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CT-BCS

Cardterminal basic command set for integrated circuit card applications.

This manpage describes the subset of the Cardterminal Basic Command Set (CT-BCS) used to control cardterminals with one or more integrated circuit card slots, without key pad and display. This manpage is not a complete specification of the CT-BCS, but a general overview of the most common functionalities.

The CT-BCS commands are constructed in compliance with ISO/IEC 7816-4 interindustry commands and are used to control cardterminal utilizing the CT-API function CT_data().

A CT-BCS command is an array of bytes that is sent to the cardterminal to perform an administrative action. The CT-BCS response is an array of bytes returned by the cardterminal that informs of the completion status of the action requested.

The following diagram shows the general structure of a CT-BCS command:

|<------------------------------------------>| 
|    Header (4 Bytes)     and body           | 
|      (mandatory)       (optional)          | 
|<----------------->|<---------------------->| 
|___________________|________________________| 
|CLA |INS |P1  |P2  |Lc  |Data          |Le  | 
|____|____|____|____|____|______________|____|

The following diagram shows the general structure of a CT-BCS response:

|<------------------------------>|<--------->| 
|           Body                    Trailer  | 
|        (optional)                (2 Bytes) | 
|                                 (mandatory)| 
|________________________________|___________| 
|Data                            |SW1-SW2    | 
|________________________________|___________|

The fields within a CT-BCS command and response are equivalent to those defined by ISO/IEC 7816-4:

Class. The CLA value used for CT-BCS commands is 0x20.

Instruction. Defines the action to be performed by the cardterminal.

Command parameters 1 and 2.

Length of command data field.

Length of expected data:

Case 1: No command data, no response data (no Lc and no Le).

Case 2: Command data, no response data (0<=Lc<=254 and no Le).

Case 3: No command data, response data (no Lc and 0<=Le<=254).

Case 4: Command data, response data (0<=Lc<=254 and 0<=Le<=254)

Status bytes. Completion status of the command.

The address value 0x01 (CT) shall be used as destination address (dad) given to CT_data() when sending CT-BCS commands (See CT_data (3)).

The following commands are present in every CT-BCS implementation:

Basic CT commands

Cardterminal Command INS Code
RESET CT 0x11
REQUEST ICC 0x12
GET STATUS 0x13
EJECT ICC 0x15

The following general return codes SW1-SW2 may occur:

General return codes

SW1-SW2 Description
0x6700 Wrong length
0x6900 Command not allowed
0x6A00 Wrong parameters P1, P2
0x6D00 Wrong instruction
0x6E00 Class not supported

Functional units are entities that can be addressed as target of CT-BCS commands. In some CT-BCS commands a target functional unit needs to be specified.

Functional units

Functional Unit Coding
CT kernel 0x00
CT/ICC slot 1 0x01
CT/ICC slot 2 0x02
CT/ICC slot 14 0x0E

Support for slots 2-14 depends on the cardterminal. Functional units for keypad and display are defined for some cardterminals but are not described here.

The RESET CT command asks the cardterminal to perform a reset of the specified functional unit. If the functional unit is the CT kernel, a software reset is carried out, meaning that all status information (f.i. information of inserted cards) is cleared and gathered again. For ICC functional units, an card reset is performed.

Optionally the answer to reset of the functional unit is returned in the response data.

A RESET CT command can be issued after initialization of the cardterminal or after the occurrence of a communication error.

The command structure is as follows:

0x20
0x11 (=RESET CT)
Functional unit:
0x00 = CT
0x01 - 0x0E = ICC Interface 1-14
Command qualifier:
In case P1 = 0x00:
0x00 = No response
In case P1 = 0x01 - 0x0E:
0x00 = No response data
0x01 = Return complete ATR
0x02 = Return Historical Bytes
Lc field
Empty
Le field
Empty or 0x00: return full length of requested information

The response structure is as follows:

Empty, ATR or Historical Bytes
Status Bytes

When functional unit is CT (0x00) the following status bytes can be returned:

0x9000
Reset successful
0x6400
Reset not successful

When functional unit is a ICC slot (0x01 - 0x0E) the following status bytes can be returned:

0x9000
Synchronous ICC, reset successful
0x9001
Asynchronous ICC, reset successful
0x6400
Reset not successful

The REQUEST ICC command asks the cardterminal to wait for the presence of an ICC on the specified cardterminal slot during a specified time limit. The command synchronously blocks the caller application unless time limit 0 is specified. When an ICC is presented it is automatically activated and reset.

