ISO/IEC 7811-7:2004

Identification cards — Recording technique — Part 7: Magnetic stripe — High coercivity, high density

ISO/IEC 7811-7(2004) is one of a series of International Standards describing the characteristics of identification cards. It is the purpose of ISO/IEC 7811-7 to provide criteria to which cards shall perform and to specify the requirements for such cards used for international interchange. It takes into consideration both human and machine aspects and states minimum requirements. ISO/IEC 7811-7 specifies requirements for a high coercivity magnetic stripe (including any protective overlay) on an identification card, the encoding technique and coded character sets. This encoding technique provides for a card capacity of approximately 10 times that of a card conforming to ISO/IEC 7811-6. The number of tracks has been increased to six, each track being approximately half the width of tracks conforming to ISO/IEC 7811-6, located so that readers designed to read these high density tracks will also be able to read cards conforming to ISO/IEC 7811-2 and ISO/IEC 7811-6. Data is encoded in eight-bit bytes using the MFM encoding technique. Data framing is used to limit error propagation, and error correction techniques further improve reliability of reading. ISO/IEC 7811-7 specifies: the conditions for conformance, physical characteristics for the card (warpage and surface distortions) and the magnetic stripe area (location, height and surface profile, roughness, adhesion, wear and resistance to chemicals), the signal amplitude performance characteristics of the magnetic stripe, the encoding specification including technique (MFM), angle of recording, bit density, flux transition spacing variation and signal amplitude, the data structure including track format, use of error correction techniques, user data capacity for ID-1, ID-2 and ID-3 size cards, and decoding techniques, and the location of encoded tracks. ISO/IEC 7811-7, together with a standard for test methods, provides for interchange between various types of identification card processing devices and systems.

Cartes d'identification — Technique d'enregistrement — Partie 7: Bandeau magnétique — Haute coercitivité, haute densité

General Information

• Status: Withdrawn
• Publication Date: 29-Jul-2004
• Withdrawal Date: 29-Jul-2004
• ICS: 35.240.15 - Identification cards. Chip cards. Biometrics
• Technical Committee: ISO/IEC JTC 1/SC 17 - Cards and security devices for personal identification
• Drafting Committee: ISO/IEC JTC 1/SC 17/WG 1 - Physical characteristics and test methods for ID-cards
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 25-Aug-2014

Relations

• Revised: ISO/IEC 7811-7:2014 - Identification cards — Recording technique — Part 7: Magnetic stripe — High coercivity, high density
• Effective Date: 10-May-2012

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 7811-7
First edition
2004-07-15


Identification cards — Recording
technique —
Part 7:
Magnetic stripe — High coercivity, high
density
Cartes d'identification — Technique d'enregistrement —
Partie 7: Bandeau magnétique — Haute coercitivité, haute densité




Reference number
ISO/IEC 7811-7:2004(E)
©
ISO/IEC 2004

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ISO/IEC 7811-7:2004(E)
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ISO/IEC 7811-7:2004(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Conformance . 1
3 Normative references . 2
4 Terms and definitions. 2
5 Physical characteristics of the identification card . 4
5.1 Magnetic stripe area warpage. 5
5.2 Surface distortions . 5
6 Physical characteristics of the magnetic stripe.6
6.1 Height and surface profile of the magnetic stripe area. 6
6.2 Surface roughness. 8
6.3 Adhesion of stripe to card. 8
6.4 Wear of magnetic stripe from read/write head. 8
6.5 Resistance to chemicals . 8
7 Performance characteristics for the magnetic material. 8
7.1 General. 8
7.2 Testing and operating environment. 8
7.3 Signal amplitude requirements for magnetic media . 9
8 Encoding technique. 11
9 Encoding specification. 12
9.1 Angle of recording . 12
9.2 Nominal bit density . 12
9.3 Flux transition spacing variation. 12
9.4 Signal amplitude requirements. 13
9.5 Bit configuration . 13
9.6 Direction of recording. 13
9.7 Leading and trailing clock bits . 13
10 Data structure. 13
10.1 Track format . 14
10.2 Coding for error detection and correction. 15
11 Decoding. 18
12 Location of encoded tracks . 18
Annex A (informative) Read compatibility of magnetic stripes (ISO/IEC 7811-6 and ISO/IEC 7811-7). 20
Annex B (normative) Signal amplitude measurements . 21
Annex C (informative) Magnetic stripe abrasivity . 22
Annex D (informative) Static magnetic characteristics. 23
Annex E (informative) Reed-Solomon code references. 25


