental
     authorizations  necessary  for the  ownership of their  properties  and the
     conduct of their  business,  for which  failure to comply could  materially
     adversely affect the condition (financial or otherwise) of Borrower and its
     Subsidiaries.

          6.13 Patents,  Trademarks,  and  Authorizations.  The Borrower and its
     Subsidiaries own or possess all patents,  trademarks,  service marks, trade
     names, copyrights,  licenses,  authorizations,  other intellectual property
     rights,  and all rights with  respect to the  foregoing,  necessary  to the
     conduct of their  business as now conducted  without any material  conflict
     with the rights of others.

          6.14 Contracts and Agreements.  The Borrower and its  Subsidiaries are
     not parties to any contract or agreement that materially  adversely affects
     their business, property, assets, or condition, financial or otherwise, and
     the  Borrower  and  its  Subsidiaries  are in  compliance  in all  material
     respects with all contracts and agreements to which they are a party.

          6.15 Year 2000.  The Borrower and its  Subsidiaries  have reviewed the
     areas within their business and operations that could be adversely affected
     by, and have  developed or are  developing a program to address on a timely
     basis,   the  "Year  2000  Problem"   (that  is,  the  risk  that  computer
     applications  used by the  Borrower and its  Subsidiaries  may be unable to
     recognize and perform properly  date-sensitive  functions involving certain
     dates prior to and any date after December 31, 1999).  Based on such review
     and program,  the Borrower reasonably believes that the "Year 2000 Problem"
     will not have a material  adverse  effect on the  business,  operations  or
     financial conditions or prospects of the Borrower and its Subsidiaries.
<PAGE>
ARTICLE 7 - CONDITIONS OF LENDING

          The following  conditions must be satisfied before the Bank shall have
     any obligation to make any advance under this Agreement:

          7.1 Representations and Warranties. The representations and warranties
     of the Borrower  contained  herein shall be true and correct as of the date
     of making of each such  advance,  with the same effect as if made on and as
     of such date.

          7.2 No  Defaults.  There  shall  exist  no  condition  or  event  that
     constitutes  (or that,  with the giving of notice or the passage of time or
     both, would  constitute) an Event of Default under Article 12 hereof at the
     time each advance is made.

          7.3  Performance.  The Borrower shall have performed and complied with
     all agreements and conditions  required to be performed or complied with by
     it prior to or at the time the advance is made.

          7.4 Opinion of Counsel.  The Borrower  shall have delivered an opinion
     of its  counsel,  dated  the  date  of this  Agreement,  and  upon  request
     supplemental  opinions dated the date of the advance, in form and substance
     reasonably satisfactory to the Bank.

          7.5 Documents to be Delivered.  The Borrower  shall have  delivered to
     the Bank all security agreements,  reimbursement  agreements,  assignments,
     guarantees,  and any related documents necessary or desirable in connection
     with the  requirements  of  Article 5  hereof.  All  notes  evidencing  the
     Obligations shall have been delivered to the Bank at the time of the making
     of the respective loans.

          7.6 Certified  Resolutions.  Each of the Borrowers and the  Guarantors
     shall have delivered a certificate of its corporate  secretary  certifying,
     as of the  date of the  first  advance,  resolutions  duly  adopted  by its
     respective  Board of  Directors  authorizing  the  execution,  delivery and
     performance of this Agreement, or in the case of Guarantors, its respective
     guarantee, and all related documents and agreements and the consummation of
     the transactions  contemplated  hereby,  which  resolutions shall remain in
     full force and effect so long as any of the  Obligations are outstanding or
     any commitment to lend exists under this Agreement.

          7.7 Fees and Taxes.  The  Borrower  shall  have paid all filing  fees,
     taxes, and assessments  related to the borrowings and the perfection of any
     interests in collateral security required hereunder.

          7.8 Insurance. The Borrower shall have delivered evidence satisfactory
     to the Bank of the existence of insurance required hereby.
<PAGE>
          7.9 Organizational Documents. The Borrower shall have delivered to the
     Bank copies of its  then-effective  Certificate of Incorporation,  By-laws,
     d/b/a certificates, and other organizational documents and instruments, and
     upon request of the Bank, a written  certificate  that such  documents  and
     instruments  have not been  changed  or amended  since the last  advance to
     Borrower pursuant to the terms of this Agreement.

          7.10 Other  Documents  and  Agreements.  On or before the date of this
     Agreement,   the  Borrower  shall  have  delivered  such  other  documents,
     instruments,  and  agreements as the Bank and its legal counsel may require
     in connection with the transactions contemplated hereby.

          7.11  Certificates  of Good  Standing.  On or before  the date of this
     Agreement the Borrower  shall have  delivered to the Bank  certificates  of
     good standing from appropriate  state officials to the effect that the each
     of  the  Borrowers  and  each  Domestic  Subsidiary  that  owns  a  Foreign
     Subsidiary  is in good standing in the state of its formation as well as in
     all  other  states  in which  qualification  is  necessary  for each of the
     Borrowers and such Domestic  Subsidiaries  to carry on its business in such
     states.

          7.12 Appraisal. The Borrower shall have delivered to the Bank prior to
     the making of the Mortgage  Note an appraisal in form  satisfactory  to the
     Bank,  prepared by appraisers  satisfactory  to the Bank,  showing that the
     principal  amount of the Mortgage Note will not exceed eighty percent (80%)
     of the fair market value of the Mortgaged Property.

          7.13 Title  Insurance.  Prior to the making of the Mortgage  Loan, the
     Borrower  shall  have  delivered  to the  Bank's  legal  counsel an updated
     Abstract  of Title and shall have  delivered  title  insurance  in the face
     amount of the Mortgage Loan, with all title exceptions being subject to the
     approval of the Bank's attorneys.

          7.14 Survey.  Prior to the making of the Mortgage  Loan,  the Borrower
     shall have  delivered to the Bank a survey  prepared by a  registered  land
     surveyor,  showing all  encroachments  or easements  across property lines.
     Those  encumbrances  not  acceptable  to the Bank and its  counsel  must be
     removed.  Said survey is to be approved by,  satisfactory to, and certified
     to the Bank, the Bank's attorneys, and the title insurance company.

          7.15 Real Estate Taxes.  Prior to the making of the Mortgage Loan, the
     Borrower  must  provide  proof of payment of current  real estate taxes and
     assessments related to the Mortgaged  Property,  or payment of all payments
     due under any payment-in-lieu-of-tax agreements, if any.

          7.16  Environmental  Report.  The Borrower  shall have provided to the
     Bank an environmental  inspection report covering the Mortgaged Property in
     form  and  substance   satisfactory  to  the  Bank  prepared  by  engineers
     satisfactory to the Bank.
<PAGE>
ARTICLE 8 - AFFIRMATIVE COVENANTS OF BORROWER

          So long as any  Obligations  to the Bank shall be  outstanding or this
     Agreement remains in effect, unless the Bank otherwise consents in writing,
     the Borrower shall:

          8.1  Financial  Statements.  Furnish to the Bank as soon as available,
     but in no event later than one hundred  twenty  (120) days after the end of
     each of its fiscal years, copies of its annual report containing its annual
     financial  statements  audited by and with an  unqualified  opinion from an
     independent  certified  public  accountant  satisfactory  to the Bank. Said
     financial statements shall be accompanied by (i) copies of its Form 10K for
     the  respective  year,  (ii) a schedule  showing  computation  of financial
     covenants, (iii) a copy of any management letter prepared by the Borrower's
     accountants,  and (iv) a certificate of the Chief Financial  Officer or the
     Chief  Accounting  Officer of the  Borrower  to the effect that no Event of
     Default has occurred and no condition exists which with the passage of time
     or the giving of notice would constitute an Event of Default.

          The   Borrower   also  shall   furnish  to  the  Bank  copies  of  its
     consolidating  quarterly  financial  statements  and Form 10Q not more than
     fifty (50) days after the close of each  quarter of its fiscal  year.  Said
     statements  shall be accompanied by (i) a schedule  showing  computation of
     financial covenants,  and (ii) a certificate of the Chief Financial Officer
     or the Chief Accounting Officer of the Borrower to the effect that no Event
     of Default has occurred  and no condition  exists which with the passage of
     time or the giving of notice would constitute an Event of Default.

          The Borrower shall provide to the Bank interim  financial  statements,
     if any, prepared by the Borrower's independent accountants.

          8.2  Other  Reports  and  Inspections.  Furnish  to the Bank an annual
     budget  within 30 days of the  commencement  of any fiscal  year,  and such
     additional  information,  reports, or financial statements as the Bank may,
     from time to time, reasonably request.

          The Borrower shall permit any person designated by the Bank to inspect
     the property,  assets,  and books of the Borrower at reasonable  times and,
     prior to an Event of Default, upon reasonable notice, and shall discuss its
     affairs, finances, and accounts at reasonable times with the Bank from time
     to time as often as may be reasonably requested.

