<PAGE>

                                                                  EXHIBIT 10(LL)

                            C-COR ELECTRONICS, INC.
                            Supplemental Retirement Plan


          1. Selection of Participants. This Plan is an unfunded non-qualified
arrangement for a select group of management and/or highly compensated employees
of C-COR Electronics, Inc. (hereinafter "Corporation"). Each employee selected
by Corporation for participation hereunder (hereinafter "Participant") shall
indicate his agreement to the terms of this Plan by executing a Participation
Agreement to be provided by Corporation.

          2. Definitions. Certain terms shall be defined hereunder as follows:

               a. "Beneficiary" means a person, persons, trust or trusts which a
     Participant shall, from time to time, designate in writing to receive any
     benefits payable to him under this Plan in the event of his death.

              b.  "Committee" means the Compensation Committee of the Board of
     Directors of Corporation.
              c.  "Disability" shall have the same meaning as the term is
     defined in Corporation's Long Term Disability Plan.
              d.     "Effective Date of Plan" means April 20, 1993.

              e.  "Supplement Retirement Benefit" means a benefit provided to a
     Participant if he elects to participate under the Plan and remains in
     corporation's employ until attaining the age specified in Section 3 of the
     Plan.

              f. (1)   "Participant" means a full-time employee working more
     than 2,000 hours per year.

              f. (2)   "Participant Status Requirement" means a participant who
     has been a participant in the Plan for five years, hired directly in the
     plan; or an employee who has been a participant in the Plan for three years
     by being promoted into the Plan and who has at least two additional years
     as an employee of C-Cor Electronics, Inc.

              g.  "Participant Agreement" means the Agreement signed by
     Participant that evidences his participation in the Plan.  A blank
     Participation Agreement is attached to this Plan and incorporated herein by
     this reference.

              h.  "Plan" means the Supplemental Retirement Plan of Corporation
     effective April 20, 1993, and as it may be amended from time to time by the
     Corporation.

              i.  "Plan Administrator" means Corporation.  Provided, however,
     that Corporation shall only be designated as Plan Administrator and named
     Fiduciary of the Plan for purposes of implementing the claims procedure
     contained in Paragraph 14, and for no other purpose.

              j.  "Survivor Benefit" means a benefit provided to Participant's
     Beneficiary if Participant elects to participate in the Plan and dies prior
     to commencement of the Supplemental Retirement Benefit while in the employ
     of Corporation.

             k.   "Death Benefit" means a benefit provided to Participant's
     Beneficiary if Participant elects to participate in the Plan and dies after
     commencement of the Supplemental Retirement Benefit.

              l.  "Year of Service" means a consecutive 12-month period during
     which an employee completes at least 2,000 hours of service with the
     Corporation.

          3.  Payments at Retirement.

              a.    Normal Retirement Date.    If a Participant continues in
     employment with corporation until he attains age 65 and 10 years of
     participant status, then, upon retirement, the Participant shall be
     entitled to receive from the Corporation a Supplemental Retirement Benefit
     in the amount specified in his Participation Agreement, payable in equal
     monthly installments, for a period of 15 years.  Such payments shall begin
     on the first day of the month following the Participant's attainment of his
     Normal Retirement Date.



          b.  Early Retirement.
              (1) If a Participant's employment with corporation terminates due
          to Early Retirement or Disability prior to his attainment of Normal
          Retirement Date but following his attainment of age 55 and ten (10)
          years of participant status, such Participant may retire before his
          Normal Retirement Date and receive early retirement benefits from the
          Plan.  The early retirement benefit shall be equal to the
<PAGE>

          actuarial equivalent of the Haneley Supplemental Retirement Benefit
          (as specified in the Participant's Agreement) commencing at the Normal
          Retirement Date. Such actuarial equivalent early retirement benefit
          shall be equal to the Supplemental Retirement Benefit multiplied by
          the early retirement factor set forth in Appendix A.

              (2) If a Participant's employment with the corporation terminates
          due to Early Retirement or Disability prior to his attainment of
          Normal Retirement Date but following his attainment of age 60 and
          attainment of participant status requirements, but less than ten (10)
          years of participant status, such Participant may retire before his
          Normal Retirement Date and receive early retirement benefits from the
          Plan.  This early retirement benefit shall be equal to the early
          retirement-benefit as calculated in Section 3,b, (l) and then
          multiplied by a benefit percentage factor for years of participant
          status less than ten (10) years as set forth in Appendix B.

