<PAGE>
 
                                                                   Exhibit 10.48

                                MASTER AGREEMENT
                                      for
                             PROFESSIONAL SERVICES
--------------------------------------------------------------------------------


     This Master Agreement ("Agreement") dated ___June 16_____________, 1997 is
entered into between:


               "Cambridge"                     And  "Client"


          Cambridge Technology Partners             Lifeline Systems, Inc.
          -----------------------------             ----------------------
          304 Vassar Street                         640 Memorial Drive
          -----------------                         ------------------
          Cambridge, MA  02139                      Cambridge, MA 02139
          --------------------                      -------------------

This Agreement describes the terms and conditions under which Cambridge will
provide professional services for Client and supersedes all prior written and
oral understandings between Cambridge and Client.  Services will be authorized
via Work Orders issued pursuant to this Agreement.

1.  WORK ORDERS
---------------

Individual service engagements performed under this Agreement will be defined by
a Work Order in the form of Exhibit A.  Work Orders will include a description
of the services to be provided, pricing, payment schedule, special terms and
conditions applicable to the specific Work Order and a Statement of Work (a
Statement of Work outline is provided as Exhibit B; hereafter, each Work Order
and related Statement of Work are referred to collectively as a "Work Order").
Each Work Order, together with the terms of this Agreement, is a separate
contract that will be effective as of the date signed by authorized
representatives of both Cambridge and Client.  If any terms of the Work Order
(including the Statement of Work) conflict with the terms of this Agreement, the
terms of the Work Order will take precedence.  If any term or provision of this
Agreement, or any Work Order, is held invalid or unenforceable for any reason,
the remainder of the provisions of this Agreement and/or Work Order will
continue in full force and effect.

2.  EXPENSES
------------

In addition to the price identified within each Work Order, Client is
responsible for the following documented expenses incurred by Cambridge while
performing services under this Agreement which have been pre-approved by Client
and which are in accordance with Client's internal expense reimbursement
guidelines:  (a) reasonable travel and living expenses of Cambridge personnel,
including but not limited to airfare, mileage, parking, tolls, lodging, auto
rental and per diem, (b) computer communication expenses, (c) shipping expenses
and (d) cost of third party hardware and software.  Notwithstanding the
foregoing, except as otherwise set forth in the 

                                       1
<PAGE>
 
applicable Work Order, Client shall not be liable for any expenses of Cambridge
in connection with a project in excess of 18% of the fixed project cost stated
on the applicable Work Order. Payment for expenses is due 30 days following
receipt of Cambridge's invoice.

3.  INVOICES
------------

Unless otherwise indicated in a Work Order, invoices for services and expenses
shall be rendered semi-monthly, or upon completion of the services if the
duration of the Work Order is less than one month.  Invoices shall be payable
upon receipt and sent to:

               Organization:      Lifeline Systems, Inc.
               Street Address:    640 Memorial Drive
               City, State, Zip:  Cambridge, MA  02139
               Attention:         Richard M. Reich

4.  CHANGES
-----------

(a)  Neither this Agreement, nor any Work Order, may be modified or amended
     except via written change order signed by an authorized representative of
     both parties (a "Change Order").  If Client requests or Cambridge
     recommends changes during performance of a Work Order, Cambridge will
     provide Client with a written change order proposal setting forth (a) a
     description of the proposed change(s), (b) impact on price, (c) impact on
     production schedule and (d) a proposed revision of the Statement of Work.
     Client may, at its discretion, accept or reject the change order proposal.
     A change order proposal will be considered rejected if Client does not
     respond to the proposal within ten business days.  If accepted, Change
     Orders will be effective upon execution by both parties.

(b)  Notwithstanding the above, Cambridge may, after consultation with Client,
     make minor modifications to software design specifications if such
     modifications do not limit, diminish or affect the functional operation or
     use of the software or its output, increase Client expense or delay the
     production schedule.

5.  DELAYS
----------

If Cambridge notifies Client in writing that any phase of a Work Order will be
extended because Client materially failed to meet its responsibilities
identified within the Work Order, such delay will constitute a change and,
unless Client instructs Cambridge not to perform such work, Client will pay
Cambridge's standard time and material rates for the extended work (which costs
and fees shall in the aggregate be reasonable).  In no other case will Client be
responsible for increased costs or fees resulting from the delay or extension of
any project or service provided by Cambridge.