          8.3 Taxes.  Pay and  discharge  all taxes,  assessments,  levies,  and
     governmental charges upon the Borrower,  its income and property,  prior to
     the date on which penalties are attached thereto;  provided,  however, that
     the Borrower may in good faith contest any such taxes, assessments, levies,
     or charges so long as such  contest is  diligently  pursued  and no lien or
     execution  exists or is levied against any of Borrower's  assets related to
     the contested items and so long as Borrower maintains all reserves required
     by GAAP.
<PAGE>
          8.4 Insurance.  Maintain or cause to be maintained insurance, of kinds
     and  in  amounts  satisfactory  to the  Bank,  with  responsible  insurance
     companies  on all of its real and personal  properties  in such amounts and
     against such risks as are prudent,  including but not limited to, full-risk
     extended  coverage  hazard  insurance to the full  insurable  value of real
     property  (co-insurance  not being  permitted  without  the  prior  written
     consent of the Bank),  all-risk  coverage for personal  property,  business
     interruption or loss of rents coverage,  worker's  compensation  insurance,
     and comprehensive  general liability and products liability insurance.  The
     Borrower  also shall  maintain  flood  insurance  covering  any of its real
     properties  located in flood zones. The Borrower shall provide to the Bank,
     no less often  than  annually  and upon its  request,  a detailed  list and
     evidence  satisfactory  to the Bank of its insurance  carriers and coverage
     and shall  obtain  such  additional  insurance  as the Bank may  reasonably
     request. Hazard insurance policies for real property shall name the Bank as
     mortgagee,  and for personalty,  additional  insured and loss payee, as its
     interests may appear.  All policies  shall provide for at least thirty (30)
     days' prior notice of cancellation to the Bank.

          8.5 Existence.  Cause to be done all things  necessary to preserve and
     to keep in full force and effect its existence,  rights, and franchises and
     to comply in all material  respects with all valid laws and regulations now
     in effect or hereafter promulgated by any properly constituted governmental
     authority having jurisdiction.

          8.6  Maintenance  of  Properties.  At all  times  maintain,  preserve,
     protect,  and keep its property used or useful in conducting  its business,
     in good repair,  working order,  and condition and, from time to time, make
     all needful and proper repairs, renewals,  replacements,  betterments,  and
     improvements  thereto,  so that the business carried on may be properly and
     advantageously conducted at all times.

          8.7 Material  Changes,  Judgments.  Notify the Bank immediately of any
     material  adverse change in the financial  condition of the Borrower and of
     the  filing  of  any  suits,   judgments,  or  liens  which,  if  adversely
     determined,  could  have a  material  adverse  effect  on the  business  or
     financial  condition of the  Borrower.  The Borrower  also shall notify the
     Bank  immediately of any change in the name,  identity,  or  organizational
     structure  of the  Borrower,  or any  change  in any  equity  or  ownership
     interest in Radionics, the Guarantors, or any Foreign Subsidiary.

          8.8  ERISA  Compliance.  Comply  in all  material  respects  with  the
     provisions of ERISA and regulations and interpretations related thereto.

          8.9  Franchises/Permits/Laws.  Preserve  and  keep in full  force  and
     effect  all  franchises,  permits,  licenses,  and other  authority  as are
     necessary  to enable it to conduct its  business as being  conducted on the
     date of this  Agreement and comply in all material  respects with all laws,
     regulations, and requirements now in effect or hereafter promulgated by any
     properly constituted governmental authority having jurisdiction over it.

          8.10  Payments.  Make  all  payments  as and  when  required  by  this
     Agreement  and the  notes  and other  agreements  related  hereto or to the
     Obligations.
<PAGE>
          8.11 Deposits/Bank Services.  Detection,  and to the extent practical,
     Radionics,  shall maintain all of its main depository  accounts at the Bank
     and shall obtain its cash management services from the Bank.

          8.12  Amendments.  Give the Bank  written  notice of an  amendment  or
     modification  to  the  Certificate  of  Incorporation  or  other  governing
     documents or agreements of either Borrower.

          8.13  Subsidiaries.  Cause each  Subsidiary  to comply in all respects
     with the same  requirements  as are imposed  upon the  Borrower in Sections
     8.3, 8.4, 8.5, 8.6, 8.7, 8.8, and 8.9 of this Agreement.

ARTICLE 9 - NEGATIVE COVENANTS OF BORROWER

          So long as any  Obligations  shall be  outstanding,  or this Agreement
     shall remain in effect,  unless the Bank otherwise consents in writing, the
     Borrower shall not, directly or indirectly:

          9.1 Debt/Liens.  Create, incur, assume, or allow to exist, voluntarily
     or involuntarily,  any Debt, or any security interest,  assignment, pledge,
     lien or  other  encumbrance  for the  purpose  of  collateral  of any  kind
     (including the charge upon property  purchased under  conditional  sales or
     other  title  retention  agreements)  upon any of its  property  or assets,
     whether now owned or hereafter  acquired,  or become the general partner in
     any  partnership,  excluding only (i)  Obligations to and interests held by
     the Bank,  (ii) Debt  described in Schedule 9.1 attached  hereto and made a
     part  hereof,  (iii)  encumbrances  described  in  Schedule  5.1,  and (iv)
     obligations and interests to which the Bank consents in writing.

          9.2  Loans  and  Investments.  Make any  loan or  advance  to,  or any
     investment of any kind in, any person, firm, joint venture,  corporation or
     other entity whatsoever,  except (i) short-term investments in certificates
     of deposit of financial  institutions  and similar  investments made in the
     ordinary  course of  business,  and (ii) to the  extent  permitted  by this
     Agreement,  to or in  any  Subsidiary,  provided  however,  that  aggregate
     investments  and/or capital  contributions by the Borrower and its Domestic
     Subsidiaries in or to the Foreign  Subsidiaries (taken as a whole) shall in
     no event exceed $1,000,000 per year.

          9.3 Mergers,  Sales and  Acquisitions/Change  in Ownership  Interests.
     Enter into any merger or consolidation, or acquire all or substantially all
     the stock or other ownership interests or assets of any person, firm, joint
     venture,  corporation,  or other entity except for acquisition transactions
     involving the  expenditure  by the Borrower and its  Affiliates of not more
     than  $1,000,000  in total  consideration  in any one year or in any single
     transaction; or sell, lease, transfer, or otherwise dispose of any material
     portion of its assets except in the ordinary course of business.
<PAGE>
          The  Borrower  will not allow any  change in the  ownership,  legal or
     equitable,  of the shareholder or other equity interests in Radionics or in
     the  Subsidiaries  except  between or among the  Borrower  and the Domestic
     Subsidiaries.

          9.4 Amendments. Allow the amendment or modification of either of their
     Certificates of Incorporation,  By-laws,  or other governing  documents and
     agreements in any material respect without the prior written consent of the
     Bank.

          9.5 Compensation.  Compensate any person or entity,  including without
     limitation salaries,  bonuses,  consulting fees, or otherwise, in excess of
     amounts reasonably related to services rendered to the Borrower.

          9.6 Judgments. Allow to exist any judgments against Borrower in excess
     of $100,000 which are not fully covered by insurance or for which an appeal
     or other  proceeding  for the review  thereof shall not have been taken and
     for  which a stay of  execution  pending  such  appeal  shall not have been
     obtained.

          9.7 Margin  Securities.  Allow any proceeds of the  Obligations  to be
     used for the  purpose  of  carrying  any  Margin  Securities  as defined in
     Regulation U of the Board of Governors of the Federal Reserve.

          9.8 Tennessee  Assets.  Allow any of either of their respective assets
     to be  located  in the  State of  Tennessee  with a value in  excess of the
     dollar amount limitation of coverage by the respective  Borrower's Security
     Agreements related to Tennessee assets.

          9.9 Negative Pledge. Assign, transfer, pledge or otherwise encumber to
     or in favor of anyone other than the Bank any property,  real,  personal or
     intangible,  which the Borrower now or hereafter owns. Borrower will not at
     any time enter into any agreement  with anyone other than the Bank in which
     the Borrower agrees not to assign,  transfer,  pledge or otherwise encumber
     any  property,  real,  personal or  intangible,  which the  Borrower now or
     hereafter owns.

          9.10  Subsidiaries.  Cause each  Subsidiary  to comply in all respects
     with the same  requirements  as are imposed  upon the  Borrower in Sections
     9.1, 9.2, 9.3, 9.5, 9.6, 9.8 and 9.9 of this Agreement.


ARTICLE 10 - FINANCIAL COVENANTS

          The financial covenants set forth in Section 10.1, 10.2, 10.3 and 10.4
     shall be determined by  calculating  such covenant for the Borrower and its
     Subsidiaries on a consolidated basis and without  duplication in accordance
     with GAAP.

          So long as any  Obligations  to the Bank shall be  outstanding or this
     Agreement remains in effect, unless the Bank otherwise consents in writing,
     the Borrower, shall:
<PAGE>
          10.1 Minimum  Current  Ratio.  Maintain a minimum  Current Ratio of at
     least 2.0 to 1.0, as shown on each quarterly  financial  statement provided
     to the Bank.

          10.2  Minimum  Fixed Charge  Coverage.  Maintain a ratio of (a) EBITDA
     minus Distributions to (b) Fixed Charges, calculated for the quarter ending
     on the  measurement  date  plus the  fewer  of  either  (i) the last  three
     preceding  quarters,  or (ii) the number of quarters except the measurement
     date  quarter  that  have  ended  after  March  31,  1998,  as shown on the
     quarterly financial statements provided to the Bank, of at least 1.5 to 1.0
     for the quarter ending June 30, 1998 and thereafter.