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ISO/IEC 7811-7:2004(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees established
by the respective organization to deal with particular fields of technical activity. ISO and IEC technical
committees collaborate in fields of mutual interest. Other international organizations, governmental and non-
governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO
and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 7811-7 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 17, Cards and personal identification.
ISO/IEC 7811 consists of the following parts, under the general title Identification cards — Recording
technique:
 Part 1: Embossing
 Part 2: Magnetic stripe — Low coercivity
 Part 6: Magnetic stripe — High coercivity
 Part 7: Magnetic stripe — High coercivity, high density


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ISO/IEC 7811-7:2004(E)
Introduction
This edition is new and was prepared by JTC 1/SC 17/WG1 Physical characteristics and test methods for ID
cards. Portions of this International Standard are identical to ISO/IEC 7811-2 and ISO/IEC 7811-6, however
the user is encouraged to review the entire International Standard. The major differences between this
International Standard and ISO/IEC 7811-2 and ISO/IEC 7811-6 are listed below.
1. The bit density has increased from 8,27 bits/mm (track 1,3) and 2,95 bits/mm (track 2) to 40 bits/mm for all
tracks which results in 234 bytes of user data per track for an ID-1 size card.
2. The encoding technique referred to as MFM is used in place of F2F. This change doubles the data storage
density for the same minimum transition spacing with only a small reduction in the self-clocking ability.
3. The 3 tracks have been replaced by 6 tracks that are approximately half the width so that they occupy the
same space on the card. These are located so that readers designed to read the high density tracks will
also be able to read cards conforming to ISO/IEC 7811-2 and ISO/IEC 7811-6.
4. Data is distributed in frames with synchronisation characters to aid in error recovery, and there is a CRC for
each frame and a track CRC. Data recorded on each track is independent from other tracks (error detection
and correction for each track is on the same track), even though it may be only part of the message on the
card.
5. Error detection and correction is included using a shortened Reed-Solomon code. The amount of error
correction is fixed for all card sizes.
6. The magnetic stripe area extends completely to the left and right edge of the card.
7. In Table 1, test density values have changed, the resolution requirement has changed from 0,7 to 0,8, the
test for Waveform has been deleted, and Overwrite has been added to the requirements.
8. The maximum coercivity in Table D.1 of informative Annex D has been changed from 335 kA/m (4200 Oe)
to 250 kA/m (3125 Oe).
Notes in this International Standard are only used for giving additional information intended to assist in the
understanding or use of the standard and do not contain provisions or requirements to which it is necessary to
conform in order to be able to claim compliance with this standard.

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INTERNATIONAL STANDARD ISO/IEC 7811-7:2004(E)

