Study guide
2.3 Entry Detail Record (Type 6) & Addenda Records (Type 7)
Nacha Accredited ACH Professional AAP
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1 Chapter 1: ACH Network Overview, Participants & Transaction Flow
1.1 ACH Network Structure, Governance & History 1.2 Five Key ACH Participants: Originator, ODFI, Operator, RDFI, Receiver 1.3 Third-Party Senders (TPS) and Third-Party Service Providers (TPSP) 1.4 End-to-End Transaction Flow, Clearing & Settlement Mechanics
2 Chapter 2: ACH File Architecture & Record Formatting
2.1 File Hierarchy: 94-Character Records, Blocking Factors & File Header (Type 1) 2.2 Company/Batch Header Record (Type 5) & Service Class Codes 2.3 Entry Detail Record (Type 6) & Addenda Records (Type 7) 2.4 Batch Control (Type 8), File Control (Type 9) & Entry Hash Calculations 2.5 Exception Record Formats: Return (Addenda 99) & Notification of Change (Addenda 98) Layouts
3 Chapter 3: Nacha Operating Rules Framework & Participant Warranties
3.1 Structure of Nacha Operating Rules, Rulemaking Process & Effective Dates 3.2 ODFI Warranties, Indemnifications & Participant Obligations 3.3 RDFI Warranties, Receipt Obligations & Statement Requirements 3.4 Nacha Return Rate Thresholds & Monitoring Requirements
4 Chapter 4: Standard Entry Class (SEC) Codes: Consumer Applications
4.1 PPD (Prearranged Payment and Deposit): Direct Deposit & Consumer Debits 4.2 WEB (Internet-Initiated Entries): Authorization, Authentication & Validation 4.3 TEL (Telephone-Initiated Entries): Inbound vs. Outbound Rules & Recording Requirements 4.4 CIE, MTE, POS & SHR: Machine and Point-of-Sale Consumer Entries 4.5 Same Day ACH: Windows, Limits ($1,000,000) & Eligibility Rules
5 Chapter 5: SEC Codes: Commercial, Check Conversion & Specialized Applications
5.1 CCD/CCD+ and CTX: Corporate Payments, Addenda & EDI / ASC X12 Formatting 5.2 Check Conversion SEC Codes: ARC, BOC & POP Rules and Notices 5.3 RCK (Re-presented Checks) & XCK (Destroyed Check Entries) 5.4 IAT (International ACH Transactions): Mandatory Addenda & OFAC Screening 5.5 Non-Monetary & Specialty Entries: Prenotifications, DNE & ENR
6 Chapter 6: Authorization Standards, Authentication & Record Retention
6.1 Fundamentals of Valid Authorization: Consumer vs. Commercial 6.2 E-SIGN Act Compliance, Electronic Signatures & Oral Authorizations 6.3 WEB Debit Account Validation Rule & Fraud Detection Systems 6.4 Authorization Retention (2 Years) & Copy Provision Rules
7 Chapter 7: Exception Processing: Returns & Return Reason Codes
7.1 Return Processing Overview: Two-Banking-Day Rule vs. Extended Return Rule 7.2 Administrative & Operational R-Codes (R01-R04, R08, R16, R17) 7.3 Unauthorized Consumer Returns: R05, R07, R10, R11 & The WSUD 7.4 Unauthorized Corporate Debits: R29, Contract Rights & the UCC Article 4A Boundary 7.5 Dishonored Returns (R61-R70) & Contested Dishonored Returns (R71-R76)
8 Chapter 8: Exception Processing: Notifications of Change (NOC) & Reversals
8.1 Notification of Change (NOC / COR): Structure & Change Codes (C01-C07) 8.2 NOC Timelines: RDFI Origination & Originator 6-Day Mandatory Action 8.3 Reversing Entries & Reversal Files: 5-Day Deadline & Erroneous Reasons 8.4 Federal Reclamation Procedures & Deceased Beneficiary Handling
9 Chapter 9: ACH Risk Management, Fraud Monitoring & Exposure Controls
9.1 ACH Risk Taxonomy: Credit, Operational, Fraud, Systemic & Compliance Risks 9.2 ODFI Originator Onboarding, Underwriting & Exposure Limits 9.3 Third-Party Sender (TPS) Due Diligence, Monitoring & Registration 9.4 Fraud Schemes: Business Email Compromise (BEC), Account Takeover & Controls 9.5 The 2026 Fraud Monitoring Rules: ODFIs, Originators, TPSPs & Third-Party Senders 9.6 RDFI ACH Credit Monitoring & the False Pretenses Definition 9.7 ACH Data Security: Article One, Sections 1.6 and 1.7 & the ACH Security Framework 9.8 Nacha's Risk Management Portal: Contact Registry, TPS & Direct Access Registration, Terminated Originator Database 9.9 ACH Risk Assessments, Regulatory Expectations & Operational Resilience
