IEEE Standard for Low-Frequency (less than 500 kHz) Narrowband Power Line Communications for Smart Grid Applications - Amendment 1

Changes to clarify how and when to encrypt header and payload information elements, update the interleaver design in order to eliminate some drawbacks in certain channels, a new PHY data primitive attribute so sub-band SNR data can be obtained from the PHY, modification to the frame counter size for security to make it consistent with IEEE Std 802.15.4e(TM)-2012, and adding a beacon attribute and change the zero crossing detector text are addressed in this amendment.