                                       2
<PAGE>
 
6.  CONTINUATION OF SERVICES
----------------------------

In order to maintain the rapid timeframes of a project, it is important to
ensure the continuity from one project phase to the next.  To prevent impact to
a project, it may be necessary for Cambridge to continue into the next phase
even if all project related issues have not been fully resolved.  An Interim
Agreement in the form of Exhibit C allows Cambridge to maintain the project team
and begin work on the next phase of a project prior to the execution of a formal
Work Order.  Under an Interim Agreement duly executed by both parties, Client
pays Cambridge for the services in two week increments plus travel and living
expenses.  The Work Order, once in place, will supersede the Interim Agreement
and payments made under the Interim Agreement will be applied to the price
specified in the Work Order.

7.  CONFIDENTIALITY
-------------------

Each party acknowledges that information provided by either party in connection
with this Agreement may contain confidential and proprietary data, and
disclosure of such information may be damaging to the disclosing party.  During
the performance of services under this Agreement it may be necessary for either
party to provide the other with certain information considered to be proprietary
or confidential by the disclosing party.  Cambridge and Client, their
successors, assignees, officers, directors, employees and agents, agree that
such information will be provided subject to the following terms and conditions:


(a)  The term "Information", as used in this section, denotes any and all
     technical and business information disclosed in any manner or form
     including, but not limited to financial plans and records, marketing plans,
     business strategies, trade secrets, present and proposed products, computer
     software programs, source code, relationships with third parties, customers
     lists, information regarding customers and suppliers, founders, employees,
     and affiliates.

(b)  Information of the disclosing party will be protected from disclosure to
     anyone other than the directors, officers, employees, consultants and
     contractors of the receiving party who have a need to have access to such
     Information to perform obligations or exercise rights under this Agreement
     and who are obligated to maintain the confidentiality of such Information.
     Each party will use the same degree of care to protect Information of the
     other party as it uses to protect its own Information of like importance,
     but no less than a reasonable degree of care.

(c)  The disclosing party's Information will be used only as necessary for
     performance of the receiving party's obligations under the applicable Work
     Order.  Neither party will make more copies of the Information than are
     necessary.

(d)  The receiving party will not have any obligation with respect to any
     Information of the 

                                       3
<PAGE>
 
     disclosing party which the receiving party can establish:

     (i)   is or becomes publicly available through no wrongful act of the
           receiving party;

     (ii)  was lawfully obtained by the receiving party from a third party
           without any obligation to maintain the Information as proprietary or
           confidential;

     (iii) was previously known to the receiving party without any obligation
           to keep it confidential; or

     (iv)  was independently developed by the receiving party without reference
           to or reliance on the Information.

     Notwithstanding the exceptions contained in Sections 7(d)(iii) and (iv)
     above, the Custom Software and all related source code, designs,
     documentation and materials shall constitute the confidential Information
     of Client.

(e)  No license to either parties' Information is either granted or implied by
     the disclosure of Information.

(f)  Within 14 days of a request by the disclosing party the receiving party
     shall return all property including but not limited to documents, records,
     tapes, and any other media as well as all copies thereof in its possession
     or under its control that contains Information of the disclosing party,
     except, with respect to Information of Cambridge, to the extent such
     Information is incorporated in a Deliverable.

(g)  The duties and obligations to protect Information will survive termination
     of this Agreement.

(h)  The parties recognize and acknowledge that the Information may have
     competitive value and that irreparable damage might result to the
     disclosing party if Information is improperly disclosed by the receiving
     party to any non-authorized third party.  The parties agree that legal
     proceedings at law or in equity, including injunctive relief, may be
     appropriate in the event of a breach hereof.