          10.3  Maximum  Funded Debt  Ratio.  Maintain a ratio of Funded Debt to
     EBITDA,  calculated for the quarter ending on the measurement date plus the
     three preceding quarters, not exceeding:

          (a)  2.75  to 1.0  measured  commencing  September  30,  1998,  and on
     December 31, 1998,  March 31, 1999,  June 30, 1999,  September 30, 1999 and
     December 31, 1999 

          (b) 2.5 to 1.0  measured on March 31, 2000,  June 30, 2000,  September
     30, 2000, and December 31, 2000,
  
          (c) 2.25 to 1.0 measured on March 31, 2001,  June 30, 2001,  September
     30, 2001, and December 31, 2001, and

          (d) 2.0  measured  on March  31,  2002 and at the end of each  quarter
     thereafter.

          10.4 Minimum Tangible Net Worth. Maintain a minimum Tangible Net Worth
     equal to at least ninety  percent (90%) of the higher of Tangible Net Worth
     of the  Borrower  (a) as of the  date  of  this  Agreement,  and  (b) as of
     December 31, 1997, as shown on each quarterly  financial statement provided
     to the Bank. Such minimum Tangible Net Worth requirement shall be increased
     in each succeeding  fiscal year by an amount equal to seventy-five  percent
     (75%) of net  operating  income for the prior  fiscal year plus one hundred
     percent  (100%) of the net proceeds  from any sale of stock or other equity
     interests in the Borrower.

          10.5 Limitation on Foreign  Intercompany  Indebtedness.  Ensure at all
     times that aggregate  indebtedness of all Foreign Subsidiaries owing to the
     Borrower  and all  Domestic  Subsidiaries  at no time  exceeds by more than
     $29,900,000  the  aggregate  indebtedness  of the Borrower and all Domestic
     Subsidiaries owing to all Foreign Subsidiaries.

ARTICLE 11 - ENVIRONMENTAL MATTERS; INDEMNIFICATION

          11.1  Environmental  Representations.   The  Borrower  represents  and
     warrants that, to the best of Borrowers's  knowledge and except as shown on
     Schedule 11.1:

          (a)  Neither  the  Improvements  nor  any  property  adjacent  to  the
     Improvements  is  being  or has  been  used  for  the  storage,  treatment,
     generation, transportation, processing, handling, production or disposal of
     any  Hazardous  Substance or as a landfill or other waste  disposal site or
     for the  storage  of  petroleum  or  petroleum  based  products  except  in
     compliance with all Environmental Laws.
<PAGE>
          (b) Underground storage tanks are not and have not been located on the
     Improvements except in compliance with all Environmental Laws.

          (c) The soil, subsoil,  bedrock,  surface water and groundwater of the
     Improvements are free of any Hazardous Substances.

          (d) There has been no Release, nor is there the threat of a Release of
     any  Hazardous  Substance on, at or from the  Improvements  or any property
     adjacent  to or within the  immediate  vicinity of the  Improvements  which
     through soil,  subsoil,  bedrock,  surface water or  groundwater  migration
     could come to be located on the Improvements, and Borrower has not received
     any form of notice or inquiry from any federal, state or local governmental
     agency or authority, any operator, tenant, subtenant,  licensee or occupant
     of the  Improvements  or any property  adjacent to or within the  immediate
     vicinity of the  Improvements  or any other person with regard to a Release
     or the threat of a Release of any  Hazardous  Substance  on, at or from the
     Improvements or any property adjacent to the Improvements.

          (e)  All  Environmental  Permits  relating  to the  Borrower  and  the
     Improvements have been obtained and are in full force and effect.

          (f) No event has occurred with respect to the Improvements which, with
     the passage of time or the giving of notice,  or both,  would  constitute a
     violation of any applicable  Environmental Law or  non-compliance  with any
     Environmental Permit.

          (g) There  are no  agreements,  consent  orders,  decrees,  judgments,
     license or permit  conditions or other orders or directives of any federal,
     state or local  court,  governmental  agency or  authority  relating to the
     past,  present or future  ownership,  use,  operation,  sale,  transfer  or
     conveyance  of the  Improvements  which  require  any change in the present
     condition  of  the  Improvements  or  any  work,   repairs,   construction,
     containment,  clean up, investigations,  studies, removal or other remedial
     action or capital expenditures with respect to the Improvements.

          (h) There are no actions,  suits,  claims or  proceedings,  pending or
     threatened,  which could cause the  incurrence  of expenses or costs of any
     name or  description  or  which  seek  money  damages,  injunctive  relief,
     remedial  action or any other remedy that arise out of, relate to or result
     from (i) a violation or alleged  violation of any applicable  Environmental
     Law or  non-compliance  or alleged  non-compliance  with any  Environmental
     Permit,  (ii) the presence of any  Hazardous  Substance or a Release or the
     threat  of a  Release  of  any  Hazardous  Substance  on,  at or  from  the
     Improvements or any property  adjacent to or within the immediate  vicinity
     of the  Improvements  or (iii) human  exposure to any Hazardous  Substance,
     noises,  vibrations  or nuisances  of whatever  kind to the extent the same
     arise  from  the  condition  of the  Improvements  or the  ownership,  use,
     operation,   sale,  transfer  or  conveyance  thereof.  
<PAGE>
          11.2 Environmental  Covenants.  The Borrower covenants and agrees with
     the Bank that, so long as this  Agreement  remains in effect,  the Borrower
     shall:

          (a) Comply with, and shall cause all operators,  tenants,  subtenants,
     licensees and occupants of the  Improvements  to comply with all applicable
     Environmental  Laws and shall obtain and comply  with,  and shall cause all
     operators, tenants, subtenants, licensees and occupants of the Improvements
     to obtain and comply with, all Environmental Permits.

          (b) Not  cause or  permit  any  change  to be made in the  present  or
     intended  use of the  Improvements  which would (i) violate any  applicable
     Environmental  Law, (ii) constitute  non-compliance  with any Environmental
     Permit or (iii) materially  increase the risk of a Release of any Hazardous
     Substance.

          (c) Promptly  provide Bank with a copy of all  notifications  which it
     gives or receives with respect to any past or present Release or the threat
     of a Release of any Hazardous  Substance on, at or from the Improvements or
     any property adjacent to the Improvements.

          (d) Undertake and complete all investigations,  studies,  sampling and
     testing  and all  removal  and other  remedial  actions  required by law to
     contain,  remove and clean up all Hazardous  Substances that are determined
     to be  present  at the  Improvements  in  accordance  with  all  applicable
     Environmental Laws and all Environmental Permits.

          (e) At all times allow the Bank and its officers,  employees,  agents,
     representatives,  contractors and  subcontractors  reasonable  access after
     reasonable   prior  notice  to  the   Improvements   for  the  purposes  of
     ascertaining  site conditions,  including,  but not limited to,  subsurface
     conditions.

          (f) Deliver promptly to the Bank: (i) copies of any documents received
     from the  United  States  Environmental  Protection  Agency,  or any state,
     county  or  municipal   environmental  or  health  agency   concerning  the
     Borrower's operations or the Improvements; and (ii) copies of any documents
     submitted by the  Borrower to the United  States  Environmental  Protection
     Agency or any state,  county or municipal  environmental  or health  agency
     concerning its operations or the Improvements.
<PAGE>
          (g) If at any  time  the  Bank  obtains  any  reasonable  evidence  or
     information which suggests that a material potential  environmental problem
     may  exist  at the  Improvements,  the  Bank  may  require  that a full  or
     supplemental  environmental inspection and audit report with respect to the
     Improvements  of a  scope  and  level  of  detail  satisfactory  to Bank be
     prepared by an environmental  engineer or other qualified person acceptable
     to the Bank at  Borrower's  expense.  Such  audit may  include  a  physical
     inspection  of the  Improvements,  a  visual  inspection  of  any  property
     adjacent to or within the immediate vicinity of the Improvements, personnel
     interviews and a review of all Environmental Permits. If the Bank requires,
     such  inspection  shall also  include a records  search  and/or  subsurface
     testing for the  presence of  Hazardous  Substances  in the soil,  subsoil,
     bedrock,  surface water and/or groundwater.  If such audit report indicates
     the  presence of any  Hazardous  Substance  or a Release or the threat of a
     Release  of any  Hazardous  Substance  on,  at or  from  the  Improvements,
     Borrower shall promptly  undertake and diligently  pursue to completion all
     necessary,  appropriate and legally authorized investigative,  containment,
     removal,  clean up and other remedial actions, using methods recommended by
     the engineer or other person who prepared said audit report and  acceptable
     to the appropriate federal, state and local agencies or authorities.

