Card Manufacturing has moved on from print-based technology to embrace
electronics manufacturing technologies producing reliable components
for electronic data interchange.
At the International Card Manufacturers Association convention held
in London in October 1997 I met one of Europe's major card manufacturers.
While we were chatting he reminded me that when we first met about 10
years ago I had asked him to describe his business. He reminisced how
proud he was about the quality of his printing, which he still is. Ten
years ago he told me all about his investment in the latest printing
machines he had bought and showed me around his printing department.
Now he explained how his business had changed so very radically and
described how his business might now be described as a "complex
electronics component manufacturing" business. He added that he
has had to re-address the skills of his staff to meet the need to supply
his customers with cards which operate reliably in worldwide electronic
payment systems.
He now realizes that his customers use cards as electronic keys to
a complete data system. Not only has he to produce good quality printing
to brand the products he produces for his customers, but he has to supply
cards with an integral electronic data interchange component.
The magnetic stripe is just as important a piece of engineering as
the terminals and data links.
If cards fail to read, the payment, transit or access control system
will not work!
This manufacturer, who also runs a card personalization bureau, now
realizes that he must ensure he supplies his customers with a consistent
and reliable product. Therefore he needs to control his quality from
an engineering standpoint as well as the aesthetic properties of the
product he supplies. He needs to ensure he is buying and laying down
good and reliable magnetic media. He needs to control the effectiveness
of that media throughout his processes and then ensure that his personalization
equipment is regularly calibrated to International Industry standards.
For the purpose of this article, I will confine myself to ISO data
recording, the ISO specification and how to measure the parameters set.
The methods of encoding / decoding are defined in ISO 7811/2 for low
coercivity and 7811/6 for high coercivity. The test methods are set
out in ISO 10373. This is the recognized world industry standards so
that so that magnetic readers can decode data encoded on the magnetic
stripe.
Typically up to 3 tracks are used:
Track 1 is encoded with up to 79 characters and is alpha numeric.
Track 2 is encoded with up to 40 characters and is numeric only.
Track 3 is encoded with up to 107 characters and is numeric only.
Tracks 1 and 3 are encoded at 210 bits per inch and track 2 at 75 bits
per inch. A magnetic stripe analyzer will measure this bit spacing.
The ISO specifications clearly describe that 6 bits and a parity check
are used to denote a character on track 1, whereas 4 bits and a parity
check are used to denote a digit character in tracks 2 and 3. A LRC
(longitudinal redundancy check) is used at the end of each data stream
to cross check that all data bits within the data stream are correct.
These checks can be confirmed by a suitable analyzer.
For readers to work effectively, it is important that each recorded
bit is properly spaced along the track (bit spacing). A reader will
synchronize its own electronic clocks to the same timing as the bit
cells which precede a data stream (i.e. before the start sentinel) or,
if read from the reverse direction, the cells which follow the end sentinel
and LRC. By separating the interval bit cells -zeros- before and after
the data from the interval bit cells within the mixed data stream we
can also examine the bit cells which are used by swipe readers to set
their electronic clocks.
The Barnes Mag-Tester provides a histogram of bit spacing for leading
and trailing clocks as well as the bit spacing within the data stream.
See exhibit (1): Note this shows track 2, similar histograms are provided
for tracks 1 & 3
Reader synchronization requirements dictate the need to test encoded
cards for correct position of start sentinel and to check that the end
sentinel is not too near the physical end of the card. These position
limits are defined in ISO specifications.
It is extremely important that the bit spacing is encoded to be as
uniform as possible along each track. Bit spacing variation expressed
as a ratio of one bit cell to the previous bit cell is known as jitter.
High jitter, i.e. large differences between successive bit cells, can
cause read / decode errors.
Low Coercivity particles are made of gamma ferric oxide and are needle
shaped with north and south poles at the ends. A well known problem
with LoCo media is that it is easy to erase by a simple household or
commercially available magnets.
The majority of financial cards and transit tickets used to date use
LoCo magnetic media, typically 300 Oersted. Card issuers receive frequent
complaints that cards do not work. Reduction of the costs associated
with managing this depends on identifying and attacking the causes.
A swipe reader may confirm whether the cards work or not. Use of an
analyzer will confirm why they do not work and provide the means to
address the problem.
Exhibit (2) shows a track by track summary whereas exhibits "A","B"
and "C" show the results of each track on the far right column
compared to the ISO specification limits. ( Print outs taken from Barnes
Mag-Tester 2000).
