As previously discussed, the ATmega128RFA1 offers high data rates up to 2Mbit/s. When designing wireless systems it pays to keep in mind that the effective data rate is smaller than the selected data rate due to the overhead caused by various control signals and checksum computations as defined by the IEEE 802.15.4 standard. The overhead depends further on the length of the Physical layer Service Data Unit (PSDU). Generally the High Data Rate modes offer a higher effective data rate while occupying the same RF channel bandwidth as the IEEE 802.15.4 2.4GHz 250kb/s standard mode. High Data Rate transmission and reception is useful for large PSDU lengths due to the higher effective data rate, further reducing the power consumption of the system.