8.  OWNERSHIP (GENERAL)
-----------------------

(a)  Material first produced or created by Cambridge for Client under any Work
     Order shall belong exclusively to Client, and Cambridge shall have no right
     to utilize such material for its own use.  Cambridge shall retain ownership
     of any pre-existing Cambridge materials (such as Training Materials)
     identified in writing as such under any Work Order.  Cambridge grants to
     Client a perpetual, worldwide, non-exclusive, non-transferable license, at
     no additional charge, to use such pre-existing materials for Client's

                                       4
<PAGE>
 
     internal business purposes only (it being understood that the foregoing
     shall not apply to Cambridge Components-In, which are subject to Exhibit D
     below).  Access to such pre-existing materials will be restricted to
     Client's employees, contractors, agents and consultants who are obligated
     to maintain the confidentiality of such materials.

(b)  Cambridge shall retain all rights in its proprietary methodologies for
     delivery of its Scoping, Rapid Solutions Workshop, Software Design and
     Development and Package Implementation services ("Methodology") which may
     be used by Cambridge and/or provided by Cambridge to Client during the
     course of a Work Order.  Client agrees to hold Cambridge's methodologies in
     confidence in accordance with the Confidentiality clause of this Agreement.

9.  OWNERSHIP (SOFTWARE)
------------------------

The categories of software associated with an application development project,
including software ownership and license rights, are defined below.


(a)  Custom Software:  Software developed or created by Cambridge for Client
     under a Work Order, excluding Third Party Software, Cambridge Components-In
     and Cambridge Components-Out.  Custom Software is owned by the Client.
     Cambridge hereby assigns all rights, title and interest in Custom Software
     to Client, as it is developed.

(b)  Third Party Software:  Pre-existing software components owned by a third
     party and used in developing the Client software application.  Third Party
     Software is generally licensed directly from the Third Party to Client.
     Cambridge will not use Third Party Software in connection with the
     performance of services hereunder without the written consent of Client.

(c)  Software Re-Use:  Employing a pre-existing software component as a building
     block when developing a software application.  A detailed explanation of
     Cambridge's Software Re-Use Program is provided in Exhibit D.  For purposes
     of this Agreement, no components will be classified as Cambridge
     Components-In or Cambridge Components-Out.  In the event the parties agree
     to amend this Agreement to provide for "Components-In" or "Components-Out",
     this Agreement will also be amended to provide for mutually agreeable
     license terms relating thereto.

     (i)  Cambridge Components-In:  Pre-existing Cambridge software components
          (or software developed by Cambridge staff not directly involved in
          Client's project) used by Cambridge as a development building block in
          the Client software application.

     (ii) Cambridge Components-Out:  Re-usable Cambridge software components
          created 

                                       5
<PAGE>
 
          during development of the Client software application. A software
          component will be deemed to be a "Component-Out" only when Cambridge
          and Client have agreed to classify it as such and have acknowledged
          this classification in a signed Work Order.

10.  ACCEPTANCE OF DELIVERABLES
-------------------------------

(a)  Cambridge shall deliver software, documentation and other materials called
     for in the Statement of Work (the "Deliverables") to Client in accordance
     with the schedules set forth in the applicable Work Order.  Software will
     be delivered in executable object code form and fully commented source code
     form.

(b)  Deliverables will be deemed to have been accepted upon successful
     completion of the Acceptance Testing performed at the end of the
     Development Phase defined in the applicable Work Order.  The Acceptance
     Testing procedure will be established jointly by Cambridge and Client
     during the Development Phase.  The "success" of Acceptance Testing shall be
     evidenced by the Client's execution and delivery of the User Acceptance
     Test document related thereto.  The purpose of this Acceptance Testing is
     to determine if the Deliverables conform to their documentation and the
     Specifications developed during the Design Phase.   If Deliverables do not
     so conform, Cambridge will use its best efforts (including devoting all
     necessary resources) to cause such software to so conform as soon as
     possible.  If Cambridge is unable to cause such software to so conform
     within thirty (30) days after receipt of notice by Cambridge of such non
     conformance (or such additional cure period as Client may authorize instead
     of thirty days), Client shall have the right to terminate the Work Order.
     In such event, Cambridge will turn over to Client the Deliverables and all
     other works in progress "as is" and Cambridge and Client will negotiate in
     good faith to determine the value of the services and/or deliverables
     provided to Client.