10 Chapter 10: Legal & Regulatory Framework for ACH
10.1 Regulation E (12 CFR 1005): Consumer Protections, Disclosures & Error Resolution 10.2 Uniform Commercial Code (UCC) Article 4A: Wholesale Funds Transfers & Security Procedures 10.3 BSA/AML, SAR/CTR Reporting & OFAC Sanctions Compliance in ACH 10.4 31 CFR Part 210 (The Green Book), Reg CC, Reg D & Reg J Interactions
11 Chapter 11: Nacha Rules Compliance Audit & National System of Fines
11.1 Annual ACH Rules Compliance Audit (Article One, §1.2.2): Scope & Requirements 11.2 Auditor Independence & 6-Year Audit Record Retention 11.3 National System of Fines: Complaint Process, Panel Review & Fine Classes 11.4 The Nacha Rules Effective-Date Calendar: 2026 Through 2028
12 Chapter 12: Alternative & Complementary Payment Systems
12.1 Fedwire Funds Service & CHIPS vs. ACH Network 12.2 Instant Payments: RTP and FedNow vs. Same Day ACH 12.3 Card Networks, Check 21 & Interoperability Across Payment Rails
2.3 Entry Detail Record (Type 6) & Addenda Records (Type 7)
Key Takeaways Explain This Topic AI
The Entry Detail Record (Type 6) conveys transaction instructions for an individual Receiver, containing account numbers, dollar amounts, routing numbers, and the 15-digit Trace Number.
Transaction Codes identify the target account type (Demand/Checking: 20s, Savings: 30s, General Ledger: 40s, Loan: 50s) and transaction direction (Debit, Credit, Prenote, Zero-Dollar Remittance).
The 15-digit Trace Number uniquely identifies each transaction, composed of the ODFI's 8-digit routing number (Positions 80–87) and a 7-digit ascending sequence number (Positions 88–94).
The Addenda Record Indicator (Position 79) is set to '1' when one or more Type 7 Addenda records follow, and '0' when no addenda record is present.
Addenda Records (Type 7) utilize standardized Addenda Type Codes (05 for standard payment-related info, 98 for NOC, 99 for Returns, 10–18 for IAT) and link to parent entries via the Entry Detail Sequence Number.
Last updated: August 2026
2.3 Entry Detail Record (Type 6) & Addenda Records (Type 7)
The core payment instruction in an ACH transmission is embodied in the Entry Detail Record (Type 6) . Each Type 6 record directs the transfer of funds into or out of an account at a Receiving Depository Financial Institution (RDFI), or transmits non-monetary account validation data.
When additional remittance, return, or international compliance information must accompany an entry, one or more Addenda Records (Type 7) are attached directly behind the Type 6 record.
Field-by-Field Specification: Entry Detail Record (Type 6)
The standard Type 6 record layout applies across consumer and corporate SEC codes (such as PPD , CCD , WEB , and TEL ), with specific SEC codes repurposing certain discretionary fields.
Field Positions Length Type Name Contents / Validation Rules
1 01–01 1 N Record Type Code Mandatory constant 6 . Identifies record as Entry Detail.
2 02–03 2 N Transaction Code 2-digit code identifying account type and payment direction (e.g., 22 , 27 , 23 , 28 , 32 , 37 , 42 , 47 , 52 , 57 ).
3 04–11 8 N Receiving DFI Identification The first 8 digits of the RDFI's Transit Routing Number. Used in Entry Hash calculation.
4 12–12 1 N Check Digit The 9th digit of the RDFI's Routing Number, calculated via Modulus 10 algorithm.
5 13–29 17 A/N DFI Account Number Receiver's account number at RDFI. Left-justified, blank-filled if under 17 characters.
6 30–39 10 N Amount Dollar amount in cents , zero-padded, right-justified (e.g., $1,250.75 is 0000125075 ). Zeroes ( 0000000000 ) for prenotes.
