1991 STOCK OPTION PLAN

                                       OF

                                 METRO-TEL CORP.

                          (AS AMENDED OCTOBER 25, 1996)

          1.   PURPOSES  OF THE PLAN.  This stock  option  plan (the  "Plan") is
designed to promote the  interests of Metro-Tel  Corp.,  a Delaware  corporation
(the "Company"), and its present and future subsidiary corporations,  as defined
in Paragraph 19  ("Subsidiaries"),  in  attracting  and  retaining key employees
(including  directors  and officers who are key  employees)  by enabling them to
acquire or increase a  proprietary  interest  in the  Company,  to benefit  from
appreciation in the value of the Company's  Common Stock and, thus,  participate
in the  long-term  growth of the Com pany.  The Plan  provides  for the grant of
"incentive  stock  options"  ("ISOs")  within the  meaning of Section 422 of the
Internal Revenue Code of 1986, as amended (the "Code"),  and nonqualified  stock
options ("NQSOs"),  but the Company makes no warranty as to the qualification of
any option as an "incentive stock option" under the Code.

          2.   STOCK SUBJECT TO THE PLAN. Subject to the provisions of Paragraph
12, the aggregate  number of shares of Common Stock,  $.025 par value per share,
of the Company  ("Common Stock") for which options may be granted under the Plan
shall not exceed 250,000.  Such shares of Common Stock may, in the discretion of
the Board of Directors of the Company (the "Board of Directors"), consist either
in whole or in part of authorized but unissued  shares of Common Stock or shares
of Common Stock held in the treasury of the  Company.  The Company  shall at all
times  during the term of the Plan  reserve  and keep  available  such number of
shares of Common Stock as will be sufficient to satisfy the  requirements of the
Plan.  Subject to the  provisions  of  Paragraph  13, any shares of Common Stock
subject to an option which for any reason expires,  is canceled or is terminated
unexercised or which ceases for any reason to be exercisable  shall again become
available for the granting of options under the Plan.

          3.   ADMINISTRATION OF THE PLAN. The Plan shall be administered by the
Board of  Directors  which,  to the extent it shall  determine  may delegate its
powers with  respect to the  administration  of the Plan to a  Committee  of the
Board of Directors  of the Company  consisting  of not less than two  directors,
each of whom shall be a "non-employee director" within the meaning of Rule 16b-3
(or any successor rule or regulation)  promulgated under the Securities Exchange
Act of  1934,  as  amended  (the  "Exchange  Act").  References  in the  Plan to
determinations   or  actions  by  the  Committee  shall  be  deemed  to  include
determinations and actions by the Board of Directors.

          Subject to the express  provisions of the Plan,  the  Committee  shall
have the authority,  in its sole discretion,  to determine the key employees who
shall receive  options;  the times when they shall receive  options;  whether an
option  shall be an ISO or a NQSO;  the  number of shares of Common  Stock to be
subject to each  option;  the term of each  option;  the date each option  shall
become exercisable;  whether an option shall be exercisable in whole, in part or
in installments, and,


<PAGE>



if in  installments,  the number of shares of Common Stock to be subject to each
installment,  the date each installment shall become exercisable and whether the
installments shall be cumulative;  whether to accelerate the date of exercise of
any  option or  installment;  whether  shares  of Common  Stock may be issued on
exercise  of an  option as partly  paid,  and,  if so,  the  dates  when  future
installments  of the  exercise  price  shall  become due and the amounts of such
installments;  the  exercise  price of each  option;  the form of payment of the
exercise  price;  the  amount,  if  any,  necessary  to  satisfy  the  Company's
obligation to withhold taxes;  whether to restrict the sale or other disposition
of the shares of Common  Stock  acquired  upon the  exercise of an option and to
waive any such  restriction;  whether  to  subject  the  exercise  of all or any
portion of an option to the  fulfillment  of  contingencies  as specified in the
Contract  referred  to in  Paragraph  11  (the  "Contract"),  including  without
limitation,  contingencies  relating to entering  into a covenant not to compete
with the Company and its Parent and  Subsidiaries,  to financial  objectives for
the Company, a Subsidiary, a division, a product line or other category,  and/or
the period of continued  employment of the optionee with the Company, its Parent
or its Subsidiaries,  and to determine whether such contingencies have been met;
to  construe  the  respective  Contracts  and the Plan;  with the consent of the
optionee, to cancel or modify an option,  provided such option as modified would
be  permitted  to be  granted  on such date  under  the  terms of the  Plan;  to
prescribe,  amend and rescind rules and regulations relating to the Plan; and to
make all other determinations necessary or advisable for administering the Plan.
The determinations of the Committee on the matters referred to in this Paragraph
3 shall be conclusive.

