SUPPLEMENT TO REVOLVING LINE OF CREDIT AGREEMENT
AMENDED AND RESTATED

The following constitutes the special provisions and/or special covenants and/or
modifications  referred  to in that  Revolving  Line of Credit  Agreement  dated
August 31, 1994 (the  "Credit  Agreement")  covering  the Loans (as that term is
defined in the Credit Agreement) of the undersigned (the "Borrower") from Mellon
Bank, N.A. ("Bank").

The following shall supersede any special provision or covenant contained in any
prior  Supplement to Revolving Line of Credit  Agreement and shall be applicable
to all Loans in existence on the date hereof or incurred hereafter.

1. The provisions of this Supplement  shall, as of the date hereof, be deemed to
be fully  incorporated by reference in, constitute a part of, and supplement the
provisions of, the Credit Agreement, which, except as supplemented hereby, shall
continue in full force and effect in accordance with its terms and conditions.

2.  Borrower  hereby  covenants  and  agrees  that,  so  long as any  Loans  are
outstanding, Borrower shall, except as Bank may grant its prior written consent:

A.  Furnish  to  Bank,  within  90 days  after  the end of each  fiscal  year of
Borrower,  a financial  statement of  Borrower's  profit and loss and surplus of
such fiscal year and a balance  sheet as of the end of such fiscal year, in each
case  setting  forth in  comparative  form  the  corresponding  figures  for the
preceding  fiscal year,  all in reasonable  detail and audited by an independent
certified  public  accountant not  unsatisfactory  to Bank, and certified by the
principal financial officer of Borrower.

B.  Provide  within 45 days from the end of each  quarter an internal  financial
statement of Borrowers profit and loss and a balance sheet as of the end of such
period, in each case setting forth in comparative form corresponding figures for
the preceding like period, all in reasonable detail. Borrower to also furnish to
Bank,  within 45 days from the end of each quarter,  a report,  as of the end of
the preceding fiscal quarter,  containing  Borrower's  accounts receivable aging
and a  description  of raw material and finished  goods  inventory,  including a
listing  of  eligible  Accounts  Receivable  and  eligible  Inventory,   all  in
reasonable detail and in form and content satisfactory to Bank.

C.  Furnish  to Bank a copy of  Form(s)  10-K  and  10-Q  when  provided  to the
Securities and Exchange Commission.

D.  Maintain at all times a ratio of Borrower's total  liabilities  to tangible
net worth (as defined by GAAP) of not more than 1 to 1.

For  purposes of this  agreement,  Tangible  Net Worth shall mean  stockholder's
equity in Borrower less treasury stock and less all items properly classified as
intangible,  as determined  in accordance  with  generally  accepted  accounting
principles consistently applied.

E. Maintain  minimum net income from  continuing  operations of $5OO,OOO,  to be
measured on a rolling four quarter basis.  First measurement will be the quarter
ending 12/31/97. This net income covenant will exclude the following:

- Exclude impact of discontinued operation in Fremont, California.
- Exclude impact of benefit from possible tax refunds due to operating loss.

F. Not permit the  outstanding  balance and accrued  but unpaid  interest  under
Borrower's Line of Credit  extended  pursuant to the term hereof (The Revolving
"Line of Credit") to exceed an amount equal to the sum of 80% of the outstanding
dollar amount of Borrower's Eligible Accounts (as defined below) plus 20% of the
outstanding  dollar amount of Borrower's  Eligible Inventory (as defined below),
however  that at no time shall the portion of loans based on Eligible  Inventory
exceed $5 million.

"Eligible Accounts"' means United States accounts, and Canadian accounts aged 90
days or less, created or acquired by Borrower in the ordinary course of business
which are and at all times  continue to be  acceptable to Bank and in which Bank
has a prior security interest at all times.

"Eligible Inventory" shall mean all raw materials and finished goods.

Borrower agrees and  acknowledges  that Bank, at its sole  discretion,  may lend
additional  amounts to Borrower in excess of the limitations set forth above and
may,  upon an event of  default  as  defined  in the  Revolving  Line of  Credit
Agreement,  change the  percentage  loan limit of  Eligible  Accounts  set forth
above.

If the  outstanding  principal  balance  and  accrued  but  unpaid  interest  on
Borrower's  Line of Credit  shall at any time exceed the limit set forth  above,
then  Borrower  shall,  upon  Bank's  request,  pay  immediately  to  Bank  such
additional  collateral  security  as  Bank  in  its  sole  discretion  may  deem
appropriate.

G. Not incur,  create,  assume or permit to exist ' any pledge,  lien, charge or
other encumbrance of any nature whatsoever on any of its accounts receivable and
inventory, now or hereafter owned, other then (I) such encumbrances reflected in
the most recent financial  statement of Borrower submitted to Bank prior hereto,
(ii)  security  interests  granted in favor of Bank,  (iii)  pledges or deposits
under workers' compensation, unemployment insurance and social security laws, or
to secure  the  performance  of bids,  tenders,  contracts  (other  than for the
repayment of borrowed  money) or leases or to secure  statutory  obligations  or
surety or other similar bonds used in the ordinary course of business,  (iv) tax
liens which are being  contested  in good faith and by  appropriate  proceedings
diligently  conducted  (unless  and  until  foreclosure,  sale or other  similar
proceedings  have  been  commenced)  and  provided  that such  reserve  or other
appropriate  provisions,  if any,  as shall be required  by  generally  accepted
accounting  principles  shall  have been made  therefore,  and (v) any  unfilled
materialmen's,  mechanic's,  workmen's and repairman's liens (provided,  that if
such a lien shall be perfected,  it shall be discharged of record immediately by
payment, bond or otherwise).

Regulation U: The borrower  hereby  represents and warrants that it will make no
borrowings  hereunder for the purpose of buying or carrying any "margin  stock",
as such term is used in  Regulation U of the board of  governors of  the federal
reserve  system,  as amended  from time to time.  Neither the  Borrower  nor any
subsidiary owns any "margin  stock".  Neither the borrower nor any subsidiary is
engaged in the business of extending  credit to others for such purpose,  and no
part of the  proceeds  of any  borrowing  hereunder  will be used to purchase or
carry any  "margin  stock" or to extend  credit  to others  for the  purpose  of
purchasing or carrying any "margin stock".

SIGNATURES

Witness the due execution  hereof intending to be legally bound this 30th day of
December, 1997.

Attest:

By: /s/ Joseph E. Zavacky
Controller & Assistant Secretary

C-COR Electronics, Inc.

By:  /s/ Chris A. Miller
Vice President - Finance, Secretary
& Treasurer

Mellon Bank, N.A.
P.O. Box 1010
10 S. 2nd Street
Harrisburg, PA  17101

By: /s/ Milton S. Hefft