              (3) The Early Retirement or Disability Benefit to which the
          Participant is entitled shall be paid in equal monthly installments
          for a period of 15 years.  Such payments shall begin on the first day
          of the month following the Participant's termination of employment.
          Provided, however, that no early retirement or disability benefit
          shall be payable under this Section 3.b. if the Participant has not
          satisfied the participant status requirement.  For calculating
          participant status, the Extended salary Plan of the Corporation,
          effective October 1, 1987, shall be a predecessor plan to this Plan.

          c.   Late Retirement.   If a Participant remains employed after the
     attainment of his Normal Retirement Date, such benefit shall not commence
     until he actually retires.  The amount of the Participant's late retirement
     benefit shall be equal to the actuarial equivalent of his Supplemental
     Retirement Benefit that would have commenced at his Normal Retirement Date.
     Such actuarial equivalent late retirement benefit shall be equal to the
     Supplemental Retirement Benefit multiplied by the late retirement factors
     set forth in Appendix C and payable in equal monthly installments for a
     period of 15 years.

          d.  Death Following Retirement.   If a Participant should die after
     payment of a Supplemental Retirement Benefit begins, but before receipt of
     the last of such payments, the remaining balance of such payments shall be
     paid on their due dates to the Participant's beneficiary designated in the
     Participant's Agreement or, failing such designation, to the Participant's
     estate.  As stated in Section 3.a., the total monthly payments of the
     Supplemental Retirement Benefit (for pre and post death) shall not exceed
     fifteen (15) years.

          4.  Other Termination of Employment or Participant Status Short of
     Required Participant Status.  If a Participant's employment with the
     Corporation terminates for any other reason (other than Death, Disability
     or Retirement), or a Participant has not met the participant status
     requirements, then he shall not be entitled to payment of a Supplemental
     Retirement Benefit under the Plan.

          5.  Survivor Benefits  (Pre-Retirement Death of Participant).
              (1) If an eligible Participant should die while in the
     Corporation's employment, and the Participant has become eligible for
     either Early, Normal, or Late Retirement, but before commencement of the
     Supplemental Retirement Benefit, such eligible benefit shall become payable
     to the Participant's beneficiary or, failing such designation, to the
     Participant's estate  Such benefit shall be paid in equal monthly
     installments, for a period of 15 years.  Such payments shall begin on the
     first day of the month following the Participant's death.

              (2) If a Participant should die while in the Corporation's
     employment, and the Participant has not become eligible for either Early,
     Normal, or Late Retirement, but has met the participant status
     requirements, the Participant's beneficiary or, failing such designation,
     the Participant' s estate, shall be entitled to a survivor benefit.  This
     survivor benefit shall be equal to the actuarial equivalent of the
     Supplemental Retirement Benefit commencing at Normal Retirement Date.  Such
     actuarial equivalent survivor benefit shall be equal to the Supplemental
     Retirement Benefit multiplied by the early retirement factors set forth in
     Appendix A and payable in equal monthly installments for a period of 15
     years.
<PAGE>

          6.  Status of Investments.   All investments made by Corporation under
     this Plan will be deemed made solely for the purpose of aiding Corporation
     in measuring and meeting its obligations under this Plan.  Corporation
     shall be the sole owner of all such investments and of all rights and
     privileges conferred by the terms of the instruments evidencing such
     investments.  Nothing stated herein will cause such investments to be
     treated as anything but the general assets of Corporation, nor will
     anything stated herein cause such investments to represent the vested,
     secured or preferred interest of any Participants or his Beneficiaries.

          7.  General Creditor Status.   A Participant shall have no claim with
     respect to any particular asset of Corporation, but shall be and shall
     remain at all times a general creditor of Corporation and, therefore, a
     Participant's rights under the Plan shall have not priority over the rights
     of any general creditor of Corporation.

          8.  No Assignment.   Neither a Participant nor his personal
     representative shall have any right to commute, sell, assign, transfer,
     encumber or otherwise dispose of the right to receive payments hereunder
     which payments and the right thereto are expressly declared to by non-
     assignable and non-transferable.  Any attempted assignment or transfer by a
     Participant or his personal representative shall be of no effect.
     Corporation shall have the right to assign this Plan and to transfer its
     obligations hereunder.

