Article from the series "ATR statistics".
TC4TC4 should have the same meaning as TC3.
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 none of them defines an TC4.