Identification cards — Recording technique —
Part 7:
Magnetic stripe — High coercivity, high density
1 Scope
This part of ISO/IEC 7811 is one of a series of standards describing the characteristics for identification cards
as defined in the definitions clause and the use of such cards for international interchange.
This part of ISO/IEC 7811 specifies requirements for a high coercivity magnetic stripe (including any protective
overlay) on an identification card, the encoding technique and coded character sets. It takes into consideration
both human and machine aspects and states minimum requirements.
Coercivity influences many of the quantities specified in this part of ISO/IEC 7811 but is not itself specified.
The main characteristic of the high coercivity magnetic stripe is its improved resistance to erasure. This is
achieved with minimal probability of damage to other magnetic stripes by contact while retaining read
compatibility with magnetic stripes as defined in ISO/IEC 7811-2.
This standard provides for a card capacity of approximately 10 times that of a card conforming to
ISO/IEC 7811-6. The number of tracks has been increased to 6, each track being approximately half the width
of tracks conforming to ISO/IEC 7811-6, located so that readers designed to read these high density tracks will
also be able to read cards conforming to ISO/IEC 7811-2 and ISO/IEC 7811-6. Data is encoded in 8 bit bytes
using the MFM encoding technique. Data framing is used to limit error propagation and error correction
techniques further improve reliability of reading.
It is the purpose of this series of standards to provide criteria to which cards shall perform. No consideration is
given within these standards to the amount of use, if any, experienced by the card prior to test. Failure to
conform to specified criteria should be negotiated between the involved parties.
ISO/IEC 10373-2 specifies the test procedures used to check cards against the parameters specified in this
part of ISO/IEC 7811.
NOTE  Numeric values in the SI and/or Imperial measurement system in this part of ISO/IEC 7811 may have been
rounded off and therefore are consistent with, but not exactly equal to, each other. Either system may be used, but the
two should not be intermixed or reconverted. The original design was made using the Imperial measurement system.
2 Conformance
A prerequisite for conformance with this part of ISO/IEC 7811 is conformance with ISO/IEC 7810. An
identification card is in conformance with this part of ISO/IEC 7811 if it meets all mandatory requirements
specified herein. Default values apply if no others are specified.
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ISO/IEC 7811-7:2004(E)
3 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO/IEC 4287-1, Surface roughness — Terminology — Part 1: Surface and its parameters
ISO/IEC 7810, Identification cards — Physical characteristics
ISO/IEC 10373-1, Identification cards — Test methods — Part 1: General characteristics tests
ISO/IEC 10373-2, Identification cards — Test methods — Part 2: Cards with magnetic stripes
4 Terms and definitions
For the purposes of this part of ISO/IEC 7811, the terms and definitions given in ISO/IEC 7810 and the
following apply.
4.1
primary standard
set of reference cards established and maintained by Physikalisch-Technische Bundesanstalt (PTB) that
represent the values of U and I designated RM7811-7
R R
4.2
secondary standard
reference card designated RM7811-7 that is related to the primary standard as stated in the calibration
certificate supplied with each card
NOTE  Secondary standards can be ordered from Physikalisch-Technische Bundesanstalt (PTB), AG. 2.52 -
Bundesallee 100, D-38116 Braunschweig, Germany. The source of secondary standards will be maintained at least until
2005.
4.3
unused un-encoded card
card possessing all the components required for its intended purpose, which has not been subjected to any
personalization or testing operation, and which has been stored in a clean environment with no more than 48
hour exposure to day-light at temperatures between 5 °C to 30 °C and humidity between 10 % to 90 % without
experiencing thermal shock
4.4
unused encoded card
card according to 4.3 that has only been encoded with all the data required for its intended purpose (e.g.
magnetic encoding, embossing, electronic encoding)
4.5
returned card
card according to 4.4 after it has been issued to the card holder and returned for the purpose of testing
4.6
flux transition
location of the greatest rate of change with distance of the magnetization
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ISO/IEC 7811-7:2004(E)
4.7
reference current
I
R
minimum recorded current amplitude under the given test conditions that causes, on the reference card, a
readback signal amplitude equal to 80 % of the reference signal amplitude U at a density of 20 flux
,
R
transitions per millimetre (508 flux transitions per inch) as shown in Figure 6
4.8
reference flux level
F
R
flux level in the test head that corresponds to the reference current I

R
4.9
test recording currents
two recording currents defined by:
I = Recording current corresponding to 2,2 F
min R
I = Recording current corresponding to 2,5 F
max R
4.10
individual signal amplitude
U
i
base-to-peak amplitude of a single readback voltage signal
4.11
average signal amplitude
U
A
sum of the absolute values of the amplitude of each signal peak (U ) divided by the number of signal peaks (n)
i
for a given track over the length of the magnetic stripe area
4.12
reference signal amplitude
U
R
maximum value of the average signal amplitude of a reference card corrected to the primary standard
4.13
physical recording density
number of flux transitions per unit length recorded on a track
4.14
bit density
number of data bits stored per unit of length (bits/mm or bpi)
4.15
bit cell
distance for a data bit nominally the reciprocal of the bit density (see Figure 8)
4.16
average bit cell
B
a
product of bit cell length and sum of the actual distances for all flux transition intervals on a track divided by the
sum of the nominal distances for all flux transition intervals on the track
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ISO/IEC 7811-7:2004(E)
4.17
local average bit cell
B
a6
comparison reference for a given flux transition interval equal to the nominal L1 distance multiplied by the sum
of the actual distances for the previous six flux transition intervals divided by the sum of the nominal distances
for the previous six flux transition intervals (L1 * (Σ actual)/(Σ nominal))
4.18
demagnetization current
I
d
D C current value that reduces the average signal amplitude to 80 % of the reference signal amplitude (U ) on
R
a secondary reference card that has been encoded at a density of 40 ft/mm (1016 ftpi) at a current of I
min
4.19
L
1
short distance between adjacent flux transitions nominally equal to 1 times the bit cell
4.20
L
2
medium distance between adjacent flux transitions nominally equal to 1,5 times the bit cell
4.21
L
3
long distance between adjacent flux transitions nominally equal to 2 times the bit cell
4.22
FSC
frame synchronization character
4.23
CRC
cyclic redundancy check
4.24
CP
column parity
4.25
U
F
magnitude of the individual element at 20 flux transitions per mm frequency of the Fourier spectrum for a given
track over the length of the magnetic stripe area
5 Physical characteristics of the identification card
The identification card shall conform to the specification given in ISO/IEC 7810.
WARNING — The attention of card issuers is drawn to the fact that information held on the magnetic
stripe may be rendered ineffective through contamination by contact with dirt and certain commonly
used chemicals including plasticizers. It should also be noted that any printing or screening placed
on top of the magnetic stripe must not impair the function of the magnetic stripe.
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ISO/IEC 7811-7:2004(E)
5.1 Magnetic stripe area warpage
Application of a 2,2 N (0.5 lbf) load evenly distributed on the front face opposite the magnetic stripe shall bring
the entire stripe within 0,08 mm (0.003 in) of the rigid plate.
5.2 Surface distortions
There shall be no surface distortions, irregularities or raised areas on both the front and the back of the card in
the area shown in Figure 1 that might interfere with the contact between the magnetic head and magnetic
stripe.
Dimensions in millimetres (inches)
2,54 (0.100)
maximum
Top reference edge
Distortion-free
area
19,05 (0.750)
minimum

