Casio QT-6600 Reference Manual page 88

Application System
Magenetic card specification
R-88
Track-1, Format B:
Start sentinel - one character (generally '%')
Format code = "B" - one character (alpha only)
Primary account number (PAN) - up to 19 characters
Field separator - one character (generally '~')
Name - two to 26 characters
Field separator - one character (generally '~')
Expiration date - four characters in the form MMYY
Service code - three characters
Discretinary data - may include Pin Verification Key Indicator (PVKI, 1 character),
Pin Verification Value (PVV, 4 characters)
Card Verification Value or Card Verification Code (CVV or CVK, 3
characters)
End sentinel - one character (generally '?')
Longitudinal redundancy check (LRC) - one character
Track-2:
Start sentinel - one character (generally ':')
Track number - 1, 2, 3
Primary Account Number (PAN) - up to 19 characters
Separator - one character (generally '=')
Expiration date - four characters in the form MMYY
Service code - three characters
Discretionary data - as in track one
End sentinel - one character (generally '?')
LRC - one character
Usually, but not always, matches the credit card number
printed on the front of the card.
Usually, but not always, matches the credit card number
printed on the front of the card