Numbers from bit 1 to bit 12 are represented by the following variables: x4, x3, x2, x 1, y, z7, z6, z5, Z4, z3, z2, z 1.
The calculation formula of parity bit is:
(X4 * 2+X3 * 3+X2 * 4+x 1 * 5+Y * 6+Z7 * 7+Z6 * 8+Z5 * 9+Z4 * 2+Z3 * 3+Z2 * 4+z 1 * 5)MOD( 1 1)
If the remainder is a few, the parity bit is a few. If the remainder is 10, the corresponding parity bit is X. ..
take for example
2007 10308494.X
(2 * 2+0 * 3+0 * 4+7 * 5+ 1 * 6+0 * 7+3 * 8+0 * 9+8 * 2+4 * 3+9 * 4+4 * 5)mod( 165438+。