5 Electronic signals and transmission protocols

11.113GPPRelease 1999Specification of the Subscriber Identity Module - Mobile Equipment (SIM-ME) InterfaceTS

Electronic signals and transmission protocols shall be in accordance with ISO/IEC 7816‑3 [26] unless specified otherwise. The following additional requirements shall be applied to ensure proper operation in the GSM environment.

The choice of the transmission protocol(s), to be used to communicate between the SIM and the ME, shall at least include that specified and denoted by T=0 in ISO/IEC 7816‑3 [26].

The values given in the tables hereafter are derived from ISO/IEC 7816‑3 [26] with the following considerations:

‑ VOH and VOL always refer to the device (ME or SIM) which is driving the interface. VIH and VIL always refer to the device (ME or SIM) which is operating as a receiver on the interface.

‑ this convention is different to the one used in ISO/IEC 7816‑3 [26], which specifically defines an ICC for which its current conventions apply. The following clauses define the specific core requirements for the SIM, which provide also the basis for Type Approval. For each state (VOH, VIH, VIL and VOL) a positive current is defined as flowing out of the entity (ME or SIM) in that state.

5.1 Supply voltage Vcc (contact C1)

The SIM shall be operated within the following limits.

Table 1: Electrical characteristics of Vcc under normal operating conditions

Symbol

Minimum

Maximum

Unit

Vcc

4,5

5,5

V

Icc

10

mA

The current consumption of the SIM shall not exceed the value given in table 1 during any state (including activation and deactivation as defined in subclause 4.3.2).

When the SIM is in idle state (see below) the current consumption of the card shall not exceed 200 µA at 1 MHz and 25°C. If clock stop mode is allowed, then the current consumption shall also not exceed 200 µA while the clock is stopped.

The ME shall source the maximum current requirements defined above. It shall also be able to counteract spikes in the current consumption of the card up to a maximum charge of 40 nAs with no more than 400 ns duration and an amplitude of at most 200 mA, ensuring that the supply voltage stays in the specified range.

NOTE: A possible solution would be to place a capacitor (e.g. 100 nF, ceramic) as close as possible to the contacting elements.

5.2 Reset (RST) (contact C2)

The ME shall operate the SIM within the following limits.

Table 2: Electrical characteristics of RST under normal operating conditions

Symbol

Conditions

Minimum

Maximum

VOH

IOHmax = +20 µA

Vcc‑0,7

Vcc (note)

VOL

IOLmax = ‑200 µA

0V (note)

0,6 V

tR tF

Cout = Cin = 30 pF

400 µs

NOTE: To allow for overshoot the voltage on RST shall remain between ‑0,3 V and Vcc+0,3 V during dynamic operation.

5.3 Programming voltage Vpp (contact C6)

SIMs shall not require any programming voltage on Vpp. The ME need not provide contact C6. If the ME provides contact C6, then, in the case of the ID‑1 SIM the same voltage shall be supplied on Vpp as on Vcc, while in the case of Plug‑in SIMs the ME need not provide any voltage on C6. Contact C6 may be connected to Vcc in any ME but shall not be connected to ground.

5.4 Clock CLK (contact C3)

The SIM shall support 1 MHz to 5 MHz. The clock shall be supplied by the ME. No "internal clock" SIMs shall be used.

If a frequency of 13/4 MHz is needed by the SIM to run the authentication procedure in the allotted time (see TS 03.20 [11]), or to process an ENVELOPE command used for SIM Data Download, bit 2 of byte 1 in the file characteristics shall be set to 1. Otherwise a minimum frequency of 13/8 MHz may be used.

The duty cycle shall be between 40 % and 60 % of the period during stable operation.

The ME shall operate the SIM within the following limits:

Table 3: Electrical characteristics of CLK under normal operating conditions

Symbol

Conditions

Minimum

Maximum

VOH

IOHmax = +20 µA

0,7xVcc

Vcc (note)

VOL

IOLmax = ‑200 µA

0 V (note)

0,5 V

tR tF

Cout = Cin = 30 pF

9 % of period with a maximum of 0,5 µs

NOTE: To allow for overshoot the voltage on CLK shall remain between ‑0,3 V and Vcc+0,3 V during dynamic operation.

5.5 I/O (contact C7)

Table 4 defines the electrical characteristics of the I/O (contact C7). The values given in the table have the effect of defining the values of the pull‑up resistor in the ME and the impedances of the drivers and receivers in the ME and SIM.

