With respect to the last post, the Air Data Computer (ADC) receives IAS from the raw Pitot and Static information, and then removes position errors to deliver CAS (or RAS if you call it that) to the PFD.
To avert the possibility of ADC error, "raw" IAS is supplied to the standby IAS, thus the standby ASI reads IAS.
In the calibration process (as opposed to the removal of position error), the effects of compressibility according to ISA / Sea Level conditions are removed, thus, except at ISA / Sea Level, the PFD airspeed display does NOT read EAS, but CAS with all of the attendant compressibility errors.
Regards,
Old Smokey