ACH Message Structure

An ACH message has the following record structure:

• File Header record
  • Batch Header

    Entry Detail record

    Addenda (Optional)

  • Batch Trailer record
• File Trailer record

All ACH records have the following properties:

• Have positional syntax.
• Are 94 bytes in length for every type of record.
• Start with a two-byte fixed string.
• Consist of six types of records.

For additional information on the record formats of all transactions including IAT, refer to the NACHA web site http://www.achrulesonline.org.

Each record type, file header, entry detail, and so forth, contain a fixed code called Record Type Code. This code is present in all record types in the following list:

Record Type

Description

01

File Header record (contains originator or receiver information)

05

Batch Header record (contains trading partner account information)

06

Entry Detail record (contains individual payment information)

07

Addenda record (contains 80 characters of payment related additional information). Optional.

08

Batch Trailer record (closes the batch for the corresponding 05)

09

File Trailer record (closes the ACH file for the corresponding 01)

99

Filler (added to keep the ACH message in multiples of 10 for each block)

The IAT entry is handled by the ACH Envelope, ACH Deenveloping, and ACH Return Generation services. This entry is treated in the same way as other ACH entries, and the inbound and outbound envelopes are created before the Sterling B2B Integrator processes them.