ATR Info Gemalto Classic TPC IS

		STUDY

The Gemalto Classic TPC IS (GemSafe Xpresso 32K) is our showcase for a detailled discussion of the parameters of an ATR. for demonstrating the ATR-Basics with a real life card. You find in the ATR column the hexadecimale values of the ATR-Bytes, the 0xhh notation means hexadecimale values.

This processor chip card contains two ATR’s. At first reset, the ATR 1 is transmitted to the card reader. If the reader can work with this parameters, the communication is continued. If not, a new reset is done for getting ATR 2, operating with slower parameters. For more details look at the ISO/IEC 7816-3.

The Classic TPC IS card is a T=0 card, using T=1 cards you have to consider more protocol specific parameter, see ATR-Infos der CardOS 4.3B carte of Siemens.

Gemalto SafesITe Xpresso R3.2 32k

ATR 1: 3b7d94000080318065b08301029083009000

ATR Bytes	their meaning
TS=0x3b (direct)	Direct Convention: Low = 0, High = 1; LSB transmitted first
T0=0x7d (Y(1)=7,K=13)	MSN: 0111, 1 means appearance of Interface Characters (TD(1) - TA(1)); LSN: number of Historical Bytes (13)
TA(1)=0x94 (FI=9,DI=4)	FI (Clock rate conversion factor): 9(1001) -> 512, f(max) = 5 MHz; DI (Baud rate adjustment factor): 4(0100) -> 8
TB(1)=0x00 (II=0,PI1=0)	II (Reference to max. programming current) 0(00) -> 25mA; PI (Programming Voltage) 0(00000) -> no voltage at Vpp
TC(1)=0x00 (N=0)	Referenzwert für die Berechnung einer zusätzlichen Guardtime (Zeit zwischen zwei Datenbytes bei der Übertragung)
T1=0x80	Historical Byte
T2=0x31 '1'	Historical Byte
T3=0x80	Historical Byte
T4=0x65 'e'	Historical Byte
T5=0xb0	Historical Byte
T6=0x83	Historical Byte
T7=0x01	Historical Byte
T8=0x02	Historical Byte
T9=0x90	Historical Byte
T10=0x83	Historical Byte
T11=0x00	Historical Byte
T12=0x90	Historical Byte
T13=0x00	Historical Byte
TCK is missed	no check byte

Parameter	Meaning
f(min)=1000kHz (default)	minimum frequency: 1MHz
f(max)=5000kHz	maximum frequency: 5MHz
Fi=512	Clock rate conversion factor
Di=8	Baud rate adjustment factor
N=0	Extra Guardtime
P=0dV	programming voltage
I=25mA	programming power
X=Not supported (default)	Clock stop indicator
U=A only (default)	Class indicator for operation (Class A = 5V, Class B = 3V)
WI=10 (default)	Factor for computing Work Waiting Time (time between two rising edges of following characters)
T(supp)=0	Protocol type: T=0

ATR 2: 3b6d000080318065b08301029083009000

ATR-Bytes	Meaning
TS=0x3b (direct)	Direct Convention: Low = 0, High = 1; LSB wird zuerst übertragen
T0=0x6d (Y(1)=6,K=13)	MSN: 0110, 1 means appearance of Interface Characters (TD(1) - TA(1)); LSN: number of Historical Bytes (13)
TB(1)=0x00 (II=0,PI1=0)	II (Reference to max. programming current) 0(00) -> 25mA; PI (Programming Voltage) 0(00000) -> no voltage on Vpp
TC(1)=0x00 (N=0)	Reference value for computing additional guardtime
T1=0x80	Historical Byte
T2=0x31 '1'	Historical Byte
T3=0x80	Historical Byte
T4=0x65 'e'	Historical Byte
T5=0xb0	Historical Byte
T6=0x83	Historical Byte
T7=0x01	Historical Byte
T8=0x02	Historical Byte
T9=0x90	Historical Byte
T10=0x83	Historical Byte
T11=0x00	Historical Byte
T12=0x90	Historical Byte
T13=0x00	Historical Byte
TCK is missed	no check byte

Parameter	Meaning
f(min)=1000kHz (default)	Minimum Frequency: 1MHz
f(max)=5000kHz	Maximum Frequency: 5MHz
Fi=372 (default)	Clock rate conversion factor (not indicated in ATR -> default value)
Di=1 (default)	Baud rate adjustment factor (not indicated in ATR -> default value)
N=0	Extra Guardtime
P=0dV	programming voltage
I=25mA	programming power
X=Not supported (default)	Clock stop Indicator
U=A only (default)	Class indicator for operation (class A = 5V, class B = 3V)
WI=10 (default)	Factor for computing the Work Waiting Time
T(supp)=0	protocol type: T=0

Meaning of the Parameter

As seen above, the single bytes of the ATR indicate certain values. The main difference of the two ATRs are the values of Fi and Di, which have the main responsibility of reached baud rates.

ATR 1: Fi: 512, Di: 8
ATR 2: Fi: 372, Di: 1

If the reader can work with parameters of ATR1, the performance of the reader is better, because transmittance of commands to the card can be done faster. If the reader can, because of its specifics, only operate with values of ATR 2 the performance values are significant worse.

Conclusion

The performance results of a card reader depends strongly on the used smart card. To compute the etu (elementary time unit), the time length for transmittance of one bit, you need the frequency and the conversion and the adjustment factor. The formula is

1 etu = (F/D) * (1/f)

F = Clock rate conversion factor
D= Baud rate adjustment factor
f = Frequency (Hz)

Concretely the Gemalto Classic TPC IS (GemSafeXpresso 32 k) card results - using ATR 1 - in an etu about ap.12 ms (Fi = 512, Di = 8, f = 5 MHz) Compare it to ATR 2, where an etu about ap. 74 ms (at Fi = 372, Di = 1, f = 5 MHz) is reached. For the user more interesting is the baudrate of the communication with the card. You can compute it with:

Baudrate = (f/F) * D

ATR 1 has a maximum baudrate of 78125; ATR 2 of 13440. These values are accepted by the card. Crucial is the frequency of the card reader - resulting in other baudrates. Due to this facts it is possible, that a card reader can communicate very fast with one card, while another card seems to be extremely slow. You can see this perception in your Reader Test.