It's not in reference to a transponder setting, but is issued in a departure clearance with the transponder setting.
"Standard Noise" means the aircraft is to depart the airfield using the "standard noise" abatement procedure, which is designed to avoid upsetting the local residents by excessive noise, or routing over particularly noise-sensitive areas. It defines where to turn, what climb rate is to be used, etc. etc. They are found (for each airport) in the Jeppesen/Aerad/Whatever plates for the field.