7 40–54 15 A/N Individual Identification Number Optional/Mandatory by SEC. Alphanumeric ID assigned by Originator (e.g., employee ID, customer account #, invoice #).
8 55–76 22 A/N Individual Name / Receiving Company Name 22 characters. Legal name of the Receiver whose account is debited or credited. Left-justified, blank-filled.
9 77–78 2 A/N Discretionary Data 2 characters. Optional data (in WEB entries, indicates 'R' for recurring or 'S' for single entry).
10 79–79 1 N Addenda Record Indicator 1 if one or more Type 7 Addenda records immediately follow; 0 if no addenda records follow.
11 80–94 15 N Trace Number Unique 15-digit identifier: Positions 80–87 = ODFI Routing # (8 digits); Positions 88–94 = 7-digit ascending sequence #.
Master Matrix of ACH Transaction Codes
Transaction Codes in Positions 02–03 dictate whether funds are credited or debited, designate the underlying account category, and identify non-monetary prenotifications. +-----------------------------------------------------------------------------------------+
- | NACHA TRANSACTION CODES |
- +---------------------+-------------------+---------------------+-------------------------+
- | Account Category | Live Credit ($) | Live Debit ($) | Prenote / Non-Dollar |
- +---------------------+-------------------+---------------------+-------------------------+
- | Demand / Checking | 22 (Credit) | 27 (Debit) | 23 (Prenote Credit) |
- | | | | 28 (Prenote Debit) |
- | | | | 24 (Zero-Dollar Remit) |
- +---------------------+-------------------+---------------------+-------------------------+
- | Savings Account | 32 (Credit) | 37 (Debit) | 33 (Prenote Credit) |
- | | | | 38 (Prenote Debit) |
- | | | | 34 (Zero-Dollar Remit) |
- +---------------------+-------------------+---------------------+-------------------------+
- | General Ledger (GL) | 42 (Credit) | 47 (Debit) | 43 (Prenote Credit) |
- | | | | 48 (Prenote Debit) |
- | | | | 44 (Zero-Dollar Remit) |
- +---------------------+-------------------+---------------------+-------------------------+
- | Loan Account | 52 (Credit) | 57 (Debit - | 53 (Prenote Credit) |
- | | | Reversals Only) | 58 (Prenote Debit) |
- +---------------------+-------------------+---------------------+-------------------------+
- Critical Transaction Code Rules
Loan Accounts (Code 57) : A debit transaction to a loan account ( 57 ) is strictly prohibited for regular payment origination . It is permitted solely for reversing an erroneous credit entry previously posted to the loan account.
Zero-Dollar Remittance (Codes 24, 34, 44) : Used in CCD and CTX corporate payments to transmit ANSI ASC X12 or payment-related information via addenda records when no monetary funds transfer occurs.
Prenotifications (Codes 23, 28, 33, 38, 43, 48, 53, 58) : Non-dollar entries used to validate account number and routing validity prior to initiating live transactions. The Amount field in Position 30–39 must be all zeros ( 0000000000 ).
- Trace Number Structure & Check Digit Modulus 10
- 1. Trace Number Composition (Positions 80–94)
Every Entry Detail record is assigned a globally unique 15-digit Trace Number by the ODFI: Trace Number = ODFI Routing Number (First 8 Digits) ⏟ Positions 80–87 + 7-Digit Ascending Sequence Number ⏟ Positions 88–94 \text{Trace Number} = \underbrace{\text{ODFI Routing Number (First 8 Digits)}}_{\text{Positions 80–87}} + \underbrace{\text{7-Digit Ascending Sequence Number}}_{\text{Positions 88–94}} Trace Number = Positions 80–87 ODFI Routing Number (First 8 Digits) + Positions 88–94 7-Digit Ascending Sequence Number
Example : If ODFI routing number is 121000358 and this is the 4th entry in the batch, the Trace Number is 121000350000004 .
Audit & Tracing : The Trace Number is referenced in all subsequent exception processing, including Returns ( Type 7, Addenda 99 ), Notifications of Change ( Type 7, Addenda 98 ), and trace inquiries.