          9.  Revocation and Amendment.   This Plan may be amended or terminated
     at any time at the sole discretion of the Board of Directors of
     Corporation; provided, however, that any such amendment or termination
     shall not affect the rights of any Participant which may have accrued under
     the Plan at the time of amendment or termination.

         10.  No Employment Guarantee.   Nothing contained in this Plan shall be
     construed as conferring upon any Participant the right to continue in the
     employment of Corporation.

         11.  Authority of Committee.   The Committee shall have the full power
     and authority to interpret, construe and administer this Plan.  The
     Committee's interpretations and construction hereof and actions hereunder
     shall be binding and conclusive on all persons for all purposes.  No member
     of the Committee shall be liable to any person for any action taken or
     omitted in connection with the interpretation or administration of this
     Plan unless attributable to his own willful misconduct or lack of good
     faith.

         12.  Liability of the Corporation.   Nothing contained in the Plan or
     the Participation Agreement shall constitute the creation of a trust or
     other fiduciary relationship between Corporation and Participant or between
     Corporation and Beneficiary or any other person.  Corporation shall not be
     considered a trustee by reason of the existence of this Plan or the
     Participation Agreement.

         13.  Funding Assets.   Corporation reserves the absolute right in its
     sole and exclusive discretion either to fund the obligations of Corporation
     undertaken by this Plan or to refrain from funding the same, and to
     determine the extent, nature and method of such funding.  Should
     Corporation elect to fund this Plan, in whole or in part, through life
     insurance contracts, Corporation shall be the owner and beneficiary of each
     such policy.  Corporation reserves the absolute right, in its sole
     discretion, to terminate any such contract, as well as any other funding
     program, at any time, either in whole or in part.  Title to, and-beneficial
     ownership of, any assets which Corporation may earmark to pay the benefits
     hereunder shall at all times remain in Corporation.  Participant and
     Participant's Beneficiary shall not have any property interest whatsoever
     in any specific assets of Corporation.  Nothing set forth in this Plan
     shall cause such assets to be treated as anything but the general assets of
     Corporation.  If Corporation purchases life insurance contracts on the life
     of the Participant, Participant agrees to sign any applications that may be
     reasonably required for that purpose and to undergo any medical examination
     or tests which may be reasonably necessary in such regard.
<PAGE>

         14.   Claims Procedure.   In the event that benefits under paragraph 3
     or 5 of this Plan are not paid to the Participant or his Beneficiary, and
     such person feels entitled to receive them, a claim shall be made in
     writing to the Plan Administrator within 60 days from the date payments are
     not made.  Such claim shall be reviewed by the Plan Administrator.  If the
     claim is denied, in full or in part, the Plan Administrator shall provide a
     written notice within 90 days setting forth the specific reasons for
     denial, specific reference to the provisions of this Plan upon which the
     denial is based, and any additional material or information necessary to
     perfect the claim, if any.  Also, such written notice shall indicate the
     steps to be taken if a review of the denial is desired.

          If a claim is denied and a review is desired, the Participant shall
     notify the Plan Administrator in writing within 60 days (and a claim shall
     be deemed denied if the Plan Administrator does not take any action with
     the aforesaid 90 day period).  In requesting review, the Participant may
     review this Plan or any documents relating to it and submit any written
     issues and comments the Participant may feel appropriate.  In its sole
     discretion, the Plan Administrator shall then review the claim and provide
     a written decision within 60 days.  This decision likewise shall state the
     specific reasons for the decision and shall include specific reference to
     specific provisions of this Plan on which the decision is based.

         15.  Governing Law.   This Plan shall be governed by the laws of the
     Commonwealth of Pennsylvania.

         16.  Language.   Whenever used in this Plan, the singular number shall
     include the plural, the plural the singular and the use of any gender shall
     include all genders.

         17.  Effective Date.   This Plan shall be effective beginning April 20,
     1993.

                                         C-COR ELECTRONICS, INC.