The command structure is as follows:

0x20
0x12 (=REQUEST ICC)
Functional unit:
0x01 - 0x0E = ICC-Interface 1 - 14
Command qualifier: Request handling instructions for the CT

Lc field
Empty or length of subsequent data field
Data field
Empty (= immediate response required) or max. waiting time in seconds (1 byte, binary coding) for presenting the ICC

Le field
Empty or 0x00 = Return full length of requested information

The parameter P2 carries the request handling instructions for the CT. The value of P2 is constructed of two 4-bits subfields:

  • 0x0 = No meaning
  • Other values reserved for future use
  • 0x0 = No response data
  • 0x1 = Return complete ATR
  • 0x2 = Return Historical Bytes

The response structure is as follows:

Empty, ATR or Historical Bytes
Status Bytes

The following status bytes can be returned:

0x9000
Synchronous ICC presented, reset successful
0x9001
Asynchronous ICC, reset successful
0x6200
No card presented within specified time
0x6201
Card already present and activated
0x6400
Reset not successful
0x6900
Command with timer not supported

The GET STATUS command is used to gather cardterminal manufacturer information and ICC status information from the cardterminal. The information is represented by TLV (tag, length, value) encoded data objects. The tag of the data object to be retrieved is specified in the command and the value is returned in the response.

The command structure is as follows:

0x20
0x13 (=GET STATUS)
Functional unit:
0x00 = CT
Command qualifier: Tag of data object to be returned

Lc field
Empty
Data field
Empty
Le field
Hx00 = Return full length of requested information

The response structure is as follows:

Status information (only value field of data object)

Status Bytes

The following data objects are defined. Note that only value field is returned in the response:

•
Tag = 0x46
•
Length >= 15
•
Value:
CTM: Cardterminal manufacturer (5 bytes ASCII encoded). It consists of 2 bytes with the country code and 3 bytes with the manufacturer acronym
CTT: Cardterminal type (5 bytes ASCII encoded). The value is manufacturer dependant
CTSV: Cardterminal software version (5 bytes ASCII encoded). The value is manufacturer dependant

DD: Discretionary data (any number of bytes including 0)

•
Tag = 0x80
•
Length
•
Value: One ICC status byte per ICC slot in the cardterminal.

If b8-b1 = 0x00 then no ICC is present in the slot.

If b1 = 1 and ICC is present in the slot and the bytes b3-b2 indicate whether the ICC is electrically connected (value 10) or electrically disconnected (value 01).

The following status bytes can be returned:

0x9000
Command successful

The EJECT ICC command asks the cardterminal to deactivate the ICC. It must be used at the end of the communication with the card or when a irreparable communication error occur.

The command structure is as follows:

0x20
0x15 (=EJECT ICC)
Functional unit:
0x01 - 0x0E = ICC-Interface 1-14
Command qualifier: Eject handling instructions for the CT (0x00 for cardterminals without keypad and display)

Lc field
Empty or length of subsequent data field
Data field
Empty or time in seconds for removing the ICC
Le field
Empty

The response structure is as follows:

Empty

Status Bytes

The following status bytes can be returned

0x9000
Command successful
0x9001
Command successful, card removed
0x6200
Card not removed within specified time

ctapi (3).

The MKT (Multifunktionale KartenTerminals) specifications, available for download from Teletrust web site http://www.teletrust.de (link to URL http://www.teletrust.de) . In special the documents:

CT-API. Cardterminal Applications Programming Interface.

CT-BCS. Cardterminal Basic Command Set.

IC cards with synchronous transmission Part3: Usage of interindustry Commands.

ISO/IEC 7816: Identification cards - Integrated circuit(s) cards with contacts:

Interindustry commands for interchange.

This manual page was written by Carlos Prados <cprados@yahoo.com>.