Figure 1 — Distortion-free area on card with magnetic stripe

If a raised signature panel area is located on the front or back of the card, then it shall be no closer to the top
edge of the card than 19,05 mm (0.750 in).
NOTE  Raised areas and distortions on other areas of the card may cause card transport problems with magnetic
stripe processing equipment resulting in reading or writing errors.
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ISO/IEC 7811-7:2004(E)
6 Physical characteristics of the magnetic stripe
6.1 Height and surface profile of the magnetic stripe area
The magnetic stripe area is located on the back of the card as shown in Figure 2.
Dimensions in millimetres (inches)
5,54 (0.218)
max
Top reference edge
Minimum magnetic Magnetic stripe area a
stripe width (W)
For use of tracks H1 to H3: a = 11,89 (0.468) min
For use of tracks H1 to H6: a = 15,95 (0.628) min

Figure 2 — Location of magnetic material
6.1.1 Surface profile of the magnetic stripe area
The maximum vertical deviation (a) of the transverse surface profile of the magnetic stripe area is shown
below. See Figures 3, 4 and 5. The slope of the surface profile curve shall be limited to: -4a/W < slope < 4a/W.
When the bending stiffness value (see ISO/IEC 7810) for the card is 20 mm or more then the surface profile
limits are:
Minimum stripe width As shown in Figure 3A As shown in Figure 3B
W = 6,35 mm (0.25 in)
a ≤ 9,5 µm (375 µin) a ≤ 5,8 µm (225 µin)
W = 10,28 mm (0.405 in)
a ≤ 15,4 µm (607 µin) a ≤ 9,3 µm (365 µin)


When the bending stiffness value (see ISO/IEC 7810) for the card is less than 20 mm then the surface profile
limits are:
Minimum stripe width As shown in Figure 3A As shown in Figure 3B
W = 6,35 mm (0.25 in) a ≤ 7,3 µm (288 µin) a ≤ 4,5 µm (175 µin)
W = 10,28 mm (0.405 in) a ≤ 11,7 µm (466 µin) a ≤ 7,3 µm (284 µin)

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ISO/IEC 7811-7:2004(E)

W
W
a
a
A B

Figure 3 — Surface profile


Abrupt drop
Permitted Not permitted
Permitted Not permitted

Figure 4 — Surface profile examples


Irregular profiles as shown may result in poor quality encoding.

Figure 5 — Irregular surface profile examples

6.1.2 Height of the magnetic stripe area
The vertical deviation (h) of the magnetic stripe area relative to the adjacent surface of the card shall be:
-0,005 mm ( - 200 µin) ≤ h ≤ 0,038 mm (1500 µin)
Spiking in the profile caused by the material “squirt out” in hot stamping is not part of the stripe. It shall not
extend above the magnetic stripe area height (h) as defined above.
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ISO/IEC 7811-7:2004(E)
6.2 Surface roughness
The average surface roughness (R ) of the magnetic stripe area shall not exceed 0,40 µm (15.9 µin) in both
a
the longitudinal and transverse directions. Refer to ISO/IEC 4287 Part 1.
6.3 Adhesion of stripe to card
The stripe shall not separate from the card under normal use.
6.4 Wear of magnetic stripe from read/write head
Average signal amplitude (U ) and individual signal amplitude (U ) are measured before and after 2 000 wear
A i
cycles and shall result in:
U ≥ 0,60 U and U ≥ 0,80 U
A after A before i after A after

6.5 Resistance to chemicals
Average signal amplitude (U ) and individual signal amplitude (U ) are measured before and after short term
A i
exposure (as defined in the referenced Test Method document) shall result in:
U ≥ 0,90 U and U ≥ 0,90 U
A after A before i after A after

