require four bits to encode fig5 it is possible to use the least significant bit of the characters r c r and c u2032 to encode the ecc level as shown the group error correction is determined by the user when generating a symbol and fixed for the one or more 48 byte data groups or portions thereof that make a symbol the 16 levels of group ecc may be represented by a 4 bit binary symbol e g 2 is 0010 10 is 1010 15 is 1111 etc where the descending bit positions b 3 b 2 b 1 b 0 fill the least significant bit of r c r c u2032 respectively in one embodiment you select a 48 byte data group you take the amount of data from the overall message fill those portions of the data groups that will fit within the one or more 48 byte data groups again in one embodiment from 4 to 34 bytes of overhead per 48 byte data group will be dedicated to error correction then generate those 4 to 34 bytes of ecc error check bytes which will be placed within the data group by calculating the systematic reed solomon encoding using the galois field the polynomial arithmetic for the reed solomon calculation is identical to that used in the data matrix ecc 200 calculations per.