Table 4: Electrical characteristics of I/O under normal operating conditions

Symbol

Conditions

Minimum

Maximum

VIH

IIHmax = ± 20 µA (note 2)

0,7xVcc

Vcc+0,3 V

VIL

IILmax = +1 mA

‑0,3 V

0,8 V

VOH (note 1)

IOHmax = + 20µA

3,8 V

Vcc (note 3)

VOL

IOLmax = ‑1 mA

0 V (note 3)

0,4 V

tR tF

Cout = Cin = 30 pF

1 µs

NOTE 1: It is assumed that a pull‑up resistor is used in the interface device (recommended value: 20 kohms).

NOTE 2: During static conditions (idle state) only the positive value can apply. Under dynamic operating conditions (transmission) short term voltage spikes on the I/O line may cause a current reversal.

NOTE 3: To allow for overshoot the voltage on I/O shall remain between ‑0,3 V and Vcc+0,3 V during dynamic operation.

5.6 States

There are two states for the SIM while the power supply is on:

‑ the SIM is in operating state when it executes a command. This state also includes transmission from and to the ME;

‑ the SIM is in idle state at any other time. It shall retain all pertinent data during this state.

The SIM may support a clock stop mode. The clock shall only be switched off subject to the conditions specified in the file characteristics (see clause 9).

Clock stop mode. An ME of Phase 2 or later shall wait at least 1 860 clock cycles after having received the last character, including the guard time (2 etu), of the response before it switches off the clock (if it is allowed to do so). It shall wait at least 744 clock cycles before it sends the first command after having started the clock.

To achieve phase compatibility, the following procedure shall be adhered to:

– a SIM of Phase 2 or later shall always send the status information "normal ending of the command" after the successful interpretation of the command SLEEP received from a Phase 1 ME. An ME of Phase 2 or later shall not send a SLEEP command;

– a Phase 1 ME shall wait at least 744 clock cycles after having received the compulsory acknowledgement SW1 SW2 of the SLEEP command before it switches off the clock (if it is allowed to do so). It shall wait at least 744 clock cycles before it sends the first command after having started the clock.

5.7 Baudrate

The initial baudrate (during ATR) shall be: (clock frequency)/372. Subsequent baudrate shall be: (clock frequency)/372 unless the PPS procedure has been successfully performed. In that case the negotiated baudrate shall be applied according to subclause 5.8.2.

5.8 Answer To Reset (ATR)

The ATR is information presented by the SIM to the ME at the beginning of the card session and gives operational requirements.

5.8.1 Structure and contents

The following table gives an explanation of the characters specified in ISO/IEC 7816‑3 [26] and the requirements for their use in GSM. The answer to reset consists of at most 33 characters. The ME shall be able to receive interface characters for transmission protocols other than T=0, historical characters and a check byte, even if only T=0 is used by the ME.

Table 5: ATR

Character

Contents

sent by

the card

a) evaluation by the ME

b) reaction by the ME

1. Initial character

TS

coding convention for all subsequent characters (direct or inverse convention)

always

a) always

b) using appropriate convention

2. Format
character

T0

subsequent interface characters, number of historical characters

always

a) always

b) identifying the subsequent
characters accordingly

3. Interface
character
(global)

TA1

parameters to calculate the work etu

optional

a) always if present

b) if TA1 is not ’11’ or ’01’, PPS procedure
shall be used (see subclause 5.8.2)

4. Interface
character
(global)

TB1

parameters to calculate the programming voltage and current

optional

a) always if present

b) if PI1 is not 0, then reject the SIM (in accordance with subclause 5.10)

5. Interface
character
(global)

TC1

parameters to calculate the extra guardtime requested by the card; no extra guardtime is used to send characters from the card to the ME

optional

a) always if present

b) if TC1 is neither 0 nor 255, then reject the SIM (in accordance with subclause 5.10); see the note after the table

6. Interface
character

TD1

protocol type; indicator for the presence of interface characters, specifying rules to be used for transmissions with the given protocol type

always, if T=15 indicated in TDi (i>1)

a) always if present

b) identifying the subsequent characters accordingly

7. Interface
character
(specific)

TA2

not used for protocol T=0

optional

a) optional

b) ‑‑‑‑‑‑‑‑

8. Interface
character
(global)

TB2

parameter to calculate the programming voltage

never

the allowed value of TB1 above defines that an external programming voltage is not applicable

9. Interface
character
(specific)

TC2

parameters to calculate the work waiting time

optional

a) always if present

b) using the work waiting time accordingly

10. Interface
character

TDi

(i>1)

protocol type; indicator for the presence of interface characters, specifying rules to be used for transmissions with the given protocol type

optional

a) always if present

b) identifying the subsequent characters accordingly

(continued)

Table 5 (concluded): ATR

Character

Contents

sent by

the card

a) evaluation by the ME

b) reaction by the ME

11. Interface
character

TAi, TBi, TCi
(i>2)

characters which contain interface characters for other transmission protocols. If TD(i-1) indicates T=15, TAi is interpreted as global interface character

