ISO/IEC 7811 Identification Cards

Track 1 was developed by the International Air Transport Association (IATA) and is encoded at a recording density of 210 bits per inch. It contains up to 79 alphanumeric characters, including the primary account number, the name of the account holder, the expiration date, and/or the account verification codes.

According to ISO specifications, the data format for track 1 is as follows.

Data	Description
Start Sentinel	One character in length; typically, this is the percent (%) character
Format Code	Alphabetic character that describes the format of the track
Primary Account Number	Maximum of 19 characters; typically, this matches the card number that is printed on the front of the card
Field Separator	One character in length; typically, this is the caret (^) character
Name	Maximum of 26 alphanumeric characters
Field Separator
Additional Data	Typically, this contains the expiration date (four characters in YYMM format) and/or the service code (three characters)
Discretionary Data	Typically, this contains the PIN Verification Key Indicator (PVKI), the PIN Verification Value (PVV), the Card Verification Value (CVV), and/or the Card Validation Code (CVC)
End Sentinel	One character in length; typically, this is the question mark (?) character
Longitudinal Redundancy Check (LRC)	One character in length, calculated from the other data on the track; this is used to verify the contents of the information that is contained in the track

Track 2 was developed by the American Bankers Association (ABA) for online financial transactions and is encoded at a recording density of 75 bits per inch. It contains up to 37 numeric characters, including the primary account number, the expiration date, and/or the account verification codes.

Track 2 also accepts the following characters:

• Semicolon (;)

• Colon (:)

• Left angle bracket (<)

• Equal sign (=)

• Right angle bracket (>)

• Period (.)

• Question mark (?)

According to ISO specifications, the data format for track 2 is as follows.

Data	Description
Start Sentinel	One character in length; typically, this is the semicolon (;) character
Primary Account Number	Maximum of 19 characters; typically, this matches the card number that is printed on the front of the card
Field Separator	One character in length; typically, this is the equal sign (=) character
Additional Data	Typically, this contains the expiration date (four characters in YYMM format) and/or the service code (three characters)
Discretionary Data	Typically, this contains the PIN Verification Key Indicator (PVKI), the PIN Verification Value (PVV), the Card Verification Value (CVV), and/or the Card Validation Code (CVC)
End Sentinel	One character in length; typically, this is the question mark (?) character
Longitudinal Redundancy Check (LRC)	One character in length, calculated from the other data on the track; this is used to verify the contents of the information that is contained in the track

Track 3 is used less often than tracks 1 or 2. It was developed by the thrift industry and is encoded at a recording density of 210 bits per inch. It contains up to 104 numeric characters, including the primary account number, the security data, and/or additional account information.

Track 3 also accepts the following characters:

• Semicolon (;)

• Colon (:)

• Left angle bracket (<)

• Equal sign (=)

• Right angle bracket (>)

• Period (.)

• Question mark (?)

According to ISO specifications, the data format for track 3 is as follows.

Data	Description
Start Sentinel	One character in length; typically, this is the semicolon (;) character
Format Code	Two digits that describe the format of the track
Primary Account Number	Maximum of 19 characters; typically, this matches the card number that is printed on the front of the card
Field Separator	One character in length; typically, this is the equal sign (=) character
Use and Security Data	Includes the Country Code (optional), Currency Code, Currency Exponent, Amount Authorized per Cycle, Amount Remaining this Cycle, Cycle Begin (Validity Date), Cycle Length, Retry Count, PIN Control Parameters (optional), Interchange Controls, PAN Service Restriction, SAN-1 Service Restriction, SAN-2 Service Restriction, Expiration Date (optional), Card Sequence Number, and/or Card Security Number (optional)
Additional Data	Includes the First Subsidiary Account Number (optional), Secondary Subsidiary Account Number (optional), Relay Marker, Cryptographic Check Digits (optional), and/or Discretionary Data
End Sentinel	One character in length; typically, this is the question mark (?) character
Longitudinal Redundancy Check (LRC)	One character in length, calculated from the other data on the track; this is used to verify the contents of the information that is contained in the track