It is well known that VISA carried out research and found that typically
about 3% of magnetic stripe based transactions (amounting to many millions
of $) failed due to stray magnetic erasure-ladies' hand bag clasps being
one of the main causes.
Exhibit (3) shows the effect of passing a simple household magnet across
a 300 Oe LoCo card.
When the mag-stripe is corrupted by stray magnetic fields, transactions
have to be manually key entered. Manual key entry avoids the use of
any integral mag-stripe security features and is prone to error. Manual
key entry also offers opportunities to fraudsters and therefore there
is a new concerted effort on the part of all card issuers to improve
stripe reliability and thus reduce the need for key entry.
To improve reliability against magnetic erasure and to minimize the
number of key entry transactions, many financial card issuers are changing
to high coercivity.
Because of the higher cost of cards particularly those using both magnetic
stripe and chip technology (as used in France) it is essential that
all aspects of the card are more reliable.
HiCo particles are barium ferrite and are "plate" shaped.
The north and south poles are on the "flat" surfaces (rather
than at the pointed ends as in LoCo). HiCo materials also require much
more energy (write current) than LoCo materials to change the polarity
of and magnetize the particles. Typically 10 times more write current
is used for HiCo than LoCo materials.
The degree of resistance to change in direction of the magnetization
is known as coercivity. The greater the energy needed the higher the
coercivity. The gentleman who discovered this relationship was a Dane
called Oersted. The unit of measurement of resistance to magnetic change
was given the name :- Oersted.
HiCo has a coercivity between typically 2500 and 4000 Oe. ISO have
chosen a nominal value of 2750 Oe for their standard reference media.
HiCo Financial cards are gradually adopting the 2750 Oe "standard".
I referred earlier to how easy it is for normal household magnets to
erase LoCo media. HiCo, 2750 Oe, cards are resistant to similar magnetic
fields.
So far we have looked at the encoded cards and what should be tested
to ensure reliability for encoded cards in use. However it is vital
to ensure that the media itself is capable to accepting encoding and
fully meets the internationally recognized standards.
It is not enough for card manufacturers to rely on their vendors of
media for this because they make physical changes to the media when
they lay the tape and laminate. Secondly there are factors, as we will
see, where mag-tape apparently works well after it is encoded but has
other properties which prevent correct reading- these are media problems
which we need to look out for.
There are a number of important magnetic parameters which need to be
confirmed to ensure the media contributes to the effective use of cards
as a key to that electronic payment, transit or access control system.
The first of these is to ensure the media accepts encoding:
What is Saturation and What is the ISO Window Test?
If not enough current is used by the write head, then the magnetic
field will not reach all the particles to the full depth (thickness)
of the magnetic media. Magnetic media is said to be at saturation when
all the particles are fully magnetized.
The ISO specification lays down the criteria which must be used for
all media to be encoded and for readers to be set in order to read the
encoded data. These are set out in table 1 in ISO 7811-2 and 7811-6
under the ISO test method requirements of 10373.
Exhibits "X" and "Y" show a complete table 1 test
for LoCo and HiCo media respectively. Exhibit "Z" ( Print
outs taken from Barnes Mag-Tester 2000).
Are There Any New Risks Associated with HiCo?
Because of the plate-like shape of HiCo particles, high coercivity
media is much more difficult to manufacture. The uniformity of distribution
and alignment of the particles are important factors in ensuring that
additional "stray" fields are not produced by the media. Such
fields can result in false peaks and/or differences when reading in
a forward or reverse direction. These false peaks can be decoded as
a clock or data bit resulting in a failed read. A new test has been
added to table 1 for HiCo which checks the read signal waveform for
these problems-the "Waveform" test.
Waveform problems are unlikely to be seen when bad media is encoded
but put HiCo reliability at risk each time the card is read in use.
It is essential that media is tested for this potential problem-and
why Barnes recommends an extra "Reverse Waveform" test additional
to the ISO test procedures.
A suitable magnetic analyzer will readily identify these false peaks
or a non return to zero effect.
We have so far seen why it is important to test the magnetic media
for the factors we have covered in this article. There are a number
of other tests on offer with a Barnes Mag-Tester 2000 analyzer, e.g.
various repeat read tests, which offer the facility to simulate any
number of selected read passes.
ISO specifies the need to test for erasure performance, to test for
how evenly the magnetic particles are dispersed all along the track,
to test for resolution and demagnetization (which importantly confirms
the main reason for using HiCo media).