11.  WARRANTIES
---------------

(a)  Cambridge will, at no additional charge to Client, correct Errors reported
     by Client during the Warranty Period unless otherwise specified in the
     applicable Work Order.  An Error is defined as an error in a Deliverable
     that prevents the Deliverable from performing in conformance with the
     specifications.  This warranty covers only corrections to problems with a
     Deliverable as designed and developed by Cambridge, in accordance with the
     Specifications, and does not cover Cambridge's efforts to perform
     enhancements or activities other than the correction of Errors.
     Additionally, this warranty does not cover problems caused by third party
     software or hardware products, or problems that result from software
     changes made by Client without the approval of Cambridge.  If, as a result
     of service calls placed under this warranty, Cambridge devotes staff time
     investigating problems that turn out to be problems other than Errors,
     Client will reimburse Cambridge, 

                                       6
<PAGE>
 
     on a time and materials basis, for such staff time. Cambridge will make
     every reasonable effort to minimize and/or mitigate any such additional
     charges to Client.

(b)  Cambridge further warrants that it will test, as part of its acceptance
     testing procedure, using commercially available software, all Deliverables
     for computer viruses, trojan horse, worm, time-out or other harmful or
     malicious code.  Cambridge also warrants, subject to the warranty
     restrictions contained in Section 11(a) above, that at the time of
     delivery, such Deliverables shall not experience any problems associated
     with the change of year from calendar year 1999 to 2000.

12.  INDEMNIFICATION
--------------------

(a)  Cambridge shall indemnify, defend and hold Client harmless from and against
     any losses, damages, settlements, costs and expenses (including reasonable
     attorneys' fees) arising from any claim that a Deliverable infringes or
     violates any patent, copyright, trademark, trade secret or other
     intellectual or industrial property right of any third party.

(b)  Client shall notify Cambridge promptly in writing of any third party action
     (and provide information regarding all prior related claims) brought
     against Client based on a claim described in Section 12(a) above.
     Cambridge shall defend such action at its expense and pay all expenses and
     costs attributable to such claim incurred by Client (as they are incurred),
     and all settlements and damages awarded against Client in such action or
     settlement.  Cambridge shall have sole control of the defense of any such
     action and all negotiations for its settlement or compromise. Client shall
     reasonably cooperate with Cambridge in the defense of such claim, and may
     be represented, at Client's expense, by counsel of Client's selection.

(c)  In the event that an injunction or restraint is obtained against Client's
     use of the Deliverables by reason of infringement or violation of any
     patent, copyright, trade secret, trademark or other intellectual or
     industrial property right, then Cambridge shall, using best efforts and as
     soon as possible following the entry of such injunction or restraint, at no
     charge to Client, either (i) procure for Client the right to continue to
     use the Deliverables for their intended purposes or (ii) replace or modify
     the Deliverables so that it or they become non-infringing (so long as their
     functionality is essentially unchanged).

(d)  The provisions of Section 12(a)(1) notwithstanding, Cambridge shall not
     have any liability to Client to the extent that any claim of infringement
     is based upon (a) use of the Deliverables in conjunction with any data,
     equipment or software not provided, recommended or authorized by Cambridge,
     where the Deliverable would not itself be infringing or otherwise the
     subject of the claim or (b) any modification to the Deliverables not made
     or approved by Cambridge.

                                       7
<PAGE>
 
13.  TERM AND TERMINATION
-------------------------

(a)  This Agreement shall remain in effect until terminated in writing by either
     party; provided that no such termination shall relieve either party of
     their respective obligations under any Work Order in effect at the date of
     termination of this Agreement.

(b)  Notwithstanding the foregoing, and without limiting such party's rights at
     law or in equity, either party may terminate this Agreement, and all
     existing Work Orders, if the other party has materially breached this
     Agreement or any Work Order and, except as set forth in the next sentence,
     such breach has not been cured within thirty (30) days following notice
     thereof by the other party.

(c)  Notwithstanding the foregoing, Client may, at any time, terminate work
     under a Work Order by providing Cambridge with a 30-day written termination
     notice.  The 30-day notice period will start upon Cambridge's receipt of
     the notice.  In the event of such termination, Cambridge will cease work
     immediately upon receipt of the written notice, and turn over to Client the
     Deliverables and all work in progress and Cambridge and Client will
     negotiate in good faith to determine the value of the services and/or
     deliverables provided to Client and reasonable compensation to Cambridge
     for such 30-day notice period.