          11.3  Indemnity.  The Borrower agrees to indemnify,  defend,  and hold
     harmless  the  Bank  from  and  against  any and all  liabilities,  claims,
     damages,  penalties,  expenditures,  losses, or charges, including, but not
     limited to, all costs of investigation,  monitoring,  legal representation,
     remedial response,  removal,  restoration or permit acquisition of any kind
     whatsoever,  which may now or in the future be undertaken,  suffered, paid,
     awarded,  assessed,  or otherwise incurred by the Bank (or any other person
     or entity  affiliated  with the Bank or representing or acting for the Bank
     or at the  Bank's  behest,  or with a claim on the Bank or to whom the Bank
     has liability or  responsibility  of any sort related to this Section 11.3)
     relating  to,  resulting  from  or  arising  out  of  (a)  the  use  of the
     Improvements  for  the  storage,  treatment,  generation,   transportation,
     processing,  handling, production or disposal of any Hazardous Substance or
     as a  landfill  or other  waste  disposal  site,  (b) the  presence  of any
     Hazardous  Substance  or a  Release  or  the  threat  of a  Release  of any
     Hazardous  Substance  on, at or from the  Improvements,  (c) the failure to
     promptly  undertake  and  diligently  pursue to completion  all  necessary,
     appropriate and legally  authorized  investigative,  containment,  removal,
     clean up and other remedial actions with respect to a Release or the threat
     of a Release of any Hazardous  Substance  on, at or from the  Improvements,
     (d) human  exposure  to any  Hazardous  Substance,  noises,  vibrations  or
     nuisances of whatever  kind to the extent the same arise from the condition
     of the Improvements or the ownership,  use,  operation,  sale,  transfer or
     conveyance  thereof,  (e) a violation of any applicable  Environmental Law,
     (f)  non-compliance  with  any  Environmental  Permit  or  (g)  a  material
     misrepresentation  or  inaccuracy  in any  representation  or warranty or a
     material  breach of or failure to perform any covenant  made by Borrower in
     this  Agreement.  Such costs or other  liabilities  incurred by the Bank or
     other  entity  described  in this  Section 11.3 shall be deemed to include,
     without limitation, any sums which the Bank deems it necessary or desirable
     to expend to protect its security interests and liens.
<PAGE>
          11.4 No  Limitation.  The liability of Borrower  under this Article 11
     shall in no way be limited, abridged, impaired or otherwise affected by (a)
     any  amendment or  modification  of this  Agreement  or any other  document
     relating  to the  Obligations  by or for the  benefit  of  Borrower  or any
     subsequent   owner  of  the   Improvements   except  for  an  amendment  or
     modification  which expressly refers to this Article 11, (b) any extensions
     of time for payment or performance  required by this Agreement or any other
     document  relating to the  Obligations,  (c) the release of  Borrower,  any
     guarantor or any other person from the  performance or observance of any of
     the agreements,  covenants, terms or conditions contained in this Agreement
     or any other  document  relating to the  Obligations  by  operation of law,
     Bank's voluntary act or otherwise,  (d) the invalidity or  unenforceability
     of any of the terms of provisions of this  Agreement or any other  document
     relating to the  Obligations,  (e) any exculpatory  provision  contained in
     this Agreement or any other document  relating to the Obligations  limiting
     Bank's  recourse to  property  encumbered  by any  mortgage or to any other
     security  or  limiting  Bank's  rights  to a  deficiency  judgment  against
     Borrower, (f) any applicable statute of limitations,  (g) any investigation
     or inquiry  conducted by or on the behalf of Bank or any information  which
     Bank may have or obtain with  respect to the  environmental  or  ecological
     condition of the Improvements,  (h) the sale,  assignment or foreclosure of
     any interest in collateral for the Obligations,  (i) the sale,  transfer or
     conveyance  of all or part of the  Improvements,  (j) the  dissolution  and
     liquidation  of  Borrower,  (k)  the  death  or  legal  incapacity  of  any
     individual,  (l) the release or discharge, in whole or in part, of Borrower
     in any bankruptcy, insolvency,  reorganization,  arrangement, readjustment,
     composition,   liquidation  or  similar   proceeding,   or  (m)  any  other
     circumstances which might otherwise constitute a legal or equitable release
     or discharge of Borrower, in whole or in part.

          11.5  Survival.  Notwithstanding  anything to the  contrary  contained
     herein,  the Borrower's  liability and obligations under Section 11.4 shall
     survive the discharge,  satisfaction or assignment of this Agreement by the
     Bank and the payment in full of all of the Obligations.

          11.6   Investigations.   If  the  Borrower  defaults  on  any  of  its
     Obligations pursuant to this Agreement or any other Loan Document, the Bank
     or its  designee  shall  have the  right,  upon  reasonable  notice  to the
     Borrower,   to  enter  upon  the   Improvements  and  conduct  such  tests,
     investigation  and sampling,  including but not limited to  installation of
     monitoring  wells,  as  shall  be  reasonably  necessary  for  the  Bank to
     determine whether any disposal of Hazardous  Substances has occurred on, at
     or near the Improvements.  The costs of all such tests,  investigations and
     samplings  shall be considered as  additional  indebtedness  secured by all
     collateral for the Obligations and shall become immediately due and payable
     without notice and with interest  thereon at highest rate then borne by any
     of the Obligations.
<PAGE>
          11.7 No Warranty Regarding  Information.  The Borrower agrees that the
     Bank shall not be liable in any way for the completeness or accuracy of any
     Environmental  Report or the information  contained  therein.  The Borrower
     further  agrees that the Bank has no duty to warn the Borrower or any other
     person or entity about any actual or potential environmental  contamination
     or other problem that may have become  apparent or will become  apparent to
     the Bank.

ARTICLE 12 - DEFAULTS

          12.1 Defaults.  The following  events  (hereinafter  called "Events of
     Default") shall  constitute  defaults under this Agreement.  Such Events of
     Default shall be without  prejudice to the Bank's rights to demand  payment
     in full of Obligations payable on demand, as specified in this Agreement or
     the notes relating to such Obligations, at any time.

          a. Nonpayment. Failure of the Borrower to make any payment of any type
     under the terms of the Loan  Documents  within ten (10) days after the same
     becomes due and payable.

          b.  Performance.  Failure of the Borrower or any Subsidiary to observe
     or perform any other  condition,  covenant  or term of the Loan  Documents;
     provided,  however, except with respect to Sections 8.1 and 8.4 and Article
     10 of this  Agreement,  if such failure is  susceptible to cure an Event of
     Default shall not occur unless such failure is not cured within thirty (30)
     days  after the Bank  gives the  Borrower  or the  Subsidiary  respectively
     notice of same.

          c. Other  Obligations.  Failure of the Borrower or any  Subsidiary  to
     observe  or perform  any other  condition,  covenant,  or term of any other
     agreement with the Bank after any  applicable  cure or grace period related
     thereto,  or default by the Borrower or any Subsidiary  under any agreement
     involving  Debt or any other  material  agreement  with any third person or
     entity.

          d. Representations. (i) failure of any representation or warranty made
     by the Borrower or any  Guarantor in  connection  with the execution of the
     Loan Documents,  or any  certificate of officers  pursuant  thereto,  to be
     truthful,  accurate  or correct  in all  material  respects,  or (ii) after
     fifteen (15) days notice and failure to cure, failure of any representation
     or warranty made by the Borrower or any  Guarantor in  connection  with the
     performance  of  the  Loan  Documents   after  the  closing  date,  or  any
     certificate  of  officers  pursuant  thereto to be  truthful,  accurate  or
     correct in all material respects.

          e. Financial  Difficulties.  Financial difficulties of the Borrower or
     any Guarantor as evidenced by:

          (i) any  admission in writing of inability to pay debts as they become
     due; or

          (ii) the filing of a voluntary or involuntary  petition in bankruptcy,
     or under any chapters of the Bankruptcy Code, or under any federal or state
     statute providing for the relief of debtors; or

          (iii) making an assignment for the benefit of creditors; or

          (iv) consenting to the appointment of a trustee or receiver for all or
     a major part of any of its property; or

          (v) the entry of a court order  appointing a receiver or a trustee for
     all or a major part of its property; or

          (vi) the occurrence of any event,  action,  or transaction  that could
     give  rise to a lien or  encumbrance  on the  assets of the  Borrower  as a
     result of application of relevant provisions of ERISA.
<PAGE>
          f. Material  Change.  After ten (10) days notice to the Borrower,  any
     condition by reason of which the Bank  reasonably  believes the  Borrower's
     ability to timely repay any Obligations to the Bank is impaired,  including
     without  limitation by reason of material or reasonably  projected material
     change in Borrower's  business or  operations,  or in any factor  affecting
     Borrower's  business or  operations,  or regarding any other  obligation or
     agreement of  Borrower,  or in the  financial  condition of Borrower or its
     Subsidiaries  taken as a whole,  or in the  collateral  for the  Borrower's
     Obligations.