2. Modulus 10 Check Digit Calculation (Position 12)
The 9th digit of an RDFI routing number (Position 12) validates the preceding 8 digits (Positions 04–11) using the Modulus 10 weighting algorithm (weights: 3, 7, 1, 3, 7, 1, 3, 7): Weighted Sum S = ( d 1 × 3 ) + ( d 2 × 7 ) + ( d 3 × 1 ) + ( d 4 × 3 ) + ( d 5 × 7 ) + ( d 6 × 1 ) + ( d 7 × 3 ) + ( d 8 × 7 ) \text{Weighted Sum } S = (d_1 \times 3) + (d_2 \times 7) + (d_3 \times 1) + (d_4 \times 3) + (d_5 \times 7) + (d_6 \times 1) + (d_7 \times 3) + (d_8 \times 7) Weighted Sum S = ( d 1 × 3 ) + ( d 2 × 7 ) + ( d 3 × 1 ) + ( d 4 × 3 ) + ( d 5 × 7 ) + ( d 6 × 1 ) + ( d 7 × 3 ) + ( d 8 × 7 ) Check Digit d 9 = ( 10 − ( S m o d 10 ) ) m o d 10 \text{Check Digit } d_9 = (10 - (S \bmod 10)) \bmod 10 Check Digit d 9 = ( 10 − ( S mod 10 )) mod 10
Worked Example: Check Digit Calculation
For routing number 07100001 : S = ( 0 × 3 ) + ( 7 × 7 ) + ( 1 × 1 ) + ( 0 × 3 ) + ( 0 × 7 ) + ( 0 × 1 ) + ( 0 × 3 ) + ( 1 × 7 ) S = (0 \times 3) + (7 \times 7) + (1 \times 1) + (0 \times 3) + (0 \times 7) + (0 \times 1) + (0 \times 3) + (1 \times 7) S = ( 0 × 3 ) + ( 7 × 7 ) + ( 1 × 1 ) + ( 0 × 3 ) + ( 0 × 7 ) + ( 0 × 1 ) + ( 0 × 3 ) + ( 1 × 7 ) S = 0 + 49 + 1 + 0 + 0 + 0 + 0 + 7 = 57 S = 0 + 49 + 1 + 0 + 0 + 0 + 0 + 7 = 57 S = 0 + 49 + 1 + 0 + 0 + 0 + 0 + 7 = 57 d 9 = ( 10 − ( 57 m o d 10 ) ) m o d 10 = ( 10 − 7 ) m o d 10 = 3 d_9 = (10 - (57 \bmod 10)) \bmod 10 = (10 - 7) \bmod 10 = 3 d 9 = ( 10 − ( 57 mod 10 )) mod 10 = ( 10 − 7 ) mod 10 = 3 Complete 9-Digit Routing Number = 071000013 \text{Complete 9-Digit Routing Number} = \mathbf{071000013} Complete 9-Digit Routing Number = 071000013
Addenda Record Architecture (Type 7)
When Position 79 of a Type 6 record is set to 1 , one or more Type 7 Addenda records immediately follow.
Field Positions Length Type Name Contents / Validation Rules
1 01–01 1 N Record Type Code Mandatory constant 7 . Identifies record as Addenda.
2 02–03 2 N Addenda Type Code Identifies addenda category: 05 (Payment Related), 98 (NOC), 99 (Return), 10 – 18 (IAT).
3 04–83 80 A/N Payment Related / Exception Information 80 characters of ANSI ASC X12 EDI text, return reason codes/original trace, or NOC change data.
4 84–87 4 N Addenda Sequence Number Sequential integer starting at 0001 for each addenda attached to this Type 6 entry.
5 88–94 7 N Entry Detail Sequence Number Must exactly match Positions 88–94 of the parent Type 6 Trace Number . Links addenda to entry.
Key Addenda Type Codes
05 (Payment Related Information) : Used with PPD , CCD , and WEB (single addenda) and CTX (up to 9,999 addenda) to convey invoice numbers, account descriptions, or ASC X12 820 payment orders.
98 (Notification of Change / NOC) : Generated by RDFIs using COR SEC code. Contains Change Code ( C01 – C13 ), original entry trace number, and corrected routing/account data.
99 (ACH Return Record) : Generated by RDFIs to return dishonored or unauthorized entries. Contains the 3-character Return Reason Code ( R01 – R99 ), Original Entry Trace Number, Date of Death (if applicable), and Original RDFI Routing Number.
10 through 18 (International ACH Transactions / IAT) : Mandatory sequence of 7 addenda records conveying foreign exchange data, Originator address, Beneficiary address, and correspondent bank identifiers for OFAC screening.