PSC INC. AND SUBSIDIARIES
DECEMBER 31, 2001

Exhibit 10.56

As
of April 3, 2002

JOHN
HANCOCK LIFE INSURANCE COMPANY
JOHN HANCOCK VARIABLE LIFE INSURANCE COMPANY
200 Clarendon Street
Boston, Massachusetts 02117

THE
LINCOLN NATIONAL LIFE INSURANCE COMPANY
LINCOLN NATIONAL INCOME FUND, INC.
c/o Delaware Lincoln Investment Advisors
200 East Berry Street
Renaissance Square
Ft. Wayne, Indiana 46802

SECURITY-CONNECTICUT
LIFE INSURANCE COMPANY
c/o ING Investment Management LLC
100 Washington Avenue South
Suite 800
Minneapolis, Minnesota 55401

THE
EQUITABLE LIFE ASSURANCE SOCIETY OF THE UNITED STATES
c/o Alliance Capital Management L.P.
1345 Avenue of the Americas, 37th Floor
New York, New York 10105



Ladies
and Gentlemen:

PSC INC.,
a New York corporation (the "Holding Company"), and PSC SCANNING, INC., a Delaware corporation and a Wholly-Owned Subsidiary of the Holding Company (the "Operating
Company") (the Holding Company and the Operating Company are sometimes collectively referred to herein as the "Companies" and each as a "Company"), jointly and severally agree with you as follows:

1.Definitions; Background.



2.Amendments to Second Amendment.The Companies have requested that the holders of the Notes extend the Waiver
Period under the Second Amendment. On the basis of the information provided to the holders of the Notes by the Companies in connection herewith, and subject to the

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terms and conditions hereof, such holders by their execution hereof agree with the Companies that the Second Amendment is hereby amended:



3.Conditions Precedent to Effectiveness.The provisions of this Letter Agreement shall be effective as of the
date on which each of the following conditions shall have been fulfilled:



4.Ratification, etc.



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5.Governing Law.This Letter Agreement, including the validity hereof and the rights and obligations of the
parties hereunder, shall be construed in accordance with and governed by the domestic substantive laws of the State of New York without giving effect to any choice of law or conflicts of law provision
or rule that would cause the application of the domestic substantive laws of any other jurisdiction.

6.Miscellaneous.The headings in this Letter Agreement are for purposes of reference only and shall not limit
or otherwise affect the meaning hereof. This Letter Agreement embodies the entire agreement and understanding among the parties hereto and supersedes all prior agreements and understandings relating
to the subject matter hereof. In case any provision in this Letter Agreement shall be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining provisions shall not
in any way be affected or impaired thereby. This Letter Agreement may be executed in any number of counterparts and by the parties hereto on separate counterparts but all such counterparts shall
together constitute but one and the same instrument.

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remainder of this page is intentionally left blank.]

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If
you are in agreement with the foregoing, please sign the form of agreement on the accompanying counterpart hereof, whereupon this Letter Agreement shall become a binding agreement
under seal among the parties hereto. Please then return one of such counterparts to the Companies.

| |  | Very truly yours, 
| |  | ------------------
| |  | PSC INC.          
| |  | By:               
| |  | PSC SCANNING, INC.
| |  | By:               

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Each
of the undersigned (a) acknowledges and assents to the terms and provisions of the foregoing Letter Agreement and
(b) ratifies and confirms each of the Operative Documents to which it is a party and agrees that each such Operative Document is in full force
and effect, that its obligations thereunder are its legal, valid and binding obligations enforceable against it in accordance with the terms thereof and that it has no defense, whether legal or
equitable, setoff or counterclaim, to the payment and performance of such obligations.

| |  | INSTAREAD CORPORATION                                      
| |  | -----------------------------------------------------------
| |  | By:                                                        
| |  | PSC AUTOMATION, INC. (formerly named Lazerdata Corporation)
| |  | By:                                                        
| |  | PERCON INCORPORATED                                        
| |  | By:                                                        
| |  | PSC BELGIUM, INC.                                          
| |  | By:                                                        

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|The foregoing is hereby accepted and agreed to: |                                                                                                        | 
|----------------------------------------------- | ------------------------------------------------------------------------------------------------------ | 
|JOHN HANCOCK LIFE INSURANCE COMPANY             |                                                                                                        | 
|By:                                             | (Title)                                                                                                | 
|The foregoing is hereby accepted and agreed to: |                                                                                                        | 
|JOHN HANCOCK VARIABLE LIFE INSURANCE COMPANY    |                                                                                                        | 
|By:                                             | (Title)                                                                                                | 
|The foregoing is hereby accepted and agreed to: |                                                                                                        | 
|THE LINCOLN NATIONAL LIFE INSURANCE COMPANY     |                                                                                                        | 
|By:                                             | Delaware Lincoln Investment Advisers, a series of Delaware Management Business Trust, Attorney-in-Fact | 
|By:                                             | (Title)                                                                                                | 
|The foregoing is hereby accepted and agreed to: |                                                                                                        | 
|LINCOLN NATIONAL INCOME FUND, INC.              |                                                                                                        | 
|By:                                             | (Title)                                                                                                | 
|                                                |                                                                                                        | 

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|The foregoing is hereby accepted and agreed to:           |                                         | 
|--------------------------------------------------------- | --------------------------------------- | 
|SECURITY-CONNECTICUT LIFE INSURANCE COMPANY               |                                         | 
|By:                                                       | ING Investment Management LLC, as Agent | 
|By:                                                       | (Title)                                 | 
|The foregoing is hereby accepted and agreed to:           |                                         | 
|THE EQUITABLE LIFE ASSURANCE SOCIETY OF THE UNITED STATES |                                         | 
|By:                                                       | (Title)                                 | 

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