          12.2 Remedies.  If any one or more Events of Default listed in Section
     12.1 (e)(i)-(v)  occur,  (a) any further  commitments or obligations of the
     Bank  shall be deemed to be  automatically  and  without  need for  further
     action  terminated,  and (b) all  Obligations  of the Borrower to the Bank,
     automatically  and without need for further action,  shall become forthwith
     due and payable without  presentment,  demand,  protest, or other notice of
     any kind,  all of which are  hereby  expressly  waived.  If any one or more
     Events of Default other than those listed in Section 12.1 (e)(i)-(v) occur,
     the Bank may, at its option,  take either or both of the following  actions
     at the same or different  times:  (a) terminate any further  commitments or
     obligations of the Bank, and (b) declare all Obligations of the Borrower to
     the  Bank,  automatically  and  without  need  for  further  action,  to be
     forthwith due and payable without  presentment,  demand,  protest, or other
     notice of any kind, all of which are hereby expressly waived.

          In case any such  Events of  Default  shall  occur,  the Bank shall be
     entitled to recover  judgment  against the Borrower for all  Obligations of
     the Borrower to the Bank either before, or after, or during the pendency of
     any proceedings for the enforcement, of any security interests,  mortgages,
     pledges,  or guarantees  and, in the event of realization of any funds from
     any security or  guarantee  and  application  thereof to the payment of the
     Obligations  due,  the Bank shall be  entitled  to  enforce  payment of and
     recover  judgment  for  all  amounts  remaining  due  and  unpaid  on  such
     Obligations.  The Bank shall be  entitled  to  exercise  any other legal or
     equitable  right which it may have,  and may proceed to protect and enforce
     its rights by any other appropriate  proceedings,  including action for the
     specific  performance  of any  covenant  or  agreement  contained  in  this
     Agreement and other agreements held by the Bank.

          After any Event of  Default,  the Bank may  require  the  Borrower  to
     deliver cash  collateral  to the Bank,  together  with  agreements  related
     thereto satisfactory to the Bank in its sole discretion, in an amount equal
     to the aggregate undrawn outstanding amount of all letters of credit issued
     pursuant to Section 2.8 of this Agreement.
<PAGE>
ARTICLE 13 - MISCELLANEOUS

          13.1  Waiver.  No delay or failure of the Bank to exercise  any right,
     remedy,  power or privilege hereunder shall impair the same or be construed
     to be a waiver of the same or of any Event of  Default  or an  acquiescence
     therein.  No single or  partial  exercise  of any right,  remedy,  power or
     privilege shall preclude other or further exercise thereof by the Bank. All
     rights,  remedies,  powers,  and privileges  herein conferred upon the Bank
     shall be deemed cumulative and not exclusive of any others available.

          13.2 Survival of  Representations.  All representations and warranties
     contained herein shall survive the execution and delivery of this Agreement
     and the execution and delivery of other agreements hereunder.

          13.3 Additional  Security/Setoff.  The Borrower and Guarantors  hereby
     grant  to the  Bank a lien,  security  interest,  and  right  of set off as
     security  for the  Obligations  upon and  against  all  deposits,  credits,
     collateral  and  property,  now or  hereafter in the  possession,  custody,
     safekeeping  or control of Bank or any  entity  under the  control of Fleet
     Financial  Group,  Inc.,  or in transit to any of them. At any time without
     demand or  notice,  the Bank may set off the same or any part  thereof  and
     apply the same to any  liability or  obligation  of Borrower or  Guarantors
     even  though  unmatured  and  regardless  of  the  adequacy  of  any  other
     collateral securing the Obligations.  Any and all rights to require Bank to
     exercise its rights or remedies with respect to any other  collateral which
     secures  the  Obligations,  prior to  exercising  its right of set off with
     respect to such  deposits,  credits,  or other  property of the Borrower or
     Guarantors are hereby knowingly, voluntarily, and irrevocably waived.

          13.4  Notices.  Any notice or demand  upon any party  hereto  shall be
     deemed to have been  sufficiently  given or served for all purposes  hereof
     when delivered in person or by nationally recognized overnight courier with
     receipt  requested,  or two Business Days after it is mailed certified mail
     postage prepaid, return receipt requested, addressed as follows:


            If to Bank:       Fleet National Bank
                                    One East Avenue
                                    Rochester, New York 14638
                                    Attention: Corporate Banking Department
                                               Martin K. Birmingham


            If to Borrower:   Detection Systems, Inc.
                                    130 Perinton Parkway
                                    Fairport, New York 14450
                                    Attention: President

Any party may change, by notice in writing to the other parties,  the address to
which notices to it shall be sent.
<PAGE>
          13.5 Entire  Agreement.  This Agreement and the documents  referred to
     herein embody the entire agreement and understanding  among the parties and
     supersede all prior agreements and  understandings  relating to the subject
     matter  hereof. This Agreement shall not be changed or amended without the
     written  agreement  of all parties  hereto.  This  Agreement  embodies  all
     commitments  to lend between the Bank and the Borrower and  supersedes  any
     prior commitments.

          13.6  Parties  in  Interest.  All the  terms  and  provisions  of this
     Agreement  shall  inure  to  the  benefit  of and be  binding  upon  and be
     enforceable by the parties and their respective  successors and assigns and
     shall  inure to the  benefit of and be  enforceable  by any holder of notes
     executed  hereunder.  Upon any transfer of any  Obligation  or any interest
     therein the Bank may deliver or otherwise  transfer or assign to the holder
     any  collateral  or  guarantees  for the  Obligation,  which  holder  shall
     thereupon have all the rights of the Bank.

          13.7  Business  Days.  All Loan  Documents  shall be  governed  by the
     Modified  Following  Business  Day  Convention,  but any  extension of time
     shall, in each such case, be included in the computation of any interest or
     fees.

          13.8 Oral and Telecopy  Requests.  As a  convenience  to the Borrower,
     Borrower  hereby  authorizes  the Bank to rely  upon  requests  made by the
     Borrower  or its  employees  in writing or by  telecopy,  and to treat such
     requests  as if they  were  made in a writing  delivered  to the Bank.  Any
     advance of funds made by the Bank  pursuant  to any such  request  shall be
     deemed to be authorized by the Borrower unless immediately repaid in full.

          13.9 Severability. In the event that any one or more of the provisions
     contained in this Agreement or any other agreement,  document, or guarantee
     related  hereto  shall,  for  any  reason,  be  held  invalid,  illegal  or
     unenforceable   in   any   respect,   such   invalidity,    illegality   or
     unenforceability  shall not affect any other provision of this Agreement or
     such other agreement, document, or guarantee.

          13.10  Governing  Law.  This  Agreement  and the notes and  agreements
     hereunder,  together with all of the rights and  obligations of the parties
     hereto,  shall be construed,  governed and enforced in accordance  with the
     laws  of the  State  of New  York  without  regard  to  conflicts  of  laws
     principles.

          13.11  Participations;  Assignments.  All the terms and  provisions of
     this  Agreement  shall inure to the  benefit of and be binding  upon and be
     enforceable by the parties and their respective  successors and assigns and
     shall  inure to the  benefit of and be  enforceable  by any holder of notes
     executed hereunder.

          Bank may at any time pledge all or any portion of its rights under the
     Loan   Documents,   including  any  portion  of  any  note  evidencing  the
     Obligations, to any of the twelve (12) Federal Reserve Banks.
<PAGE>
          The Bank shall have the unrestricted right at any time or from time to
     time, and without Borrower's or any Guarantor's  consent,  to assign all or
     any portion of its rights and obligations hereunder to one or more banks or
     other financial institutions (each an "Assignee"), and Borrower agrees that
     it shall execute,  or cause to be executed,  and shall cause each Guarantor
     to execute,  such documents,  including without  limitation,  amendments to
     this  Agreement  and to any other  Loan  Documents,  as the Bank shall deem
     necessary to effect the foregoing.  In addition, at the request of the Bank
     and any such  Assignee,  Borrower  shall  issue one or more new  promissory
     notes, as applicable, to any such Assignee and, if Bank has retained any of
     its rights and obligations  hereunder  following such assignment,  to Bank,
     which new promissory  notes shall be issued in  replacement  of, but not in
     discharge of, the liability  evidenced by the promissory  note held by Bank
     prior to such  assignment  and shall  reflect the amount of the  respective
     commitments and loans held by such Assignee and Bank after giving effect to
     such assignment.  Upon the execution and delivery of appropriate assignment
     documentation,  amendments, and any other documentation required by Bank in
     connection  with  such  assignment,  and the  payment  by  Assignee  of the
     purchase price agreed to by Bank and such Assignee,  such Assignee shall be
     a party to this Agreement and shall have all of the rights and  obligations
     of the Bank hereunder  (and under any and all other Loan  Documents) to the
     extent  that such  rights and  obligations  have been  assigned by the Bank
     pursuant  to  the  assignment  documentation  between  the  Bank  and  such
     Assignee,  and Bank shall be released  from its  obligations  hereunder and
     thereunder to a corresponding extent.

          The Bank shall have the  unrestricted  right at any time and from time
     to time, and without the consent of or notice to Borrower or Guarantor,  to
     grant  to one or  more  banks  or  other  financial  institutions  (each  a
     "Participant")   participating  interests  in  Bank's  obligation  to  lend
     hereunder  and/or any or all of the  Obligations.  In the event of any such
     grant by Bank of a participating  interest to  Participant,  whether or not
     upon notice to Borrower,  Bank shall remain responsible for the performance
     of its obligations hereunder and Borrower shall continue to deal solely and
     directly  with  Bank in  connection  with  Bank's  rights  and  obligations
     hereunder.