(d)  Upon termination of this Agreement, all rights and obligations of the
     parties shall immediately terminate, except as follows:

     (1)  Upon termination of this Agreement, Cambridge shall provide to Client
          all Custom Software and related source code, designs, documentation
          and materials, in whatever form they exist;

     (2)  The provisions of Sections 7, 8, 9, 11, 12, 13, 14, 15, 18 and Exhibit
          D shall survive any termination of this Agreement in accordance with
          their terms.

14.  LIMITATION OF LIABILITY
----------------------------

(a)  NEITHER PARTY SHALL BE LIABLE FOR ANY INDIRECT, PUNITIVE, EXEMPLARY,
     SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT
     OR ANY WORK ORDER, WITH THE EXCEPTION OF THIRD PARTY CLAIMS ARISING UNDER
     SECTION 12 ABOVE.

(b)  EXCEPT AS STATED IN THIS AGREEMENT, CAMBRIDGE MAKES NO OTHER WARRANTIES
     EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY WARRANTIES AS TO
     MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

                                       8
<PAGE>
 
15.  SOLICITATION OF EMPLOYEES
------------------------------

Unless otherwise approved in writing by the other party, for the term of this
Agreement and twelve months beyond, neither party will offer employment to any
employee of the other party or contract with, either individually or through a
third party, any current or former employee of the other party who was involved
with the services provided under this Agreement.

16.  INDEPENDENT CONTRACTOR
---------------------------

Cambridge is an independent contractor with respect to this Agreement and Client
shall have no responsibility to provide fringe benefits or to withhold taxes
normally withheld from an employee's pay on behalf of Cambridge's employees.

17.  TAXES
----------

Prices and charges under this Agreement are exclusive of all taxes, including
state and local use, sales, property and similar taxes.  Client agrees to pay
such taxes unless Client has provided Cambridge with a valid exemption
certificate or is otherwise exempt.

18.  GOVERNING LAW
------------------

This Agreement will be governed by the laws of the Commonwealth of
Massachusetts.

19.  ASSIGNMENT
---------------

Client has selected Cambridge for the performance of the services described
herein based on the understanding that Cambridge alone shall perform such
services.  Therefore, Cambridge may not assign or subcontract its rights or
obligations under this Agreement without Client's written consent.  Client may
assign its rights and obligations under this Agreement without the consent of
Cambridge.

20.  RESTRICTIONS ON PUBLICITY
------------------------------

Neither party shall use the name(s), trademark(s), or tradename(s), whether
registered or not, of the other party in publicity releases, press releases or
advertising or in any other public written manner without prior written approval
of the other party, except as may otherwise be required by law.

In witness whereof, the parties have executed this Agreement as of the date
first written above.


CAMBRIDGE TECHNOLOGY PARTNERS      CLIENT: LIFELINE SYSTEMS, INC.

                                       9
<PAGE>
 
By:/s/ Kevin H. Schwartz        By: /s/ Richard M. Reich
   ---------------------            --------------------

Name:  Kevin H. Schwartz        Name:  Richard M. Reich
       -----------------               ----------------

Title:  Director-Contracts        Title:  Vice President
        ------------------                --------------

Exhibit A - Sample Work Order
Exhibit B - Sample Statement of Work
Exhibit C - Sample Interim Agreement
Exhibit D - Cambridge Software "Re-Use" Program

                                      10
<PAGE>
 
                               MASTER AGREEMENT
                                   EXHIBIT A
                               SAMPLE WORK ORDER


                                 WORK ORDER

This Work Order is issued pursuant to the Master Agreement for Professional
Services between CAMBRIDGE TECHNOLOGY PARTNERS ("Cambridge") and LIFELINE
SYSTEMS, INC. ("Client") dated ___________.

PROJECT NAME:
------------ 

SCOPE OF SERVICES:  Cambridge will provide the services described in the
-----------------                                                       
attached Statement of Work dated ___________.

