What does RF Cal means? I'm using android samsung galaxy s5. When I entered in the dial *#12580*369# it appeared some information about the phone. One of them is RF Cal (it is formated like a date). 


Does anyone knows what it is? 
What does RF Cal stands for?
Where this terminology came from? What organization / person coined it?
If RF Cal is the manufacturing date of the phone, then why not just call it manufacturing date of MFD for example? is it because there is a difference?
RF Cal stands for "Radio Frequency Calibration". For smart phones, it means "time of first power up". After assembly, some parts of the phone(e.g. magnetometer &amp; proximity sensor, radio chips and antennae)  must be calibrated before it's correctly functional. It is slightly different from "manufacture time", because hardware calibration is after the device is fully assembled. You can simply think it's "time of the end of manufacture of this device".