          The  Bank may  furnish  any  information  concerning  Borrower  in its
     possession  from time to time to  prospective  Assignees and  Participants,
     provided  that the Bank shall  require  any such  prospective  Assignee  or
     Participant  to agree in writing to maintain  the  confidentiality  of such
     information.

          13.12 Clarification of Prior Agreements.  This Agreement clarifies and
     supersedes the Amended and Restated  Credit  Agreement dated as of June 24,
     1997 between the Bank and the Borrower,  and the credit facilities  related
     thereto.

          13.13 Jurisdiction/TRIAL BY JURY. Grantor consents to jurisdiction and
     service of process in the courts of the State of New York and in the courts
     of the United States having jurisdiction hereof. BORROWER AND BANK MUTUALLY
     HEREBY KNOWINGLY,  VOLUNTARILY AND INTENTIONALLY WAIVE THE RIGHT TO A TRIAL
     BY JURY IN RESPECT OF ANY CLAIM BASED  HEREON,  ARISING OUT OF, UNDER OR IN
     CONNECTION WITH THIS AGREEMENT OR ANY OTHER LOAN DOCUMENTS OR ANY COURSE OF
     CONDUCT,  COURSE OF  DEALINGS,  STATEMENTS  (WHETHER  VERBAL OR WRITTEN) OR
     ACTIONS OF ANY PARTY.  THIS WAIVER  CONSTITUTES A MATERIAL  INDUCEMENT  FOR
     BANK TO ACCEPT THIS AGREEMENT AND MAKE THE LOANS CONTEMPLATED HEREUNDER.
<PAGE>
          13.14 Loss or  Mutilation.  Upon receipt of an affidavit of an officer
     of Bank as to the  loss,  theft,  destruction,  or  mutilation  of any note
     evidencing any Obligation or any other Loan Document which is not of public
     record,  and,  in  the  case  of  any  such  loss,  theft,  destruction  or
     mutilation,  upon  surrender  and  cancellation  of such note or other Loan
     Document, Borrower will issue, in lieu thereof, a replacement note or other
     Loan Document in the same  principal  amount  thereof and otherwise of like
     tenor.

          13.15 Usury. All agreements  between  Borrower,any  Guarantor and Bank
     are hereby expressly limited so that in no contingency or event whatsoever,
     whether by reason of acceleration or maturity of the indebtedness evidenced
     hereby or otherwise, shall the amount paid or agreed to be paid to Bank for
     the use or the forbearance of the indebtedness  evidenced hereby exceed the
     maximum  permissible  under  applicable  law.  As  used  herein,  the  term
     "applicable  law"  shall  mean the law in  effect  as of the  date  hereof,
     provided,  however  that in the  event  there is a change  in the law which
     results in a higher  permissible rate of interest,  then the Loan Documents
     shall be governed by such new law as of its effective date. In this regard,
     it is  expressly  agreed that it is the intent of Borrower  and Bank in the
     execution,  delivery and acceptance of this Agreement to contract in strict
     compliance  with the laws of the  State  of New York  from  time to time in
     effect. If, under or from any circumstances whatsoever,  fulfillment of any
     provision hereof or of any of the Loan Documents at the time performance of
     such provision shall be due, shall involve  transcending  the limit of such
     validity  prescribed by applicable law, then the obligation to be fulfilled
     shall automatically be reduced to the limits of such validity, and if under
     or from any  circumstances  whatsoever Bank should ever receive as interest
     an amount  which would exceed the highest  lawful  rate,  such amount which
     would be  excessive  interest  shall be  applied  to the  reduction  of the
     principal balance evidenced hereby and not to the payment of interest. This
     provision  shall control every other  provision of all  agreements  between
     Borrower and Bank.

          13.16 Time of Payments.  In the event that any payment is due from the
     Borrower  under  this  Agreement  or any note,  instrument,  agreement,  or
     document  related  hereto,  such  payment  shall  be  made  in  immediately
     available  funds to the Bank at or before 2:00 p.m. on the  Business Day on
     which such payment is due.  Payments made after such time shall continue to
     bear interest until the next succeeding Business Day at the rates otherwise
     provided in this Agreement.
<PAGE>
          IN WITNESS  WHEREOF,  the parties have executed this  Agreement on the
     date first above written.

                                  FLEET NATIONAL BANK

                                  By: /s/Martin K. Birmingham, Vice President


                                  DETECTION SYSTEMS, INC.

                                  By: /s/Frank J. Ryan, Secretary & Treasurer

 
                                  RADIONICS, INC.

                                  By: /s/Frank J. Ryan, Secretary & Treasurer
<PAGE>

                               INDEX TO SCHEDULES

SCHEDULE 5.1      -     Liens and Encumbrances

SCHEDULE 6.1      -     Affiliates and Subsidiaries

SCHEDULE 6.4      -     Litigation

SCHEDULE 9.1      -     Obligations

SCHEDULE 11.1     -     Environmental Matters



                                INDEX TO EXHIBITS


EXHIBIT A         -     Revolving Line Note

EXHIBIT B         -     Mortgage Loan Note

EXHIBIT C         -     Term Loan Note
<PAGE>
                                  SCHEDULE 5.1
                             Liens and Encumbrances
<PAGE>

                                  SCHEDULE 6.1
                           Affiliates and Subsidiaries
<PAGE>

                                  SCHEDULE 6.4
                                   Litigation
<PAGE>

                                  SCHEDULE 9.1
                                   Obligations
<PAGE>

                                  SCHEDULE 11.1
                              Environmental Matters
<PAGE>

                    AMENDED AND RESTATED REVOLVING LINE NOTE

$17,000,000                                                   September 30, 1998
 
     Unless otherwise  expressly  provided herein, all capitalized terms in this
Amended and Restated  Revolving Line Note ("Revolving Line Note") shall have the
meanings  given to them in the Amended and Restated  Credit  Facility  Agreement
dated as of September 30, 1998,  between the undersigned  ("Borrower") and Fleet
National Bank (as successor to Fleet Bank,  "Bank"), as the same may be amended,
extended, replaced, or modified from time to time (the "Credit Agreement").

     This Revolving Line Note amends, replaces, and restates in its entirety the
Revolving  Line Note dated as of May 31,  1996,  as amended and  restated by the
Amended and Restated Revolving Line Note dated February 18, 1997, as amended and
restated by the Amended and  Restated  Revolving  Line Note dated June 24, 1997,
given by the Borrower in favor of the Bank.


     FOR VALUE RECEIVED, the Borrower, jointly and severally, hereby promises to
pay to the order of the Bank,  at any of its banking  offices,  or at such other
places  as Bank may  specify  in  writing  to  Borrower,  the  principal  sum of
Seventeen  Million  Dollars  ($17,000,000),  or if less,  the  aggregate  unpaid
principal amount of all advances made by Bank to Borrower. Bank shall maintain a
record of amounts of  principal  and interest  payable by Borrower  from time to
time,  and the records of Bank  maintained  in the  ordinary  course of business
shall be prima facie  evidence of the  existence  and amounts of the  Borrower's
obligations  recorded  therein.  In addition,  Bank may mail or deliver periodic
statements to Borrower  indicating the date and amount of each advance hereunder
(but any failure to do so shall not relieve  Borrower of the obligation to repay
any advance). Unless Borrower questions the accuracy of an entry on any periodic
statement  within fifteen  business days after such mailing or delivery by Bank,
Borrower  shall be deemed to have accepted and be obligated by the terms of each
such periodic statement as accurately  representing the advances  hereunder.  In
the  event of  transfer  of this  Revolving  Line  Note,  or if the  Bank  shall
otherwise deem it  appropriate,  Borrower  hereby  authorizes Bank to endorse on
this  Revolving  Line Note the amount of  advances  and  payments to reflect the
principal  balance  outstanding from time to time. Bank is hereby  authorized to
honor borrowing and other requests  received from purported  representatives  of
Borrower orally, by telecopy,  in writing, or otherwise.  Oral requests shall be
conclusively  presumed  to have been made by an  authorized  person  and  Bank's
crediting of Borrower's  account with the amount  requested  shall  conclusively
establish Borrower's obligation to repay the amount advanced.

     Interest. All outstanding amounts under this Revolving Line Note shall bear
interest  until  paid in full at the Base  Rate  plus the  Applicable  Base Rate
Margin.  Changes in the rate of interest  applicable to this Revolving Line Note
shall become effective  automatically  and without notice at the time of changes
in the Base Rate.
<PAGE>
     The  Borrower,  however,  at least three  business  days prior to each Rate
Change  Date  may  notify  the Bank of its  election  to have a  portion  of the
outstanding  principal  amount under this  Revolving Line Note (which must be at
least  $1,000,000  and must be an  increment of  $100,000)  bear  interest for a
one-month,  three-month, or six month period commencing on such Rate Change Date
at the LIBOR Rate plus the Applicable LIBOR Margin.

     Interest shall be calculated based on actual days elapsed divided by a year
of 360 days.  Interest shall continue to accrue after maturity,  including after
acceleration  and  judgment,  at the rate required by this  Revolving  Line Note
until this  Revolving  Line Note is paid in full.  The rate of  interest on this
Revolving  Line Note may be increased  under the  circumstances  provided in the
Credit  Agreement.  The right of Bank to receive such increased rate of interest
shall not constitute a waiver of any other right or remedy of Bank.

