Lesson 1DE32 Acquiring Institution Identification Code: format (LLVAR up to 11n), use in routing an acquiring identificationDescribes DE32 LLVAR numeric format an how acquirer identifiers assigned. Explains routin to di correct acquirer host, multi-acquirer setups, an how DE32 interacts wid network-specific routin tables.
LLVAR format and numeric constraintsAcquirer ID assignment and governanceUse of DE32 in network routingMulti-acquirer and aggregator modelsLogging DE32 for settlement mappingLesson 2DE41 Card Acceptor Terminal Identification: format (8an), terminal routing an loggingExplains DE41 format, uniqueness rules, an how terminals identified across merchants an locations. Covers routin, monitorin, fraud analysis, an how terminal IDs interact wid merchant an store hierarchies.
8an format and allowed charactersTerminal ID uniqueness strategiesTerminal ID in routing and profilesTerminal ID in fraud and risk rulesTerminal inventory and lifecycle useLesson 3DE2 Primary Account Number (PAN): field name, format (LLVAR up to 19 numeric), an role in routing/BIN lookupDetails DE2 structure, PAN length rules, an LLVAR encodin. Explains BIN ranges, routin decisions, an how PAN drives scheme, product, an issuer identification while respectin maskin an PCI constraints in logs.
LLVAR encoding and PAN length limitsBIN ranges and issuer identificationPAN role in network routing decisionsPAN validation and Luhn check usageMasking PAN in logs and PCI impactsLesson 4DE38 Authorization Identification Response: format (6an), issuing bank authorization code an audit useExplains DE38 structure, allowed characters, an how issuers generate authorization codes. Covers use in host logs, acquirer records, an dispute workflows, plus consistency rules between request an response messages.
Format 6an and character constraintsIssuer code generation strategiesMapping DE38 across request/responseUse in acquirer and issuer audit logsRole in chargeback and dispute researchLesson 5DE3 Processing Code: format (6n), meaning segments (transaction type, account type), an role in transaction routingExplains DE3 structure, includin transaction type, from an to account codes. Shows how processin code drives routin, fee logic, an authorization rules fi purchase, cash, reversal, an adjustment flows.
6n layout and segment meaningsCommon purchase and cash codesAccount selection and subaccount useRouting and fee rule determinationReversal and adjustment processingLesson 6DE39 Response Code: format (2an), interpretation rules an common response valuesExplains DE39 format, common response values, an mappin to business outcomes. Covers issuer an network responsibilities, decline versus referral handlin, an how acquirers interpret ambiguous codes.
2an format and value rangesCommon approval and decline codesSoft declines and retry guidanceIssuer versus network generated codesMapping codes to merchant messagesLesson 7DE37 Retrieval Reference Number: format (12an), role in reconciliation, disputes, an trackingDescribes DE37 format, generation logic, an uniqueness across time an systems. Explains how RRN supports reconciliation, dispute research, an cross-network trackin of related transactions.
12an format and structure optionsRRN generation and uniquenessUse in reconciliation processesRole in chargebacks and disputesCross-network transaction trackingLesson 8DE14 Expiration Date: format (YYMM), card validation an decline triggersCovers DE14 format, validation rules, an issuer checks at authorization time. Explains how expiry interacts wid card status, fallback, an how networks an acquirers handle near-expiry cards.
YYMM format and parsing rulesIssuer validation of expiry dateExpired card decline scenariosNear-expiry and renewal handlingStorage and masking in host logsLesson 9DE4 Amount, Transaction: format (12n), currency handling, an settlement implicationsDescribes DE4 format, scalin to minor units, an currency alignment wid DE49. Explains how authorization amounts affect holds, partial approvals, tips, an later clearin an settlement differences.
12n format and minor unit handlingCurrency consistency with DE49Preauthorization and hold amountsPartial approvals and tip handlingImpact on clearing and settlementLesson 10DE22 Point-of-Service Entry Mode: format (3n), values fi card-present, chip, contactless, keyedCovers DE22 format an codin fi magstripe, chip, contactless, an manual entry. Explains how entry mode affects risk scorin, fallback handlin, liability, an issuer authorization strategies fi different channels.
3n structure and subfield meaningsCard-present versus card-not-presentChip, contactless, and fallback codingManual and key-entered transaction flagsImpact on risk, fraud, and liabilityLesson 11DE7 Transmission Date & Time: format (MMDDhhmmss), role in logging, timeouts, an reconciliationDetails DE7 format, time zone considerations, an synchronization wid host clocks. Explains it role in timeout handlin, duplicate detection, reconciliation, an matchin authorizations wid clearin records.
MMDDhhmmss format and examplesTime zone and clock sync issuesUse in timeout and retry handlingDuplicate and late message detectionReconciliation and settlement matchingLesson 12DE49 Transaction Currency Code: format (3n, numeric ISO 4217), currency conversion an routing impactsCovers DE49 numeric ISO 4217 codin, relationship to DE4 an DE51, an how currency codes influence routin, FX conversion, an multi-currency merchant setups in authorization flows.
3n ISO 4217 numeric codesAlignment with DE4 and DE51Multi-currency merchant scenariosFX conversion and DCC decisionsRouting based on currency fieldsLesson 13DE11 System Trace Audit Number (STAN): format (6n), uniqueness, correlation between request/responseCovers DE11 numeric format, generation rules, an uniqueness windows. Explains how STAN links requests an responses, supports traceability across systems, an interacts wid RRN an internal audit keys.
6n format and rollover behaviorSTAN generation at switch or hostUniqueness windows and collisionsCorrelation of request and responseUse in monitoring and incident traces