Always if TD(i-1) indicates T=15. Optional otherwise.

a) always

b) If T=15 is indicated in TD(i-1), TAi indicates:

XI clock stop indicator (b8 to b7)

UI class indicator (b6 to b1)

12. Historical
characters

T1,…,TK

contents not specified in ISO/IEC

optional

a) optional

b) ‑‑‑‑‑‑‑‑

13. Check
character

TCK

check byte (exclusive ‑ORing)

not sent if only T=0 is indicated in the ATR. If T=0 and T=15 are present and in all other cases, TCK shall be sent

a) optional

b) ‑‑‑‑‑‑‑‑

NOTE: According to ISO/IEC 7816‑3 [26], N=255 indicates that the minimum delay is 12 etu for the asynchronous half‑duplex character transmission protocol.

If ’01’ is indicated in TA1, PPS should be supported by the SIM to allow backward compatibility with existing MEs. For the interpretation of ’01’, see ISO/IEC 7816‑3 [26].

5.8.2 PPS procedure

Specifically related to this Technical Specification the PPS procedure according to ISO/IEC 7816‑3 [26], is applied, only if TA1 is not equal to ’11’ or ’01’, as follows:

a) for MEs only supporting default speed (F=372, D=1)

ME

————————————— Reset —————————————>

SIM

<————————————— ATR ——————————————

TA1 not = ’11’ or ’01’

PPSS =

‘FF’

PPS0 =

’00’

———————— PPS Request —————>

PCK =

‘FF’

PPSS =

‘FF’

<———————— PPS Response —————

PPS0 =

’00’

PCK =

‘FF’

Figure 1: PPS procedure

PPS Request and PPS Response consist of the three (3) characters PPSS, PPSO and PCK of which PPSS is sent first.

After this procedure the protocol T=0 and the parameters F=372, D=1 and N=0 shall be used.

b) for MEs only supporting enhanced speed (F=512, D=8)

ME

————————————— Reset —————————————>

SIM

<—————————————— ATR ——————————————

TA1 = ’94’

PPSS =

‘FF’

PPS0 =

’10’

———————— PPS Request —————>

PPS1 =

’94’

PCK =

‘7B’

PPSS =

‘FF’

<———————— PPS Response —————

PPS0 =

’10’

PPS1 =

’94’

PCK =

‘7B’

Figure 2: PPS procedure requesting enhanced speed values (F=512, D=8, see clause 5.8.3)

PPS Request and PPS Response consist of the four (4) characters PPSS, PPSO, PPS1 and PCK, of which PPSS is sent first.

After this procedure, the protocol T=0 and the parameters F=512, D=8 and N=0 shall be used.

5.8.3 Speed enhancement

If speed enhancement is implemented, the ME and the SIM shall at least support F=512 and D=8 in addition to F=372 and D=1. However, other values may also be supported. If the ME requests PPS using values other than those above then the PPS procedure shall be initiated accordingly.

The SIM shall support the default value (F=372 and D=1). If the speed enhancement is supported by the SIM it is mandatory that F=512 and D=8 is supported. However, the value in TA1 may even indicate a faster speed (F=512 and D=16). The SIM may also support other values between the default value (F=372 and D=1) and the values indicated in TA1. The SIM shall offer the negotiable mode, to ensure backwards compatibility with existing MEs. In the negotiable mode the SIM will use default values even if other parameters are offered in the ATR if the PPS procedure is not initiated.

The ME shall support the default value (F=372 and D=1). If the speed enhancement is supported in the ME it is mandatory to support F=512 and D=8. The ME may additionally support other values.

If the SIM does not answer the PPS request within the initial waiting time the ME shall reset the SIM. After two failed PPS attempts using F=512 and D=8 or values indicated in TA1, (no PPS response from the SIM) the ME shall initiate PPS procedure using default values. If this also fails (no PPS response from the SIM) the ME may proceed using default values without requesting PPS.

If the SIM does not support the values requested by the ME, the SIM shall respond to the PPS request indicating the use of default values.

5.9 Bit/character duration and sampling time

The bit/character duration and sampling time specified in ISO/IEC 7816‑3 [26], are valid for all communications.

5.10 Error handling

Following receipt of an ATR, which is not in accordance with this specification, e.g. because of forbidden ATR characters or too few bytes being transmitted, the ME shall perform a Reset. The ME shall not reject the SIM until at least three consecutive wrong ATRs are received.

During the transmission of the ATR and the protocol type selection, the error detection and character repetition procedure specified in ISO/IEC 7816‑3 [26], is optional for the ME. For the subsequent transmission on the basis of T=0 this procedure is mandatory for the ME.

For the SIM the error detection and character repetition procedure is mandatory for all communications.