     Payments.  Payments of all accrued  interest under this Revolving Line Note
shall be due and payable on the first day of each month.

     All remaining  outstanding  principal and accrued interest shall be due and
payable in full on the Revolving Line Termination Date.

     All payments  shall be in lawful money of the United States in  immediately
available  funds.  Unless canceled in writing by Borrower,  Borrower  authorizes
Bank to debit its  accounts at Bank to make  payments  due  hereunder,  but such
authority  shall not relieve  Borrower of the obligation to assure that payments
are made when due.

     Late  Charge.  This  Revolving  Line Note is  subject  to the late  charges
provided in the Credit Agreement.

     Maximum Rate. All agreements between Borrower and Bank are hereby expressly
limited  so that in no  contingency  or event  whatsoever,  whether by reason of
acceleration  of maturity of the  indebtedness  evidenced  hereby or  otherwise,
shall  the  amount  paid  or  agreed  to be  paid  to  Bank  for  the use or the
forbearance of the indebtedness  evidenced hereby exceed the maximum permissible
under  applicable law. As used herein,  the term "applicable law" shall mean the
law in effect as of the date hereof provided, however that in the event there is
a change in the law which results in a higher permissible rate of interest, then
this Note shall be governed by such new law as of its  effective  date.  In this
regard,  it is  expressly  agreed that it the intent of Borrower and Bank in the
execution, delivery and acceptance of this Note to contract in strict compliance
with the laws of the State of New York from time to time in effect. If, under or
from any circumstances whatsoever, fulfillment of any provision hereof or of any
other documents  between the Borrower and the Bank at the time of performance of
such  provision  shall be due,  shall  involve  transcending  the  limit of such
validity prescribed by applicable law, then the obligation to be fulfilled shall
automatically  be reduced to the limits of such  validity,  and if under or from
circumstances  whatsoever  Bank should ever receive as interest and amount which
would  exceed the highest  lawful  rate,  such amount  which would be  excessive
interest  shall be applied to the reduction of the principal  balance  evidenced
hereby and not to the payment of interest.  This  provision  shall control every
other provision of all agreements between Borrower and Bank.

     Prepayment.  This Revolving  Line Note is freely  prepayable in whole or in
part at any time,  subject to payment of Break Costs, if any, as provided in the
Credit Agreement.

     Holidays.  If this Revolving Line Note or any payment hereunder becomes due
on a day not a Business Day, the due date of this Revolving Line Note or payment
shall be extended to the next succeeding  Business Day, but any interest or fees
shall be calculated based upon the actual time of payment.

     Events of Default.  At Bank's option, this Revolving Line Note shall become
immediately  due and  payable in full,  without  further  presentment,  protest,
notice, or demand, upon the happening of any Event of Default.

     Modification  of Terms.  The terms of this  Revolving  Line Note  cannot be
changed,  nor may this  Revolving  Line Note be  discharged in whole or in part,
except by a writing  executed by Bank. In the event that Bank demands or accepts
partial  payments of this Revolving Line Note,  such demand or acceptance  shall
not be deemed to  constitute  a waiver of the right to demand the entire  unpaid
balance of this  Revolving  Line Note at any time in  accordance  with the terms
hereof.  Any delay or omission by Bank in exercising any rights  hereunder shall
not operate as a waiver of such rights.

     Collection  Costs.  Borrower  on  demand  shall pay all  expenses  of Bank,
including  without  limitation  reasonable  attorneys'  fees, in connection with
enforcement and collection of this Revolving Line Note.

     Miscellaneous.  To the fullest extent  permissible by law,  Borrower waives
presentment,  demand for payment,  protest, notice of nonpayment,  and all other
demands or notices  otherwise  required by law in connection  with the delivery,
acceptance,  performance,  default,  or enforcement of this Revolving Line Note.
Borrower consents to extensions, postponements, indulgences, amendments to notes
and agreements,  substitutions or releases of collateral,  and  substitutions or
releases of other parties  primarily or secondarily  liable herefor,  and agrees
that none of the same shall affect  Borrower's  obligations under this Revolving
Line Note which shall be unconditional.

     Laws.  Borrower  agrees that this  Revolving Line Note shall be governed by
the laws of the State of New York.


                                  DETECTION SYSTEMS, INC.

                                  By: /s/Frank J. Ryan, Secretary & Treasurer


                                  RADIONICS, INC.

                                  By: /s/Frank J. Ryan, Secretary & Treasurer
<PAGE>

                                    EXHIBIT B

                     AMENDED AND RESTATED MORTGAGE LOAN NOTE


$[3,400,000 - to be updated with current balance]             September 30, 1998


     Unless otherwise  expressly  provided herein, all capitalized terms in this
Mortgage  Loan Note shall have the  meanings  given to them in the  Amended  and
Restated  Credit  Facility  Agreement dated as of September 30, 1998 between the
undersigned ("Detection"), Radionics, Inc. and Fleet National Bank (as successor
to Fleet Bank,  "Bank"),  as the same may be  amended,  extended,  replaced,  or
modified from time to time (the "Credit Agreement").

     This Amended and Restated Mortgage Loan Note evidences the same obligations
as evidenced by, and amends and restates in its entirety, the Mortgage Loan Note
dated May 31, 1996 in the original  principal  amount of $3,400,000 given by the
Borrower  to the Bank,  as amended and  restated  by the  Amended  and  Restated
Mortgage  Loan Note  dated June 24,  1997 in the  original  principal  amount of
$3,400,000, given by the Borrower to the Bank.

     FOR VALUE  RECEIVED,  Detection  hereby promises to pay to the order of the
Bank, at any of its banking offices, or at such other places as Bank may specify
in writing  to  Borrower,  the  principal  sum of [Three  Million  Four  Hundred
Thousand Dollars ($3,400,000)].

     Interest. Outstanding principal amounts under this Mortgage Loan Note shall
bear interest until paid in full at the Base Rate plus the Applicable  Base Rate
Margin.  Changes in the rate of interest  applicable  to this Mortgage Loan Note
shall become effective  automatically  and without notice at the time of changes
in the Base Rate.

     Detection,  however,  at least two business  days prior to each Rate Change
Date may notify the Bank of its  election  to have a portion of the  outstanding
principal  amount  under  this  Mortgage  Loan  Note  (which  must  be at  least
$1,000,000  and must be an increment of $100,000) bear interest for a one-month,
three-month,  or six month  period  commencing  on such Rate  Change Date at the
LIBOR Rate plus the Applicable LIBOR Margin.

     Interest shall be calculated based on actual days elapsed divided by a year
of 360 days.

     Interest  shall  continue to accrue after  maturity at the rate required by
this Mortgage Loan Note until this Mortgage Loan Note is paid in full.  The rate
of interest on this Mortgage Loan Note may be increased under the  circumstances
provided in the Credit  Agreement.  The right of Bank to receive such  increased
rate of interest  shall not  constitute a waiver of any other right or remedy of
Bank.
<PAGE>
     Payments.  Payments of all accrued  interest  under this Mortgage Loan Note
shall be due and payable on the first day of each month. In addition, commencing
on October 1,  1998,  principal  payments  of  $20,987.65  each shall be due and
payable on the first day of each month.

     All  Obligations  under and related to this Mortgage Loan Note shall be due
and payable in full on May 31, 2006.

     All payments  shall be in lawful money of the United States in  immediately
available funds. Unless canceled in writing by Detection,  Detection  authorizes
Bank to debit its  accounts at Bank to make  payments  due  hereunder,  but such
authority shall not relieve  Detection of the obligation to assure that payments
are made when due.

     Late  Charge.  This  Mortgage  Loan  Note is  subject  to the late  charges
provided in the Credit Agreement.

     Maximum Rate. All agreements between Borrower and Bank are hereby expressly
limited  so that in no  contingency  or event  whatsoever,  whether by reason of
acceleration  of maturity of the  indebtedness  evidenced  hereby or  otherwise,
shall  the  amount  paid  or  agreed  to be  paid  to  Bank  for  the use or the
forbearance of the indebtedness  evidenced hereby exceed the maximum permissible
under  applicable law. As used herein,  the term "applicable law" shall mean the
law in effect as of the date hereof provided, however that in the event there is
a change in the law which results in a higher permissible rate of interest, then
this Note shall be governed by such new law as of its  effective  date.  In this
regard,  it is  expressly  agreed that it the intent of Borrower and Bank in the
execution, delivery and acceptance of this Note to contract in strict compliance
with the laws of the State of New York from time to time in effect. If, under or
from any circumstances whatsoever, fulfillment of any provision hereof or of any
other documents  between the Borrower and the Bank at the time of performance of
such  provision  shall be due,  shall  involve  transcending  the  limit of such
validity prescribed by applicable law, then the obligation to be fulfilled shall
automatically  be reduced to the limits of such  validity,  and if under or from
circumstances  whatsoever  Bank should ever receive as interest and amount which
would  exceed the highest  lawful  rate,  such amount  which would be  excessive
interest  shall be applied to the reduction of the principal  balance  evidenced
hereby and not to the payment of interest.  This  provision  shall control every
other provision of all agreements between Borrower and Bank.

