The data frame format of IEEE 802.15.4 is one of the two most basic and important packet structures. The data payload maximum capacity is 102 Bytes at the MAC level. The full physical protocol data unit (PPDU) has a maxium of 133 Bytes or 1064 bits for a 4.256 ms transmission at 250 Kbps. The PPDU mininum is 16 Bytes or 128 bits for a 0.512 ms transmission at 250 Kbps. The data sequences are numbered to ensure that the packets are tracked, the robust structure improves receptions in difficult environments, and the frame check sequence, or FCS, validates error free data.