START DATE:            END DATE:
-----------            -------- 

PRICE AND PAYMENT SCHEDULE:
-------------------------- 

          Service      Price      Payment Amount & Due Date
          -------      -----      -------------------------

BILLING ADDRESS:  refer to the Master Agreement.
---------------                                 

WARRANTY TERMS:
-------------- 

OTHER SPECIAL TERMS & CONDITIONS:
-------------------------------- 

RE-USE COMPONENTS:  The following software components are classified as
-----------------                                                      
"Components-In" or "Components-Out" as those terms are defined in the Master
Agreement -

     Components-In:   1.
     -------------     
                      2.


     Components-Out:  1.
     --------------     
                      2.


CAMBRIDGE TECHNOLOGY PARTNERS      CLIENT: LIFELINE SYSTEMS, INC.

By:__________________________       By:__________________________

Name:________________________       Name:________________________

Title:_______________________       Title:_______________________

                                      11
<PAGE>
 
                               MASTER AGREEMENT
                                   EXHIBIT B
                           SAMPLE STATEMENT OF WORK


                            PROJECT:  Project Name

This Statement of Work ("SOW") dated ___________ describes the services to be
performed by Cambridge Technology Partners ("Cambridge") for _________________
("Client"). The SOW is divided into the following four sections:

          A.  PROCESS - How Cambridge will perform the work

          B.  SCHEDULE - Start, end and checkpoint dates

          C.  CLIENT RESPONSIBILITIES - Client tasks, obligations, etc.

          D.  DELIVERABLES - Identifiable work product resulting from the
              services

A.  PROCESS
-----------

     1.
     2.
     3.
     ...


B.  SCHEDULE
------------
The service begins on _____________ and ends on ______________ for a total
duration of _________ weeks.

                                      12
<PAGE>
 
C.  CLIENT RESPONSIBILITIES
---------------------------
During this phase Client is responsible for -

     1.
     2.
     3.
     ...


D.  DELIVERABLES
----------------
At the completion of this phase, Cambridge delivers -

     1.
     2.
     3.
     ...

                                      13
<PAGE>
 
                               MASTER AGREEMENT
                                   EXHIBIT C
                           SAMPLE INTERIM AGREEMENT

CLIENT INFORMATION
------------------
Client:            ________________________________

Client Contact:           _____________________________________

Address:                  _____________________________________

Telephone No.:            _____________________________________


PROJECT INFORMATION
-------------------
Application Name:         _____________________________________

Phase/Service:     ________________________________

Weekly Billing Rate:      _____________________________________

Project Start Date:       _____________________________________

Cambridge Contact:        _____________________________________


TERMS & CONDITIONS
------------------
Cambridge Technology Partners ("Cambridge") and Client hereby enter into this
Interim Agreement ("Agreement") to reserve a Cambridge project team and allow
work to begin on Client's Application while Cambridge and Client resolve
outstanding project related issues.  Each party will use its best efforts to
resolve all issues in a timely manner and execute a formal contract document for
the services ("Contract").  Unless otherwise agreed by the parties in writing,
all software, source code, documentation, designs and other materials developed
by Cambridge under this Agreement shall constitute "Custom Software" as defined
in the Master Agreement dated ___________ between Cambridge and Client.

Cambridge will begin work on the Project Start Date and will bill Client at the
Weekly Billing Rate plus travel and living expenses.  Cambridge will invoice
Client in two week increments beginning on the Project Start Date.  Each payment
shall be due within 10 days of Client's receipt of the invoice.  The Contract,
once in place, will supersede this Agreement and all payments 

                                      14
<PAGE>
 
made under this Agreement will be applied to the price specified in the
Contract. Client may cancel this Agreement at any time by providing Cambridge
with two weeks written notice. In the event Client does terminate, the Weekly
Billing Rate will be prorated through the end of the two-week notice period.

This Agreement, once signed, should be forwarded to the Client Contact
identified above and a copy faxed to Cambridge Technology Partners at (617) 374-
2007.


CAMBRIDGE TECHNOLOGY PARTNERS      CLIENT: LIFELINE SYSTEMS, INC.

