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                                                                   EXHIBIT 10.66

                          AMENDED OVERADVANCE LC RIDER

      This Amended Overadvance LC Rider is dated October 31, 2003, and is
attached to and forms a part of the Accounts Receivable Financing Agreement
dated as of June 13, 2003 (the "Accounts Agreement") between Proxim Corporation
("Borrower") and Silicon Valley Bank ("Bank"), and amends in its entirety the
prior Overadvance LC Rider to the Accounts Agreement effective on the date
hereof.

      1. Overadvance LCs.

         (a) Bank may, in its good faith business judgment, provide Borrower
with Letters of Credit in excess of the formulas set forth in the Accounts
Agreement (the "Overadvance LCs"), as set forth in this Rider. (If a Letter of
Credit is 100% secured by cash or is 100% reserved for from Advances which would
otherwise be available to the Borrower under the Accounts Agreement (after all
other reserves), such Letter of Credit will not be deemed an Overadvance LC. If
only part of the face amount of a Letter of Credit is secured by cash or is so
reserved, then such Letter of Credit shall only be deemed an Overadvance LC to
the extent such Letter of Credit is not cash secured and not covered by such
reserves.)

         (b) The unpaid balance of all Overadvance LCs from time to time
outstanding shall not at any time exceed $4,000,000, and in the event it does,
at any time, Borrower will provide Bank with cash collateral in an amount equal
to 100% of the excess immediately, without notice or demand.

         (c) In no event shall the total Obligations (including without
limitation the Overadvance LCs exceed $20,000,000.

      2. Overadvance Maturity Date.

         (a) Overadvance LCs may be outstanding only during the period from the
date hereof to the earlier of the following (the "Overadvance Maturity Date"):
October 31, 2003 or the date the Accounts Agreement terminates by its terms or
is terminated by any party in accordance with its terms.

         (b) On and after the Overadvance Maturity Date, the Overadvance
facility established by this Rider will expire, and no further Overadvance LCs
will be issued. On or before the Overadvance Maturity Date, Borrower shall
provide Bank with cash collateral in an amount equal to 100% of the face amount
of all outstanding Overadvance LCs (including without limitation drawn, but
unreimbursed Overadvance LCs). All cash collateral provided pursuant to this
Rider shall be held as "Collateral" for all purposes of the Accounts Agreement.
In the event, on the Overadvance Maturity Date, Borrower fails to provide Bank
with cash collateral in an amount equal to 100% of the face amount of all
outstanding Overadvance LCs, such failure shall constitute an Event of Default
under the Accounts Agreement.
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      3. Fees. Borrower shall pay all standard charges with respect to
Overadvance LCs as are charged by Bank's International Department. In addition,
Borrower shall pay Bank a fee in the amount of 1.5% per Week of the average
amount of Overadvance LCs outstanding during each Week, which shall be payable
on the last day of each Week. As used herein, "Week" means the seven-day period
beginning on the date of this Rider and each succeeding seven-day period. Said
fee shall be in addition to all interest and all other fees and charges, and may
be charged by Bank to any of Borrower's deposit accounts with Bank or to
Borrower's loan account.


      4. Collateral. The Obligation to reimburse Bank for all Overadvance LCs,
and all of Borrower's other obligations under this Rider shall for all purposes
be deemed "Obligations" under the Accounts Agreement and shall be secured by all
of the Collateral. All Overadvance LCs shall, for all purposes, be deemed to be
"Letters of Credit" under the Accounts Agreement, and all Overadvance LCs shall
be entitled to all of the benefits of, and (except as herein expressly set
forth) shall be subject to all of the terms and provisions of, all of the Loan
Documents.

Borrower:                                   Bank:

PROXIM CORPORATION                          SILICON VALLEY BANK


By /s/ David L. Thompson                       By (illegible)
  -----------------------------------             ------------------------------
      President or Vice President           Title
                                                  ------------------------------

By /s/ Richard J. Tellman
  -----------------------------------
      Secretary or Ass't Secretary




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