TC3The ISO 7816-3 specification is not public. So I can't copy/paste part of the text. I will use Wikipedia instead.
For T = 1: type of error detection code used
Bit 1 of the first TC for T=1 indicates the error detection code to be used:
- CRC if bit 1 is set to 1;
- LRC (default value) if bit 1 is set to 0.
In my list of ATR the only redundancy code used if LRC. I found no card using CRC.
LRC is the default algorithm. But 55 cards explicitly set it. I have no explanation for that.