          4.   ELIGIBILITY.  The Committee may,  consistent with the purposes of
the Plan, grant options from time to time, to key employees (including directors
and officers who are key  employees) of the Company or any of its  Subsidiaries.
Options  granted  shall  cover  such  number of  shares  of Common  Stock as the
Committee may  determine;  provided,  however,  that the aggregate  market value
(determined at the time the option is granted) of the shares of Common Stock for
which any  eligible  person may be granted ISOs under the Plan or any other plan
of the  Company,  or of a Parent  or a  Subsidiary  of the  Company,  which  are
exercisable  for the first time by such optionee  during any calendar year shall
not exceed $100,000. The $100,000 ISO limitation shall be applied by taking ISOs
into account in the order in which they were granted. Any option (or the portion
thereof) granted in excess of such amount shall be treated as a NQSO.

          5.   EXERCISE PRICE.  The exercise price of the shares of Common Stock
under each option shall be determined by the Committee;  provided, however, that
the  exercise  price shall not be less than 100% of the fair market value of the
Common Stock subject to such option on the date of grant; and further  provided,
that if, at the time an ISO is granted,  the optionee  owns (or is deemed to own
under Section  424(d) of the Code) stock  possessing  more than 10% of the total
combined  voting  power of all  classes of stock of the  Company,  of any of its
Subsidiaries  or of a Parent,  the exercise  price of such ISO shall not be less
than 110% of the fair market  value of the Common  Stock  subject to such ISO on
the date of grant.

          The fair market  value of the Common  Stock on any day shall be (a) if
the principal market for the Common Stock is a national securities exchange, the
average between the high and low sales prices of the Common Stock on such day as
reported by such exchange or on a consolidated  tape reflecting  transactions on
such exchange, (b) if the principal market for the

                                       -2-

<PAGE>



Common  Stock is not a national  securities  exchange  and the  Common  Stock is
quoted on the National  Association of Securities  Dealers Automated  Quotations
System  ("NASDAQ"),  and (i) if actual sales price information is available with
respect to the Common Stock,  the average  between the high and low sales prices
of the Common Stock on such day on NASDAQ,  or (ii) if such  information  is not
available,  the average  between the highest bid and the lowest asked prices for
the Common Stock on such day on NASDAQ,  or (c) if the principal  market for the
Common Stock is not a national  securities  exchange and the Common Stock is not
quoted on NASDAQ,  the average  between the highest bid and lowest  asked prices
for the Common  Stock on such day as reported on the NASDAQ OTC  Bulletin  Board
Service or by National Quotation Bureau,  Incorporated or a comparable  service;
provided  that  if  clauses  (a),  (b)  and  (c)  of  this   Paragraph  are  all
inapplicable, or if no trades have been made or no quotes are available for such
day,  the fair  market  value of the Common  Stock  shall be  determined  by the
Committee by any method  consistent with applicable  regulations  adopted by the
Treasury  Department  relating  to  stock  options.  The  determination  of  the
Committee shall be conclusive in determining the fair market value of the stock.

          6.   TERM OF OPTIONS.  The term of each option granted pursuant to the
Plan  shall  be such  term  as is  established  by the  Committee,  in its  sole
discretion,  at or before the time such  option is granted;  provided,  however,
that the term of each ISO granted pursuant to the Plan shall be for a period not
exceeding ten (10) years from the date of grant thereof, and further,  provided,
that if, at the time an ISO is granted,  the optionee  owns (or is deemed to own
under Section 424(d) of the Code) stock  possessing  more than ten (10%) percent
of the total  combined  voting power of all classes of stock of the Company,  of
any of its  Subsidiaries  or of a  Parent,  the  term of the ISO  shall be for a
period not  exceeding  five (5) years from the date of grant.  Options  shall be
subject to earlier termination as hereinafter provided.