Average signal amplitude (U ) and individual signal amplitude (U) are measured before and after long term
A i
exposure (24 hours) to acid and alkaline artificial perspiration, as defined in the referenced Test Method
document.
and
U ≥ 0,90 U U ≥ 0,90 U
A after A before i after A after

7 Performance characteristics for the magnetic material
The purpose of this section is to enable magnetic interchangeability between card and processing systems.
Media coercivity is not specified. The media's performance criteria, regardless of coercivity, is specified in
clause 7.3.
7.1 General
This method uses a reference card whose material is traceable to the primary standard (see Clause 4). All
signal amplitude results from the use of the secondary reference card must be corrected by the factor supplied
with the secondary reference card.
7.2 Testing and operating environment
The testing environment for signal amplitude measurements is 23 °C ± 3 °C (73 °F ± 5 °F) and 40 % to 60 %
relative humidity. When tested under otherwise identical conditions, the average signal amplitude measured at
40 ft/mm (1 016 ftpi) shall not deviate from its value in the above test environment by more than 15 % after
5 minute exposure over the following operating environment range:
temperature -35 °C to 50 °C (-31 °F to 122 °F)
relative humidity 5 % to 95 %

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ISO/IEC 7811-7:2004(E)
7.3 Signal amplitude requirements for magnetic media
The requirements for recording characteristics of the card are shown in Table 1, and Figures 6 and 7. The
media’s performance requirements specified in section 7.3 shall be met in order to achieve improved
resistance to erasure, and to enable magnetic interchange between card and processing systems. The
properties in Annex D are intended as guidelines for magnetic material. Annex D is informative and shall not
be used as performance criteria for cards.
Table 1 — Signal amplitude requirements for unused unencoded cards
Description Density Test recording Signal Requirement
ft/mm (ftpi) current amplitude result
Signal amplitude 20 (508) I U 0,8 U ≤ U ≤ 1,2 U
min A1 R A1 R
Signal amplitude 20 (508) I U U ≤ 1,26 U
min i1 i1 R
Signal amplitude 20 (508) I U U ≥ 0,8 U
max A2 A2 R
Signal amplitude 40 (1016) I U U ≥ 0,65 U
max i2 i2 R
Resolution 40 (1016) I U U ≥ 0,8 U
max A3 A3 A2
Erasure 0 I , DC U U ≤ 0,03 U
min A4 A4 R
Extra pulse 0 I , DC U U ≤ 0,05 U
min i4 i4 R
Demagnetisation 0 I , DC U U ≥ 0,64 U
d A5 A5 R
Demagnetisation 0 I , DC U U ≥ 0,54 U
d i5 i5 R
Overwrite 20 (508) I U U ≤ 0,03 U
max F6 F7 F6
40 (1016) I U
min F7
The slope of the saturation curve shall never be positive between I and I
min max
It is not permissible to combine the above requirements mathematically.
NOTE The density of 20 ftpmm converts to 508 ftpi in this standard and to 500 ftpi in ISO/IEC 7811 part 2 and part 6.
These 2 are not different in principle. To ensure compatibility at the higher recording density the more accurate
conversion is used in this part of the standard.

U
A1
130
U
A2
Readback 120
voltage
100
U
R
(%U )
R
80
60 Example curve
40 Reference card curve
corrected to the primary
20
standard
Recording current
I I I
R min max

Figure 6 — Saturation curve example showing tolerance area
NOTE  The curve defines the primary standard response (on a card). The window parameters define a card that will
be functional in the machine readable environment.
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ISO/IEC 7811-7:2004(E)

flux transitions flux transitions
base line
flux transitions flux transitions

Figure 7 — Waveform example
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ISO/IEC 7811-7:2004(E)
8 Encoding technique
The encoding technique for each track shall be Modified Frequency Modulation (MFM) recording for which the
conditions are:
-a flux transition shall be written at the centre of each bit cell containing a ONE,
-a flux transition shall be written at each cell boundary between adjacent bit cells containing ZEROS.
See Figure 8.

t t t t t t t t t t t
0 0 0 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1 1 1
0 0 1 0 1 1 1 0 0 1
L L L
3 1 2
t, indicates bit cell boundaries

Figure 8 — Examples of MFM encoding
The data shall be recorded as a synchronous sequence of characters without intervening gaps.
NOTE 1 Recording with a write current which is less than I may result in poor quality encoding.
min
NOTE 2 MFM is the same as the FM technique described in ISO/IEC 7811-6 except that clocking flux transitions for 1
bits have been removed. This results in a loss of some of the self-clocking feature with FM encoding and requires more
accuracy for flux transition intervals. With this technique there may not be a flux transition at the bit cell boundary.
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