By:__________________________      By:___________________________

Name:________________________      Name:_________________________

Title:_______________________      Title:________________________

                                      15
<PAGE>
 
                               MASTER AGREEMENT
                                   EXHIBIT D
                       CAMBRIDGE SOFTWARE RE-USE PROGRAM


1.  WHAT IS CAMBRIDGE SOFTWARE RE-USE
-------------------------------------

Cambridge uses the technique of "Software Re-Use" whenever the Client agrees it
is the most cost-effective development approach.  Cambridge defines Software Re-
Use as "using a pre-existing software component as a building block when
developing a customized software application".

The Cambridge Software Re-Use Program has the following benefits for the Client:

  a)  Shorter Delivery Time than would be possible if every line of code were
      ---------------------                                                  
written from scratch.

  b)  Greater Software Reliability because the pre-existing software has already
      ----------------------------                                              
been used and tested.

  c)  Greater Potential for Subsequent Re-Use by the Client because the finished
      -----------------------------------------------------                     
      software delivered to the Client is designed and developed with Software
      Re-Use in mind.

  d)  Free "Re-Usable Component" Updates for One Year.  Cambridge continues to
      -----------------------------------------------                         
      improve Components as they are used in other projects. For a period of one
      year after the Client's development is complete, Cambridge provides the
      Client with any update releases to those reusable software components.
      This free service includes updates to both the re-usable components
      created during development as well as the re-usable components Cambridge
      brings to the development effort.

2.  CAMBRIDGE SOFTWARE RE-USE TERMINOLOGY
-----------------------------------------

  a)  Third Party Software Components - Any pre-existing software owned by a
      -------------------------------                                       
      third party and used in developing the Client software application. Third
      Party Software is typically licensed directly between the Third Party and
      the Client. Cambridge will not use Third Party Software in connection with
      the performance of services for Client without the written consent of
      Client.

  b)  Cambridge Components-In - Any pre-existing Cambridge software (or software
      -----------------------                                                   
      developed by Cambridge staff not directly involved in the Client's
      project) which is used by 

                                      16
<PAGE>
 
      Cambridge as a development building block in the Client's software
      application. Components-In are owned by Cambridge.

  c)  Cambridge Components-Out - Re-usable software components created during
      ------------------------                                               
      development of the Client's software application.  A component will be
      defined as a "Component-Out" only when the Client has agreed in writing to
      classify it as a Component-Out.

  d)  Custom Software - All software developed and delivered by Cambridge
      ---------------                                                    
      excluding the Third Party Software, Cambridge Components-In, and 
      ---------
      Cambridge-Components-Out. The Client retains ownership of the Custom
      Software, and Cambridge shall retain no rights therein.

3. PROCESS FOR IDENTIFYING "COMPONENTS-IN" AND "COMPONENTS-OUT"
----------------------------------------------------------------
All Components-In and Components-Out will be identified on individual Work
Orders.  Since it is often not possible to identify all components until after a
Work Order has been signed and the project underway, the component list can be
amended any time by a Change Order signed by both Cambridge and Client.
Software will not be included in the Re-Use Program without the Client's written
consent.

4.  NO "COMPONENTS-IN" OR "COMPONENTS-OUT"
------------------------------------------
For purposes of this Agreement, no components will be classified as Cambridge
Components-In or Cambridge Components-Out.  In the event the parties agree to
amend this Agreement to provide for "Components-In" or "Components-Out", this
Agreement will also be amended to provide for mutually agreeable license terms
relating thereto.

                                      17
<PAGE>
 
                               MASTER AGREEMENT

                         [NEXTGEN PROJECT] WORK ORDER


                                 WORK ORDER

This Work Order is issued pursuant to the Master Agreement for Professional
Services between CAMBRIDGE TECHNOLOGY PARTNERS ("Cambridge") and LIFELINE
SYSTEMS, INC. ("Client") dated ___________.

PROJECT NAME: NextGen
------------         

SCOPE OF SERVICES:  Cambridge will provide the services described in the
-----------------                                                       
attached Statement of Work dated [July 24], 1997, as amended from time to time.