          7.   EXERCISE.  An option (or any part or installment thereof), to the
extent then  exercisable,  shall be  exercised by giving  written  notice to the
Company  (attention:  President) at its principal  office,  stating which ISO or
NQSO is being  exercised,  specifying the number of shares of Common Stock as to
which such option is being  exercised and  accompanied by payment in full of the
aggregate exercise price therefor (or the amount due on exercise if the Contract
permits installment  payments) (a) in cash or by certified check or (b) with the
consent  of the  Committee  (in the  Contract  or  otherwise),  with  previously
acquired  shares of Common Stock having an aggregate  fair market value,  on the
date of exercise,  equal to the  aggregate  exercise  price of all options being
exercised,  or with any combination of cash, certified check or shares of Common
Stock.  The Committee  may, in its  discretion,  permit  payment of the exercise
price of options by delivery of a properly  executed  exercise notice,  together
with  a  copy  of  irrevocable  instructions  from  the  Optionee  to  a  broker
(acceptable to the  Committee) to deliver  promptly to the Company the amount of
sale or loan proceeds to pay such exercise  price.  To facilitate the foregoing,
the Company may enter into  agreements for  coordinated  procedures  with one or
more brokerage firms.

          A person  entitled  to receive  Common  Stock upon the  exercise of an
option shall not have the rights of a stockholder with respect to such shares of
Common Stock until the date of

                                       -3-

<PAGE>



issuance of a stock certificate to him for such shares; provided,  however, that
until such stock  certificate  is issued,  any option  holder  using  previously
acquired  shares of Common  Stock in payment of an option  exercise  price shall
continue to have the rights of a  stockholder  with  respect to such  previously
acquired shares.

          No option may be  exercised  in an amount less than 100 shares (or the
remaining shares then covered by the option if less than 100 shares). In no case
may a fraction of a share of Common Stock be purchased or issued under the Plan.

          8.   TERMINATION  OF  EMPLOYMENT.   Any  holder  of  an  option  whose
employment with the Company (and its Parent and Subsidiaries) has terminated for
any reason other than his death or  Disability  (as defined in Paragraph 19) may
exercise such option, to the extent exercisable on the date of such termination,
at any  time  within  three  months  after  the  date  of  termination,  but not
thereafter  and in no event  after  the date the  option  would  otherwise  have
expired;  provided,  however,  that if his employment shall be terminated either
(a) for cause,  or (b)  without the consent of the  Company,  said option  shall
terminate immediately upon termination of employment.  Options granted under the
Plan shall not be  affected by any change in the status of the holder so long as
he continues to be a full-time employee of the Company, its Parent or any of the
Subsidiaries  (regardless  of having been  transferred  from one  corporation to
another).

          For the  purposes of the Plan,  an  employment  relationship  shall be
deemed to exist between an individual  and a corporation  if, at the time of the
determination,  the individual was an employee of such  corporation for purposes
of Section  422(a) of the Code. As a result,  an  individual  on military,  sick
leave or other bona fide leave of absence  shall  continue to be  considered  an
employee  for  purposes of the Plan during such leave if the period of the leave
does not exceed 90 days,  or, if longer,  so long as the  individual's  right to
reemployment with the Company (or a related corporation) is guaranteed either by
statute  or by  contract.  If the  period  of  leave  exceeds  90  days  and the
individual's  right to reemployment is not guaranteed by statute or by contract,
the employment  relationship  shall be deemed to have terminated on the 91st day
of such leave.

          Nothing  in the Plan or in any  option  granted  under the Plan  shall
confer on any individual any right to continue in the employ of the Company, its
Parent or any of its Subsidiaries, or interfere in any way with the right of the
Company,  its Parent or any of its  Subsidiaries  to  terminate  the  employee's
employment  at any time  for any  reason  whatsoever  without  liability  to the
Company, its Parent or any of its Subsidiaries.

          9.   DISABILITY OR DEATH OF AN OPTIONEE. Any optionee whose employment
has  terminated by reason of Disability  may exercise his option,  to the extent
exercisable upon the effective date of such termination,  at any time within one
year after  such date,  but not  thereafter  and in no event  after the date the
option would otherwise have expired.

          If an  optionee  dies (a) while he is  employed  by the  Company,  its
Parent or any of its Subsidiaries, (b) within three months after the termination
of his employment (unless such termination

                                       -4-

<PAGE>



was for cause or without the consent of the Company or by reason of  Disability)
or (c) within one year following the  termination of his employment by reason of
Disability,  the option may be exercised,  to the extent exercisable on the date
of his  death,  by his  executor,  administrator  or  other  person  at the time
entitled  by law to his rights  under such  option,  at any time within one year
after death,  but not thereafter and in no event after the date the option would
otherwise have expired.

