ISO/IEC 4909:2006

Overview

ISO/IEC 4909:2006 specifies the magnetic stripe data content for track 3 on financial transaction cards. The standard defines the sequence, length and encoding of data fields stored on track 3 to permit international interchange of magnetic-stripe card information. It is intended to be used together with physical and recording specifications from ISO/IEC 7810, ISO/IEC 7811 and issuer identification rules in ISO/IEC 7812.

Key topics and technical requirements

• Track formats: Two format codes (01 and 02) with defined field layouts for track 3.
• Data fields: Standardized fields include start/end sentinels, format code, Primary Account Number (PAN), country code, currency (ISO 4217 codes), currency exponent, amounts, cycle information, expiry date, card sequence number, card security number, crypto check digits (CCD) and additional data (e.g., transaction date, verification values).
• Field types: Fields are classified as Mandatory/Optional, Static (issuer-written) or Dynamic (updated by interchange partners). Dynamic fields must be rewritten on update.
• Encoding: Uses the 5‑bit numeric character set as defined in ISO/IEC 7811; maximum of 107 characters on track 3.
• Physical/location rules: Track 3 read/write locations and magnetic material performance conform to ISO/IEC 7811 parts; card physical characteristics follow ISO/IEC 7810.
• Interchange modes: Track 3 can be used in conjunction with track 2 (read both, update track 3 if required) or independently (read/write only track 3) depending on mutual agreement between parties.
• Integrity and checks: Includes longitudinal redundancy check (LRC) and use of check digits where applicable.

Applications and who uses ISO/IEC 4909:2006

• Card issuers and personalization bureaus - to format and write track 3 data consistently for cards that support read/write magnetic stripes.
• Payment networks, acquirers and issuers - to enable interoperable on-line and off-line transaction processing using track 3 data.
• Terminal and ATM manufacturers - to implement readers/writers that handle track 3 encoding, dynamic updates and LRC checks.
• Security and compliance teams - to understand what sensitive fields may be present (PAN, CCD, PINPARM) and how they are maintained or updated.
• Integrators and system architects - when designing interchange flows that require track 3 use in conjunction with track 2 or as an alternative.

Related standards

• ISO/IEC 7810 - Identification cards (physical characteristics)
• ISO/IEC 7811 (all parts) - Recording technique and magnetic stripe encoding
• ISO/IEC 7812 (all parts) - Issuer identification and PAN structure
• ISO 4217 - Currency codes
• ISO 9564-2 - PIN encipherment algorithms

ISO/IEC 4909:2006 is essential for ensuring magnetic stripe interoperability, correct track 3 data encoding, and reliable international financial card interchange.