Track 2 can store up to 40 numeric or special characters; it uses a lower density magnetic encoding than Track 1 but a more compact character encoding. ISO 7813 specifies the following structure for track 2 data:[2]
Track 3 uses the same density as track 1 but has the same character encoding as track 2, allowing it to store 107 numeric characters.[2] It is virtually unused by the major worldwide networks and often isn't present on payment cards.[citation needed]
A notable exception to this is Germany, where Track 3 content was used nationally as the primary source of authorization and clearing information for debit card processing prior to the adoption of the "SECCOS" ICC standards. Track 3 is standardized nationally to contain both the cardholder's bank account number and branch sort code (BLZ).[citation needed]