          10.  COMPLIANCE WITH SECURITIES LAWS. The Committee may require in its
discretion,  as a condition  to the  exercise  of any option,  that either (a) a
Registration  Statement  under  the  Securities  Act of 1933,  as  amended  (the
"Securities  Act"), with respect to the shares of Common Stock to be issued upon
such exercise shall be effective and current at the time of exercise,  or (b) in
the opinion of counsel for the Company,  there is an exemption from registration
under the Securities  Act for the issuance of such shares.  Nothing herein shall
be construed as requiring the Company to register  shares  subject to any option
under the Securities  Act. The Committee may require the optionee to execute and
deliver to the Company his  representation  and warranty,  in form and substance
satisfactory to the Committee, that the shares of Common Stock to be issued upon
the  exercise  of the  option are being  acquired  by the  optionee  for his own
account,  for investment  only and not with a view to the resale or distribution
thereof.  In addition,  the  Committee may require the optionee to represent and
warrant in  writing  that any  subsequent  resale or  distribution  of shares of
Common Stock by such optionee  will be made only pursuant to (i) a  Registration
Statement  under the  Securities Act which is effective and current with respect
to the shares of Common Stock being sold, or (ii) a specific  exemption from the
registration requirements of the Securities Act, but in claiming such exemption,
the  optionee  shall prior to any offer of sale or sale of such shares of Common
Stock provide the Company with a favorable  written opinion of counsel,  in form
and sub stance  satisfactory  to the Company,  as to the  applicability  of such
exemption to the proposed sale or distribution.

          In  addition,  if at any time the  Committee  shall  determine  in its
discretion  that the  listing or  qualification  of the  shares of Common  Stock
subject to such option on any securities  exchange or under any applicable  law,
or the consent or approval of any governmental  regulatory body, is necessary or
desirable as a condition to, or in connection with, the granting of an option or
the issue of shares of Common Stock thereunder, such option may not be exercised
in whole or in part  unless  such  listing,  qualification,  consent or approval
shall have been effected or obtained free of any  conditions  not  acceptable to
the Committee.

          11.  STOCK  OPTION  CONTRACTS.  Each option  shall be  evidenced by an
appropriate  Contract  which  shall  be duly  executed  by the  Company  and the
optionee,  and shall contain such terms and conditions not inconsistent herewith
as may be determined by the Committee.

          12.  ADJUSTMENTS  UPON CHANGES IN COMMON STOCK.  Notwith  standing any
other  provisions  of the Plan,  in the event of any  change in the  outstanding
Common  Stock by reason of a stock  dividend,  stock split,  stock  combination,
recapitalization,  merger or consolidation in which the Company is the surviving
corporation, reorganization or the like, the aggregate number and kind of shares
subject to the Plan, the aggregate number and kind of shares

                                       -5-

<PAGE>



subject to each  outstanding  option and the  exercise  price  thereof  shall be
appropriately  adjusted by the Board of Directors,  whose determination shall be
conclusive.

          In the event of (a) the liquidation or dissolution of the Company, (b)
a merger or consolidation in which the Company is not the surviving corporation,
or (c) any other capital  reorganization in which more than 50% of the shares of
Common Stock of the Company  entitled to vote in the  election of directors  are
exchanged,  outstanding options shall terminate,  unless other provision is made
therefor in the transaction.

          13.  AMENDMENTS  AND  TERMINATION OF THE PLAN. The Plan was adopted by
the Board of Directors on September 26, 1991. No option may be granted under the
Plan after September 25, 2001. The Board of Directors,  without further approval
of the Company's stockholders, may at any time suspend or terminate the Plan, in
whole or in part,  or amend it from time to time in such respects as it may deem
advisable,  including,  without limitation, in order that ISOs granted hereunder
meet the  requirements  for "incentive  stock options" under the Code, to comply
with applicable  requirements of the Securities Act and the Exchange Act, and to
conform  to any  change  in  applicable  law or to  regulations  or  rulings  of
administrative agencies; provided, however, that no amendment shall be effective
without the requisite prior or subsequent  stockholder  approval which would (a)
change  the  class  of  those  eligible  to  receive  options,   (b)  except  as
contemplated  in Paragraph 12,  increase the maximum  number of shares of Common
Stock for which  options may be granted  under the Plan,  (c) extend the term of
the 1991 Plan or (d) materially  increase the benefits to participants under the
Plan. No  termination,  suspension  or amendment of the Plan shall,  without the
consent of the holder of an existing option affected  thereby,  adversely affect
his  rights  under such  option.  The power of the  Committee  to  construe  and
administer  any  options  granted  under the Plan  prior to the  termination  or
suspension of the Plan  nevertheless  shall continue  after such  termination or
during such suspension.

