ISO/IEC 7811 Identification Cards

Most magnetic cards, including financial transaction cards, conform to the ISO/IEC 7811 standard, which defines the location of the magnetic stripe, as well as the data layout of each track in the magnetic stripe. Each of the three tracks are available for data input.

Track 1

Track 1, developed by the International Air Transport Association (IATA), is encoded at a recording density of 210 bits per inch. It contains up to 79 alphanumeric characters, including the primary account number, name of the account holder, expiration date, and/or 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 the % character
Format Code	Alphabetic character describing the format of the track
Primary Account Number	Maximum of 19 characters; typically matches the card number printed on the front of the card
Field Separator	One character in length; typically the ^ character
Name	Maximum of 26 alphanumeric characters
Field Separator
Additional Data	Typically contains the expiration date (4 characters YYMM) and/or the service code (3 characters)
Discretionary Data	Typically 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 the ? character
Longitudinal Redundancy Check (LRC)	One character in length, calculated from the other data on the track; used to verify the contents of the information contained in the track

Track 2

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

; : < = > . ?

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

Data	Description
Start Sentinel	One character in length; typically the ; character
Primary Account Number	Maximum of 19 characters; typically matches the card number printed on the front of the card
Field Separator	One character in length; typically the = character
Additional Data	Typically contains the expiration date (4 characters YYMM) and/or the service code (3 characters)
Discretionary Data	Typically 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 the ? character
Longitudinal Redundancy Check (LRC)	One character in length, calculated from the other data on the track; used to verify the contents of the information contained in the track

Track 3

Track 3, developed by the Thrift Industry, is used less often than tracks 1 or 2. It reads numeric data at 210 bits per inch. It contains up to 104 numeric characters, including the primary account number, security data, and/or additional account information. In addition to numeric characters, track 3 also accepts the following six characters:

; : < = > . ?

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

Data	Description
Start Sentinel	One character in length; typically the ; character
Format Code	Two digits describing the format of the track
Primary Account Number	Maximum of 19 characters; typically matches the card number printed on the front of the card
Field Separator	One character in length; typically the = 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 the ? character
Longitudinal Redundancy Check (LRC)	One character in length, calculated from the other data on the track; used to verify the contents of the information contained in the track