The radios can automatically adjust their mode of operation based on the atmospheric conditions. A radio's adaptive coding and modulation (ACM) function use its highest modulation (256 QAM) in ideal conditions to attain the highest bandwidth possible and automatically brings down the level of modulation (and therefore bandwidth over the air) as needed in inferior atmospheric conditions.
The collected ACM statistics include 15-min. and 24-hr statistics of the time spent at each QAM level for a radio. The statistics are collected in units of milliseconds.