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Custom Legacy or SAP-to-SAP Integrations

Introduction: The Reality of Integration in Evolved Landscapes

Modern enterprises rarely run on a single monolithic system. Instead, they carry decades of legacy—from proprietary attendance systems to mainframe payroll sub-engines, and custom-built SAP add-ons tailored for industry-specific processes.

Many organizations running SAP ECC or S/4HANA today still depend on:

1

In-house time tracking systems (built in C++ or Oracle) 

2

Old ABAP reports generating GL entries

3

External finance systems outside of SAP

4

Custom benefits logic built pre-SuccessFactors era

The challenge? These systems weren’t designed to talk to SAP. But now, they must.
And when SAP-to-SAP or SAP-to-legacy integration is required—with minimal middleware, full control, and compliance—point-to-point becomes the smartest approach.

Use Case Categories for Custom P2P Integrations

Category

SAP-to-SAP
Legacy System Integration
Flat File Feeds
Internal Application Sync
Historical Data Ingestion

Examples

ECC HR ↔ ECC Finance, SAP HCM ↔ SAP CATS, SAP PS ↔ SAP Payroll
Oracle Time Clock, COBOL-based HRMS, FoxPro payrolls
Excel → SAP Master Data, CSV → Infotype 2006 Absence Quota
In-house React portals ↔ SAP NetWeaver services
Legacy HR records migration via custom loaders

High-Level Integration Architecture

 Real-Time Verification Requests

SAP-to-SAP (Tightly Coupled Systems)

SAP-to-Legacy (Loosely Coupled Systems)

  • Uses RFCs (CALL FUNCTION... DESTINATION)
  • IDocs where message granularity is needed
  • Custom ABAP report + file generation
  • Scheduled jobs (SM36) for periodic processing
  • Flat file ingestion (CSV, XML, JSON)
  • ABAP parser + transformation logic
  • Intermediate Z-tables in SAP
  • Scheduled jobs (SM36) for periodic processing
  • Optionally: external connectors (e.g., SAP JCo, Python API wrappers)

Real Integration Examples

Legacy Time System ↔ SAP Payroll

External clock system exported punch.csv nightly 
ABAP job imported punches, validated IN/OUT logic 
Wage types derived via ZT00 schema and posted to Infotype 2010 

BIB Configuration in ECC

BC Sets define mappings between EC fields and Infotype structures
Transformation templates apply conditional logic (e.g., map ‘FULLTIME’ → IT0007 Schedule)
Switch framework manages client-specific variations

Middleware (SAP CPI / Boomi)

Routes API responses to SAP ECC
Applies minimal transformations (field renaming, timestamping)
Forwards to BIB-enabled ECC system

Custom ABAP Parser & Validator

Parses incoming data files:

  • Validates employee ID, timestamps, wage types
  • Flags duplicates or structural mismatches
  • Writes to Z-log or raises error workflow

Error Logging & Exception Tracing

  • Use SLG1 or custom ZLOG tables
  • Email workflows triggered on file parse failures
  • Job-level logs (SM37 monitoring)
  • API call simulation and timeout handling

Testing Strategy

Layer

File
API
RFC
DB
ABAP Logs

Security Approach

SFTP with private key exchange
OAuth/SAML, user-specific tokens
Trusted connection with limited dialog user
No direct connection preferred—use staging files
SLG1 + Role-based viewing (P_ABAPLOG)

Always enforce: 

  • Secure directory paths
  • Transaction code restrictions (SM69, SM49)
  • Logging of ALL file reads and writes

Data Format Compatibility Matrix

Source System

Legacy Time
Old HRMS
SAP ECC FIFSA_PRETAX
External HR Portal
Oracle DB

Format

CSV 
Excel 
RFC 
JSON 
Flat File / DB View 

Format Integration Method

File → Infotype 2011 
Excel → Z-table → Infotypes 
Z report → BAPI_ACC_DOCUMENT_POST 
RESTful → SAP Gateway 
Shared staging → SAP Job 

ABAP Tool

Z Parser 
ALSM_EXCEL_TO_INTERNAL_TABLE 
Remote-enabled FM 
JSON Handler Class 
JDBC or File Ingestion 

Payroll Integrations – The Heart of SAP Precision

Payroll is the single most critical and risk-sensitive area in any SAP deployment. Integrating third-party systems into your payroll processes—without losing control of retroactivity, wage type generation, and deduction accuracy—requires a level of precision that only SAP-native point-to-point integrations can offer. 

