EX-10.17: JOINDER AGREEMENT

Execution Copy

Exhibit 10.17

JOINDER AGREEMENT
(Existing Lender)

               THIS JOINDER AGREEMENT, dated as of April 20, 2004 (this “Agreement”), is by and among CIT LENDING SERVICES CORPORATION (“Increasing Lender”), IPC ACQUISITION CORP., a Delaware corporation (“Company”), CERTAIN SUBSIDIARIES OF THE COMPANY, as guarantors, GOLDMAN SACHS CREDIT PARTNERS L.P., as sole Lead Arranger and as Syndication Agent (“GSCP”), and GENERAL ELECTRIC CAPITAL CORPORATION, as Administrative Agent and as Collateral Agent (“GECC”).

RECITALS:

               WHEREAS, reference is hereby made to that certain AMENDED AND RESTATED CREDIT AND GUARANTY AGREEMENT, dated as of August 29, 2003 (as amended by that certain Amendment No. 1 to Amended and Restated Credit and Guaranty Agreement, dated as of December 12, 2003, and as the same may be further amended, restated, supplemented or otherwise modified from time to time, the “Credit Agreement”: the terms defined therein and not otherwise defined herein being used herein as therein defined), by and among the Lenders party thereto from time to time, GSCP, GECC and CIT LENDING SERVICES CORPORATION, as Documentation Agent;

               WHEREAS, subject to the terms and conditions of the Credit Agreement, Company may increase the existing Revolving Commitments by entering into one or more Joinder Agreements;

               WHEREAS, Increasing Lender was a party to the Credit Agreement on the Effective Date and has a Revolving Commitment in the amount of $10,000,000; and

               WHEREAS, at Company’s request, as of the date hereof and subject to the terms and conditions hereof, Increasing Lender has agreed to increase its Revolving Commitment by $10,000,000 (the “New Revolving Loan Commitment”) to $20,000,000.

               NOW, THEREFORE, in consideration of the premises and agreements, provisions and covenants herein contained, the parties hereto agree as follows:

     A. Increasing Lender hereby agrees to commit to provide the New Revolving Loan Commitment, as set forth on Schedule A annexed hereto, on the terms and subject to the conditions set forth below:

     Increasing Lender (i) confirms that it has received a copy of the Credit Agreement and the other Credit Documents, together with copies of the financial statements referred to therein and such other documents and information as it has deemed appropriate to make its own credit analysis and decision to enter into this Agreement; (ii) agrees that it

1 of 8

will, independently and without reliance upon the Administrative Agent or any other Lender or Agent and based on such documents and information as it shall deem appropriate at the time, continue to make its own credit decisions in taking or not taking action under the Credit Agreement; (iii) appoints and authorizes Administrative Agent and Syndication Agent to take such action as agent on its behalf and to exercise such powers under the Credit Agreement and the other Credit Documents as are delegated to Administrative Agent and Syndication Agent, as the case may be, by the terms thereof, together with such powers as are reasonably incidental thereto; and (iv) reaffirms that it will perform in accordance with their terms all of the obligations which by the terms of the Credit Agreement are required to be performed by it as a Lender.

     B. Increasing Lender hereby agrees to make the New Revolving Loan Commitment on the following terms and conditions:

2 of 8

3 of 8

               IN WITNESS WHEREOF, each of the undersigned has caused its duly authorized officer to execute and deliver this Joinder Agreement as of the date first written above.

4 of 8

5 of 8

6 of 8

Consented to by:

GOLDMAN SACHS CREDIT PARTNERS L.P.,
as Sole Lead Arranger and Syndication Agent

GENERAL ELECTRIC CAPITAL CORPORATION
as Administrative Agent and Collateral Agent

7 of 8

SCHEDULE A
TO JOINDER AGREEMENT

8 of 8