USB = Single Sideband reception mode UPPER SIDE BAND
LSB = Single Sideband reception mode LOWER SIDE BAND
USB/LSB are forms of 'SSB' communication. SSB provides extra-long range communication capabiliy, but sacrifices audio quality to do so. SSB also requires tuning a balanced modulator to re-insert the missing carrier to allow the audio information to be used. This is finicky and mis-tuning can result in reception of voice communication sounding like Donald Duck. Note: throughout North America, most HF
SSB transmissions are USB only, and many newer aircraft HF
radios only support USB.
= AMPLITUDE MODULATION (standard braodcast - both sidebands, carrier frequency not suppressed). AM
basically provides acceptable audio quality without extra clarification processes, but doesn't provide the extra-long range communication power associated with SSB.
DATA = I'm not completely certain here, but this will likely invoke filters which help block noise from interfering with reception of digital tramissions like RTTY (Radio TeleType) or FAX (weather maps)
= CONTINUOUS WAVE mixes a BFO (beat frequency oscillator) tone with the received signal to make morse code transmissions easier to decode (especially if they are unmodulated)