START DATE:                END DATE:
-----------                -------- 

PRICE AND PAYMENT SCHEDULE:
-------------------------- 

          Service      Price      Payment Amount & Due Date
          -------      -----      -------------------------

BILLING ADDRESS:  refer to the Master Agreement.
---------------                                 

WARRANTY TERMS:  The additional warranty provisions applicable to the work
--------------                                                            
described in the attached Statement of Work are as follows:

(a)  The warranty period (the "Warranty Period") shall be 30 days following
     Client's acceptance of the Deliverables.  The warranty is subject to Client
     maintaining a support agreement with Cambridge for the duration of the
     Warranty Period.

(b)  Cambridge will make trained software engineers familiar with the
     Deliverables and Client's system available by telephone 24 hours per day, 7
     days per week, during the Warranty  Period, to respond to Client's
     emergency inquiries concerning the operation of the Deliverables, at no
     charge to Client.

(c)  The level of effort required of Cambridge with respect to Errors in the
     Deliverables which have been reported by Client to Cambridge during the
     Warranty Period is as follows:

     (1)  "Critical Errors" are Errors that cause Client's system or one of its
          substantial components to malfunction to a degree that a subscriber
          call is lost and/or the "Essential Information" required to service a
          subscriber properly is unavailable or improperly recorded.  "Essential
          Information" means information required to receive a call, determine
          if it is a "help needed" call, and, if so, to properly assist the
          subscriber in his/her emergency.  If a 

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<PAGE>
 
          Critical Error occurs, Cambridge will immediately dispatch personnel
          familiar with the Deliverables and Client's system to Client's
          facilities to correct such Critical Error, and will work without
          interruption, using all necessary resources, until such Critical Error
          is corrected.

     (2)  "Severe Errors" are Errors that cause Client's system or one of its
          substantial components to abend, but do not cause the loss of a call
          or prevent Essential Information from reaching a call monitor, or that
          create a significant increase in call response time.  If a Severe
          Error causes more than one call monitor to abend, then it will be
          upgraded to a Critical Error.  If a Severe Error occurs, Cambridge
          will dispatch personnel familiar with the Deliverables and Client's
          system to Client's facilities on the next business day to correct such
          Severe Error, and will work during normal business hours, using
          reasonable resources, until such Severe Error is corrected.

     (3)  "Moderate Errors" are Errors that do not result in a system abend, but
          do create an invalid representation of non-essential information.
          Moderate Errors include report errors.  Cambridge will use reasonable
          efforts to correct Moderate Errors as soon as practicable.

     (4)  "Minor Errors" are Errors not related to the functionality of the
          Deliverables, or which are cosmetic.  Cambridge will use reasonable
          efforts to correct Minor Errors within a commercially reasonable time
          frame.

OTHER SPECIAL TERMS & CONDITIONS:
-------------------------------- 

RE-USE COMPONENTS: No software components are classified as "Components-In" or
-----------------                                                             
"Components-Out" as those terms are defined in the Master Agreement.


CAMBRIDGE TECHNOLOGY PARTNERS      CLIENT: LIFELINE SYSTEMS, INC.

By:___________________________     By:____________________________

Name:_________________________     Name:__________________________

Title:________________________     Title:_________________________

                                      19
<PAGE>
 
                               MASTER AGREEMENT
                           SAMPLE STATEMENT OF WORK


                               PROJECT: Nextgen


This Statement of Work ("SOW") dated ____________ describes the services to be
performed by Cambridge Technology Partners ("Cambridge") for Lifeline Systems,
Inc. ("Client"). The SOW is divided into the following four sections:

          A.  PROCESS - How Cambridge will perform the work
          B.  SCHEDULE - Start, end and checkpoint dates
          C.  CLIENT RESPONSIBILITIES - Client tasks, obligations, etc.
          D.  DELIVERABLES - Identifiable work product resulting from the
                             services

A.  PROCESS
-----------

     1.
     2.
     3.
     ...


B.  SCHEDULE
------------
The service begins on ___________ and ends on ____________ for a total duration
of _________ weeks.

                                      20
<PAGE>
 
C.  CLIENT RESPONSIBILITIES
---------------------------
During this phase Client is responsible for -

     1.
     2.
     3.
     ...


D.  DELIVERABLES
----------------
At the completion of this phase, Cambridge delivers -

     1.
     2.
     3.
     ...

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