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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




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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:  1.
    
    Credit Agreement Governs.Except as set forth in this Agreement, New
Revolving Loans shall otherwise be subject to the provisions of the
Credit Agreement and the other Credit Documents. The obligations of each Credit Party
hereunder and under the new Revolving Loan Note issued in connection herewith
constitute Obligations under the Credit Agreement.2.
    
    Companys Certifications.By his or her execution of this Agreement,
the undersigned officer of Company, to the best of his or her knowledge,
hereby certifies in the name and on behalf of the Company as follows:  i.
    
    The representations and warranties contained
in the Credit Agreement and the other Credit Documents are
true and correct in all material respects on and as of the
date hereof to the same extent as though made on and as of
the date hereof, except to the extent such representations
and warranties specifically relate to an earlier date, in
which case such representations and warranties were true and
correct in all material respects on and as of such earlier
date;ii.
    
    No event has occurred and is continuing or
would result from the consummation of the transactions
contemplated hereby that would constitute a Default or an
Event of Default; andiii.
    
    Company has performed in all material
respects all agreements and satisfied all conditions which
the Credit Agreement provides shall be performed or
satisfied by it on or before the date hereof.  3.
    
    Company Covenants.By its execution of this Agreement, Company hereby
covenants that:  i.
    
    Company shall make any payments required
pursuant to Section 2.16(c) of the Credit Agreement in
connection with the New Revolving Loan Commitment; 2 of 8




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ii.
    
    Company shall deliver or cause to be delivered
the following legal opinions and documents: a new Revolving
Loan Note in favor of Increasing Lender and an opinion of
Fried, Frank, Harris, Shriver & Jacobson LLP, counsel to the
Credit Parties, together with all other documents reasonably
requested by Administrative Agent in connection with this
Agreement; andiii.
    
    Set forth on the attached Officers
Certificate are the calculations (in reasonable detail)
demonstrating compliance with the financial tests described
in Section 6.8 of the Credit Agreement.  4.
    
    Recordation of the New Loans.Upon execution and delivery hereof,
Administrative Agent will record the New Revolving Loans and New
Revolving Loan Commitment made by Increasing Lender in the Register.5.
    
    Amendment, Modification and Waiver.This Agreement may not be amended,
modified or waived except by an instrument or instruments in writing
signed and delivered on behalf of each of the parties hereto.6.
    
    Entire Agreement.This Agreement, the Credit Agreement and the other
Credit Documents constitute the entire agreement among the parties with respect
to the subject matter hereof and thereof and supersede all other prior
agreements and understandings, both written and verbal, among the parties or any of them
with respect to the subject matter hereof.7.
    
    GOVERNING LAW. THIS AGREEMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HEREUNDER SHALL BE
GOVERNED BY, AND SHALL BE CONSTRUED AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK
(INCLUDING SECTION 5-1401 AND SECTION 5-1402 OF THE GENERAL OBLIGATIONS LAW OF THE STATE OF NEW YORK).8.
    
    Severability.Any term or provision of this Agreement which is invalid
or unenforceable in any jurisdiction shall, as to that jurisdiction, be
ineffective to the extent of such invalidity or unenforceability without rendering
invalid or unenforceable the remaining terms and provisions of this Agreement or
affecting the validity or enforceability of any of the terms or provisions of this
Agreement in any other jurisdiction. If any provision of this Agreement is so
broad as to be unenforceable, the provision shall be interpreted to be only so broad as
would be enforceable.9.
    
    Counterparts.This Agreement may be executed in counterparts, each of
which shall be deemed to be an original, but all of which shall constitute one
and the same agreement. 3 of 8




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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. CIT LENDING SERVICES CORPORATIONBy:
    
    /s/ Nicholas D efABRizioName:
    
    Nicholas D efABRizioTitle:
    
    V. P.IPC ACQUISITION CORP.By:
    
    /s/ John McSherryName:
    
    John McSherryTitle:
    
    SecretaryIPC INFORMATION SYSTEMS, LLCBy:
    
    /s/ John McSherryName:
    
    John McSherryTitle:
    
    SecretaryV BAND CORPORATIONBy:
    
    /s/ John McSherryName:      John McSherryTitle:       SecretaryIPC INFORMATION SYSTEMS FAR EAST INC.By:
    
    /s/ John McSherryName:     John McSherryTitle:       Secretary
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IPC INFORMATION SYSTEMS HOLDINGS, INC.By:
    
    /s/ John McSherryName:      John McSherryTitle:        SecretaryIPC INFORMATION SYSTEMS HOLDINGS USA, INC.By:
    
    /s/ John McSherryName:     John McSherryTitle:       SecretaryIPC INFORMATION SYSTEMS SERVICES, INC.By:
    
    /s/ John McSherryName:     John McSherryTitle:       SecretaryIPC INFORMATION SYSTEMS HOLDINGS, L.L.C.By:
    
    /s/ John McSherryName:     John McSherryTitle:       SecretaryIPC INFORMATION SYSTEMS HOLDINGS USA, L.L.C.By:
    
    /s/ John McSherryName:     John McSherryTitle:       Secretary
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IPC INFORMATION SYSTEMS SERVICES, L.L.C.By:
    
    /s/ John McSherryName:     John McSherryTitle:       SecretaryGAINS ACQUISITION CORP.By:
    
    /s/ John McSherryName:     John McSherryTitle:       SecretaryIPC NETWORK SERVICES, INC.By:
    
    /s/ John McSherryName:     John McSherryTitle:       SecretaryIPC FUNDING CORP.By:
    
    /s/ John McSherryName:     John McSherryTitle:       Secretary
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Consented to by: GOLDMAN SACHS CREDIT PARTNERS L.P.,
as Sole Lead Arranger and Syndication Agent By:
    
    /s/ Stephen KingName: Stephen KingTitle: Authorized Signatory
 GENERAL ELECTRIC CAPITAL CORPORATION
as Administrative Agent and Collateral Agent By:
    
    /s/ Raymond N. ShuName: RAYMOND N. SHUTitle: DULY AUTHORIZED SIGNATORY
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SCHEDULE A
TO JOINDER AGREEMENT Name of Lender
    
    Type of Commitment
    
    AmountCIT Lending Services
Corporation
    
    New Revolving Loan
Commitment
    
    $
    10,000,000($20,000,000
aggregate
Revolving Commitment)
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