                                         By:  David A. Woodle
                                             President and CEO

     Approved by C-COR Board of Directors on April 20, 1993.
<PAGE>

                                                                  April 20, 1993


                                   APPENDIX A

   NUMBER OF
 YEARS PRIOR TO                     EARLY RETIREMENT
NORMAL RETIREMENT                        FACTOR
     DATE

        1                                0.9145
        2                                0.8372
        3                                0.7670
        4                                0.7034
        5                                0.6456
        6                                0.5932
        7                                0.5454
        8                                0.5020
        9                                0.4625
        10                               0.4264
        11                               0.3935
        12                               0.3635
        13                               0.3360
        14                               0.3108
        15                               0.2877
        16                               0.2665
        17                               0.2471
        18                               0.2292
        19                               0.2127
        20                               0.1978
        21                               0.1836
        22                               0.1707
        23                               0.1588
        24                               0.1479
        25                               0.1377
        26                               0.1283
        27                               0.1196
        28                               0.1116
        29                               0.1041
        30                               0.0972
        31                               0.0908
        32                               0.0848
        33                               0.0793
        34                               0.0741
        35                               0.0694
<PAGE>

                   SOURCE:  MODIFIED UP-84 MORTALIY TABLE AT 625%





                                                                  April 20, 1993


                                   APPENDIX B

            NUMBER OF YEARS                             BENEFIT
            LESS THAN TEN YEARS                       PERCENTAGE
            OF PARTICIPANT STATUS

                   1                                      90%
                   2                                      80%
                   3                                      70%
                   4                                      60%
                   5                                      50%


SOURCE: BASED ON A STRAIGHT-LINE PERCENTAGE REDUCTION



                                                              April 20, 1993

                                   APPENDIX C

            NUMBER OF
           YEARS AFTER                             LATE RETIREMENT
        NORMAL RETIREMENT                             FACTOR
              DATE

                1                                     1.0817
                2                                     1.1714
                3                                     1.2700
                4                                     1.3787
            5 OR MORE                                 1.4986


                    SOURCE:  MODIFIED UP-84 MORTALITY TABLE AT 6.25%
<PAGE>

                                                                  "Attachment D"


                            C-COR ELECTRONICS, INC.
                          SUPPLEMENTAL RETIREMENT PLAN
                            PARTICIPATION AGREEMENT

          1.  I, the undersigned Participant. ("Participant"), hereby
     acknowledge receipt of a copy of the Supplemental Retirement Plan of C-COR
     Electronics, Inc. ("Corporation"), effective April 20, 1993 (the "Plan").
     By completion of this Agreement, I agree to comply with the terms of the
     Plan in all respects. I understand that all provisions of the Plan are
     hereby made a part of this Agreement.

          2.  In consideration of the foregoing and subject to the terms of the
     Plan, Corporation promises to pay the Supplemental Retirement Benefit
     therein described of $1500.00 per month.

          3.  Tax Advice.  I agree I have been advised by Corporation to consult
     my own tax advisors with respect to this Agreement and that neither
     Corporation nor its representatives have made or make any representation or
     warranties as to such consequences.

          4.  Insurance Policies.  I understand that Corporation may make
     application to purchase a life insurance policy or policies on my life,
     which will be owned by corporation and under which it will be the sole
     beneficiary.  I agree to provide Corporation with such information as it
     may require in order to make such application and to cooperate fully with
     Corporation in respect of such application, including the taking of a
     physical examination if requested to do so.  In this connection, I
     represent that my date of birth is 7/23/56.  In the event the insurance
     company to which application is made declines to issue the policy at
     standard premium rates, this Agreement will be void unless Corporation
     decides otherwise.  Similarly, if I should die prior to the date on which
     payment of the Supplemental Retirement Benefit commences and the proceeds
     of a policy on my life are not paid to Corporation because the information
     I have furnished in connection with the application is materially false or
     my death was caused by suicide within two (2) years of the date on the
     policy on my life issues, Corporation will be under no obligation to pay
     the Survivor Benefit herein provided.

          5.   No Employment Commitment.   Nothing in this Agreement shall be
     construed to imply any commitment on the part of Corporation to continue me
     in its employ.

          6.  Beneficiary.   I hereby designate the following person or persons
     as my beneficiary or beneficiaries under this Agreement.
     Mary Anne Hanelly.

     I reserve the right to change my beneficiary at any time and for any reason
     and without notice to or the consent of the beneficiary or beneficiaries,
     by delivering a writing to that effect to the office of the Secretary of
     Corporation or its successor.

          7.  Additional Conditions.

          8.  This Agreement shall be governed by the laws of the Commonwealth
     of Pennsylvania.

     Dated:  10/19/98  WTH

                                              William T. Hanelly
                                              Participant


                                              C-COR ELECTRONICS.
                                              By:  David A. Woodle


     4/20/93