  • In Transit: When data is transferred between servers or to end-users, it is encrypted using secure communication protocols such as Transport Layer Security (TLS) or Secure Socket Layer (SSL). This ensures that data remains protected from interception or eavesdropping during transmission over the internet.
  • At Rest: Cloud providers use advanced encryption algorithms to encrypt data before storing it in their storage systems. Each piece of data is encrypted with a unique encryption key, which is securely managed by the cloud provider.

In this tab, we explore real-world SAP payroll integrations with:
Fidelity (401(k), Roth, Catch-Up)
Equifax (W-2 delivery, income/employment verification)

We dive into Infotype structures, ABAP interface designs, compliance considerations, and how to build integrations aligned with your payroll control record lifecycle. 

What Is Point-to-Point Integration?

At its core, point-to-point integration is the direct, tightly coupled connection between SAP and a third-party system, bypassing generic middleware tools. This method:

1. Reduces latency

2. Improves customization

3. Simplifies error handling

4. Aligns closely with payroll and compliance needs

Rather than sending data into a black box middleware, you're in full control—writing ABAP logic that knows exactly which Info type, PA subtype, or Wage Type to manipulate.

Outbound (SAP → Third Party) 

1. Data Extraction: Use ABAP programs or LSMW tools to pull employee master data, time punches, deduction records, etc. Accessed from Infotypes like 0002, 0167, 0378, 2010, 2011

2. Transformation: ABAP logic maps SAP internal formats to the vendor’s schema (e.g., Fidelity fixed-width layout, Alight’s ANSI X12)

3. File Generation & Encryption: Generated file stored on the SAP application server or NFS path PGP encryption applied if needed

4. Secure Transmission: Transferred via SFTP using command-line tools or SAP’s own connectivity add-ons

5. Audit Logging: All activity logged via custom Z-tables or application logs (SLG1)

Real-Life Implementation Highlights

Metric

Manual HR imports
Data inconsistency incidents
Onboarding time 
Payroll errors due to mismatches 
Maintenance effort 

Before BIB

Weekly
Frequent
2–3 days
8%
High

After BIB

None
Rare
Same day 
<1% 
Low (config-driven) 

Sample Input File from Kronos

Testing Approach

Test Type

Interface Simulation
Field Mapping Validation
Error Handling
Performance
Manual Override Test

Objective

Verify parser handles edge data
Ensure correct translation into Infotype fields
Corrupt file, invalid data
Handle high-volume legacy data dumps
Reprocessing failed entries without duplication

Business Benefits

Metric

Pre-Integration

Post-Integration


Manual time file entry

3 hours/day
Payroll mismatch cases

60+/month
HR data duplication 

Frequent

Near-zero
Audit trail quality

Weak

Strong and searchable
Exception visibility

Poor
Logged, emailed, and trackable 

How Mapping Works in BIB

  • Field Mapping Tables (V_T77SFEC_BIBF): Defines EC → Infotype field relationships
  • Transformation Templates: Handle conversion logic (e.g., map EC ‘grade’ to SAP ‘job group’)
  • Filters: Set by country, employment type, event reason
  • Switches: To allow client-specific logic branching
  • In Transit: When data is transferred between servers or to end-users, it is encrypted using secure communication protocols such as Transport Layer Security (TLS) or Secure Socket Layer (SSL). This ensures that data remains protected from interception or eavesdropping during transmission over the internet.
  • At Rest: Cloud providers use advanced encryption algorithms to encrypt data before storing it in their storage systems. Each piece of data is encrypted with a unique encryption key, which is securely managed by the cloud provider.

How Mapping Works in BIB

1. Data Extraction: Use ABAP programs or LSMW tools to pull employee master data, time punches, deduction records, etc. Accessed from Infotypes like 0002, 0167, 0378, 2010, 2011

2. TransformField Mapping Tables (V_T77SFEC_BIBF): Defines EC → Infotype field relationships 
Transformation Templates: Handle conversion logic (e.g., map EC ‘grade’ to SAP ‘job group’) 
Filters: Set by country, employment type, event reason 
Switches: To allow client-specific logic branching ation: ABAP logic maps SAP internal formats to the vendor’s schema (e.g., Fidelity fixed-width layout, Alight’s ANSI X12)

 3. File Generation & Encryption: Generated file stored on the SAP application server or NFS path PGP encryption applied if needed

4. Secure Transmission: Transferred via SFTP using command-line tools or SAP’s own connectivity add-ons

5. Audit Logging: All activity logged via custom Z-tables or application logs (SLG1)

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