          14.  NON-TRANSFERABILITY  OF OPTIONS. No option granted under the Plan
shall  be  transferable  otherwise  than  by will or the  laws  of  descent  and
distribution,  and options may be  exercised,  during the lifetime of the holder
thereof, only by him or his legal representatives. Except to the extent provided
above,  options  may not be  assigned,  transferred,  pledged,  hypothecated  or
disposed of in any way (whether by operation of law or otherwise)  and shall not
be subject to execution, attachment or similar process.

          15.  WITHHOLDING  TAXES.  The Company may (i) require the holder of an
option to pay, or the Company may withhold,  cash,  and/or (ii) with the consent
of the  Committee (in the Contract or  otherwise),  accept  previously  acquired
shares of Common Stock  and/or may withhold  shares of Common Stock to be issued
with respect to the option having an aggregate  fair market value  determined on
the date of exercise of the option or date of  disposition  of the shares issued
upon exercise of the option  determined in accordance  with Paragraph 5, in each
case  equal to the amount  which it  determines  is  necessary  to  satisfy  its
obligation  to withhold  Federal,  state and local  income  taxes or other taxes
incurred by reason of the grant or exercise of an option or the  disposition  of
the underlying shares of Common Stock, as the case may be. The Company shall not
be required to issue

                                       -6-

<PAGE>



any  shares of Common  Stock  pursuant  to any such  option  until all  required
payments have been made.

          16.  LEGENDS; PAYMENT OF EXPENSES. The Company may endorse such legend
or legends upon the certificates for shares of Common Stock issued upon exercise
of an option under the Plan and may issue such "stop  transfer"  instructions to
its  transfer  agent  in  respect  of  such  shares  as it  determines,  in  its
discretion,  to be necessary or appropriate to (a) prevent a violation of, or to
perfect an exemption from, the registration  requirements of the Securities Act,
(b)  implement the  provisions of the Plan or any agreement  between the Company
and the optionee with respect to such shares of Common Stock,  or (c) permit the
Company  to  determine  the  occurrence  of a  "disqualifying  disposition,"  as
described  in  Section  421(b)  of the  Code,  of the  shares  of  Common  Stock
transferred upon the exercise of an ISO granted under the Plan.

          The Company shall pay all issuance  taxes with respect to the issuance
of shares of Common Stock upon the exercise of an option granted under the Plan,
as well as all fees and expenses incurred by the Company in connection with such
issuance.

          17.  USE OF  PROCEEDS.  The cash  proceeds  from the sale of shares of
Common Stock  pursuant to the exercise of options  under the Plan shall be added
to the general funds of the Company and used for such corporate  purposes as the
Board of Directors may determine.

          18.  SUBSTITUTIONS  AND ASSUMPTIONS OF OPTIONS OF CERTAIN  CONSTITUENT
CORPORATIONS.  Anything in this Plan to the contrary notwithstanding,  the Board
of Directors may, without further approval by the  stockholders,  substitute new
options for prior options of a Constituent  Corporation (as defined in Paragraph
19) or assume the prior options of such Constituent Corporation.

          19.  DEFINITIONS.

               (a)  Subsidiary.  The  term  "Subsidiary"  shall  have  the  same
definition as "subsidiary corporation" in Section 424(f) of the Code.

               (b)  Parent.  The term "Parent" shall have the same definition as
"parent corporation" in Section 424(e) of the Code.

               (c)  Constituent Corporation.  The term "Constituent Corporation"
shall mean any  corporation  which  engages with the Company,  its Parent or any
Subsidiary  in a  transaction  to which  Section  424(a) of the Code applies (or
would apply if the option assumed or substituted  were an ISO), or any Parent or
any Subsidiary of such corporation.

               (d)  Disability. The term "Disability" shall mean a permanent and
total disability within the meaning of Section 22(e)(3) of the Code.


                                       -7-

<PAGE>


          20.  GOVERNING LAW. The Plan, such options as may be granted hereunder
and all related matters shall be governed by, and construed in accordance  with,
the laws of the State of Delaware.

          21.  PARTIAL INVALIDITY. The invalidity or illegality of any provision
herein shall not affect the validity of any other provision.

          22.  STOCKHOLDER APPROVAL.  The Plan shall be subject to approval by a
majority of the votes  present in person or by proxy at the next  meeting of the
Company's  stockholders  at  which a  quorum  is  present.  No  options  granted
hereunder  may be exercised  prior to such  approval,  provided that the date of
grant of any options  granted  hereunder  shall be determined as if the Plan had
not been subject to such approval. Notwithstanding the foregoing, if the Plan is
not approved by a vote of the stockholders of the Company on or before September
25, 1992, the Plan and any options granted hereunder shall terminate.


                                       -8-