     Prepayment.  This  Mortgage  Loan Note is freely  prepayable in whole or in
part at any time,  subject to payment of Break Costs, if any, as provided in the
Credit Agreement.

     Holidays.  If this Mortgage Loan Note or any payment  hereunder becomes due
on a Saturday, Sunday or other holiday on which the Bank is authorized to close,
the due date of this Mortgage Loan Note or payment shall be extended to the next
succeeding business day, but any interest or fees shall be calculated based upon
the actual time of payment.
<PAGE>
     Events of Default.  At Bank's option,  this Mortgage Loan Note shall become
immediately due and payable in full upon the happening of any Event of Default.

     Modification  of Terms.  The  terms of this  Mortgage  Loan Note  cannot be
changed,  nor may this  Mortgage  Loan Note be  discharged  in whole or in part,
except by a writing  executed by Bank. In the event that Bank demands or accepts
partial payments of this Mortgage Loan Note, such demand or acceptance shall not
be deemed to  constitute  a waiver of the  right to  demand  the  entire  unpaid
balance  of this  Mortgage  Loan Note at any time in  accordance  with the terms
hereof.  Any delay or omission by Bank in exercising any rights  hereunder shall
not operate as a waiver of such rights.

     Collection  Costs.  Detection  on demand  shall pay all  expenses  of Bank,
including  without  limitation  reasonable  attorneys'  fees, in connection with
enforcement and collection of this Mortgage Loan Note.

     Miscellaneous.  To the fullest extent  permissible by law, Detection waives
presentment,  demand for payment, protest, notice of non-payment,  and all other
demands or notices  otherwise  required by law in connection  with the delivery,
acceptance,  performance,  default,  or  enforcement of this Mortgage Loan Note.
Detection  consents to  extensions,  postponements,  indulgences,  amendments to
notes and agreements, substitutions or releases of collateral, and substitutions
or releases of other parties primarily or secondarily liable herefor, and agrees
that none of the same shall affect  Detection's  obligations under this Mortgage
Loan Note which shall be unconditional.

     Laws.  Detection  agrees that this  Mortgage Loan Note shall be governed by
the laws of the State of New York.


                            DETECTION SYSTEMS, INC.

                            By: /s/Frank J. Ryan, Secretary & Treasurer

<PAGE>
                       AMENDED AND RESTATED TERM LOAN NOTE


$14,350,000                                                   September 30, 1998


     Unless otherwise  expressly  provided herein, all capitalized terms in this
Term Loan Note shall have the meanings given to them in the Amended and Restated
Credit Facility Agreement dated as of September 30, 1998 between the undersigned
("Detection"),  Radionics,  Inc. and Fleet  National Bank (as successor to Fleet
Bank, "Bank"), as the same may be amended, extended,  replaced, or modified from
time to time (the "Credit Agreement").

     This  Amended and  Restated  Term Loan Note,  in part,  evidences  the same
obligations  as evidenced by, and amends and restates in its entirety,  the Term
Loan Note dated May 31, 1996 in the  original  principal  amount of  $14,350,000
given by the  Borrower to the Bank,  as amended and  restated by the Amended and
Restated Term Loan Note dated June 24, 1997 given by the Borrower to the Bank.

     FOR VALUE  RECEIVED,  Detection  hereby promises to pay to the order of the
Bank, at any of its banking offices, or at such other places as Bank may specify
in writing to Borrower,  the  principal  sum of Fourteen  Million  Three Hundred
Fifty Thousand Dollars ($14,350,000).

     Interest.  Outstanding  principal  amounts  under this Term Loan Note shall
bear interest until paid in full at the Base Rate plus the Applicable  Base Rate
Margin.  Changes in the rate of interest applicable to this Term Loan Note shall
become effective  automatically and without notice at the time of changes in the
Base Rate.

     Detection,  however,  at least two business  days prior to each Rate Change
Date may notify the Bank of its  election  to have a portion of the  outstanding
principal  amount  under this Term Loan Note (which must be at least  $1,000,000
and  must  be  an  increment  of  $100,000)   bear  interest  for  a  one-month,
three-month,  or six month  period  commencing  on such Rate  Change Date at the
LIBOR Rate plus the Applicable LIBOR Margin.
<PAGE>

     Interest shall be calculated based on actual days elapsed divided by a year
of 360 days.

     Interest  shall  continue to accrue after  maturity at the rate required by
this  Term  Loan Note  until  this  Term Loan Note is paid in full.  The rate of
interest  on this  Term  Loan  Note may be  increased  under  the  circumstances
provided in the Credit  Agreement.  The right of Bank to receive such  increased
rate of interest  shall not  constitute a waiver of any other right or remedy of
Bank.

     Payments.  Payments of all accrued interest under this Term Loan Note shall
be due and payable on the first day of each month.  In addition,  commencing  on
March 1, 2000,  principal  payments of $217,424.24 each shall be due and payable
on the first day of each month.

     All  Obligations  under and related to this Term Loan Note shall be due and
payable in full on September 30, 2005.

     All payments  shall be in lawful money of the United States in  immediately
available funds. Unless canceled in writing by Detection,  Detection  authorizes
Bank to debit its  accounts at Bank to make  payments  due  hereunder,  but such
authority shall not relieve  Detection of the obligation to assure that payments
are made when due.

     Late Charge. This Term Loan Note is subject to the late charges provided in
the Credit Agreement.

     Maximum Rate. All agreements between Borrower and Bank are hereby expressly
limited  so that in no  contingency  or event  whatsoever,  whether by reason of
acceleration  of maturity of the  indebtedness  evidenced  hereby or  otherwise,
shall  the  amount  paid  or  agreed  to be  paid  to  Bank  for  the use or the
forbearance of the indebtedness  evidenced hereby exceed the maximum permissible
under  applicable law. As used herein,  the term "applicable law" shall mean the
law in effect as of the date hereof provided, however that in the event there is
a change in the law which results in a higher permissible rate of interest, then
this Note shall be governed by such new law as of its  effective  date.  In this
regard,  it is  expressly  agreed that it the intent of Borrower and Bank in the
execution, delivery and acceptance of this Note to contract in strict compliance
with the laws of the State of New York from time to time in effect. If, under or
from any circumstances whatsoever, fulfillment of any provision hereof or of any
other documents  between the Borrower and the Bank at the time of performance of
such  provision  shall be due,  shall  involve  transcending  the  limit of such
validity prescribed by applicable law, then the obligation to be fulfilled shall
automatically  be reduced to the limits of such  validity,  and if under or from
circumstances  whatsoever  Bank should ever receive as interest and amount which
would  exceed the highest  lawful  rate,  such amount  which would be  excessive
interest  shall be applied to the reduction of the principal  balance  evidenced
hereby and not to the payment of interest.  This  provision  shall control every
other provision of all agreements between Borrower and Bank.

     Prepayment. This Term Loan Note is freely prepayable in whole or in part at
any time,  subject to payment of Break Costs,  if any, as provided in the Credit
Agreement.

     Holidays.  If this Term Loan Note or any payment hereunder becomes due on a
Saturday,  Sunday or other holiday on which the Bank is authorized to close, the
due  date of this  Term  Loan  Note or  payment  shall be  extended  to the next
succeeding business day, but any interest or fees shall be calculated based upon
the actual time of payment.

     Events of  Default.  At Bank's  option,  this Term Loan Note  shall  become
immediately due and payable in full upon the happening of any Event of Default.
<PAGE>
     Modification of Terms.  The terms of this Term Loan Note cannot be changed,
nor may this  Term  Loan  Note be  discharged  in whole or in part,  except by a
writing  executed  by Bank.  In the event that Bank  demands or accepts  partial
payments of this Term Loan Note,  such demand or acceptance  shall not be deemed
to constitute a waiver of the right to demand the entire unpaid  balance of this
Term Loan Note at any time in  accordance  with the terms  hereof.  Any delay or
omission  by Bank in  exercising  any rights  hereunder  shall not  operate as a
waiver of such rights.

     Collection  Costs.  Detection  on demand  shall pay all  expenses  of Bank,
including  without  limitation  reasonable  attorneys'  fees, in connection with
enforcement and collection of this Term Loan Note.

     Miscellaneous.  To the fullest extent  permissible by law, Detection waives
presentment,  demand for payment, protest, notice of non-payment,  and all other
demands or notices  otherwise  required by law in connection  with the delivery,
acceptance,  performance,  default,  or  enforcement  of this  Term  Loan  Note.
Detection  consents to  extensions,  postponements,  indulgences,  amendments to
notes and agreements, substitutions or releases of collateral, and substitutions
or releases of other parties primarily or secondarily liable herefor, and agrees
that none of the same shall affect Detection's  obligations under this Term Loan
Note which shall be unconditional.

     Laws.  Detection  agrees  that this Term Loan Note shall be governed by the
laws of the State of New York.


                                 DETECTION SYSTEMS, INC.

                                 By: /s/Frank J. Ryan, Secretary & Treasurer