The parity coverage for SpaceWire is a bit unusual, as it follows that of IEEE1355-1995. Because of the different lengths of control and data character, the parity field of the previous character includes the data/control flag of the next character. This is so that the length of the following character is validated by the parity bit before that character is decoded. This avoids incorrect decoding of a character when its data/control flag is in error.
Figure 33 Data and Control Characters Parity Coverage