FMS's Green Book

Financial Management Service (FMS) of the U.S. Department of the Treasury publishes a comprehensive guide for financial institutions that receive Automated Clearing House (ACH) payments from the Federal government, and send payments (i.e. collections) to the Federal government. This guide, titled Green Book--A Guide to Federal ACH Payments and Collections or simply the Green Book, is designed to deal primarily with exceptions or issues unique to Federal government operations. Information on how to download a free copy of the Green Book is below.

Also, FMS encourages you to visit their web site for updates and news relevant to Federal government ACH transactions.
FMS Website

Green Book:
A Guide to Federal ACH Payments and Collections

Sections in this text cover how to enroll in the ACH, processing payments, returns, what do to in the event of non-receipt, and how people will be notified of changes in the ACH system. The Green Book also includes contact information and a glossary for the benefit of users. New editions are periodically issued by the Treasury and are posted online for easy reference.

Click button to be taken to a download page on the FMS website where you can download the full publication or each chapter seperately.