Do HiCo Encoded Cards Erase LoCo Encoded Cards?
Extensive tests have been carried out on the effect of placing HiCo
cards stripe to stripe with LoCo cards. Evidence points to the possibility
(probability) of marked deterioration in the quality of encoding on
LoCo cards. This deterioration is variable depending on the individual
characteristics of the HiCo and LoCo media.
The effect, however, on low coercivity magnetic stripe cards is uncontrollable.
Care must be taken and tests carried out at the manufacturing or personalization
stage to assess the risk of this phenomenon in order to take corrective
action.
The writer has carried out several experiments in controlled conditions
to show the effect of passing a HiCo (2750 Oe) encoded card stripe to
stripe against a number of various LoCo (300 Oe) encoded card. After
a single pass there was a small deterioration on both Jitter and Amplitude
readings on the LoCo stripe. However no effect was noticed on HiCo cards.
After repeating this test several times some LoCo encoding showed marked
deterioration to the extent that cards failed the ISO parameter tests
for both Jitter and Amplitude.
LoCo cards which are repeatedly inserted into a card wallets with LoCo
stripes in contact with HiCo stripes are therefore unlikely to read
reliably in field use.
Clearly card brands which retain the use of LoCo media, such as retail
loyalty cards, are vulnerable to increased incidence of erasure and
consequent delays at checkouts while account data is key entered, contra
to the trend and desire of issuers to reduce key entry.
Whether you are a card manufacturer, card personalizer or card issuer
you will need an analyzer or the facilities of a test laboratory to
understand and manage these issues and to defend your card base against
complaints This will enable you to prove that any contamination to the
data came from sources outside your control.
Card failures result in losses for banks and card issuers
Hopefully this article has made you more aware that accurate testing
of the media and encoding reduces wastage and minimizes both rejection
and field failures. This yields improvements in both productivity and
profitability for card manufacturers and issuers.
Faulty magnetic media or bad encoding is a critical area of risk for
both card personalization bureaus and card issuers. The expanding volume
of cards and their increasing cost, especially where cards utilize both
magnetic and chip technologies, clearly exacerbates this area of vulnerability.
It is vital therefore that you are equipped with magnetic stripe test/analysis
facilities to be able to test for all the ISO parameters effectively
for both media and encoding.
A good magnetic stripe analyzer will provide you with information (information
gives you power and control) as follows:
- The magnetic media from the tape manufacturers before manufacture
of bulk supplies.
- The magnetic performance of the media during and after card manufacture-media
can vary after lamination.
- The magnetic performance of the encoded data, keeping encoding machines
aligned and calibrated to the close tolerances specified by ISO for
newly encoded cards.
- The quality of encoding and diagnosis of problems on used cards,
including the ability to reconstitute data to test cut cards.
- The magnetic encoding on used cards to the wider tolerances specified
by ISO for cards returned after field use.
Card manufacturers and service bureaus who have installed appropriate
test equipment have benefited in a number of ways:
- They have a much better control of their product quality which leads
to better efficiency.
- They are able to use their test equipment for accurate vendor rating.
- They demonstrate to their customers their commitment to quality
which in turn creates greater loyalty, resulting in higher profitability.
- They can test to the relevant ISO parameters and can archive results
on PC hard disk (e.g. for ISO 9000).
Historically the evidence of card problems due to faulty magnetics
has been relatively scarce. One reason for this is that plastic cards
were traditionally used with manual swipe imprinters which in North
America and Europe have now been largely replaced by electronic point
of sale terminals. This increasing trend towards electronic transactions
has increased the awareness towards industry standards and the demand
for better control in manufacturing tolerances (media, cards, tickets
and encoding). This has led to more effective analysis equipment now
being available.
Major improvements have taken place within the ISO specifications to
include more precise definitions of test methods and standards. HiCo
materials are now available enabling great reductions in the traditional
electronic transaction failure rate due to accidental erasure. All this
has raised industry standards everywhere. In today's market, the cost
of card failure has moved from simply that attributable to replacing
cards to the open-ended burden of reestablishing market credibility.
Card manufacturers have had to move with the times from their traditional
printing business to meet the requirements of the market for card performance
and reliability which is critical to successful Electronic Data Interchange.
That is exactly what my friend from Europe recognized, and he now considers
himself running a more professional and valuable organization in the
eyes of his suppliers and his customers alike.
The key questions are:
- If you are a card manufacturer can you certify that all batches
of cards you manufacture and deliver to your customers conform for
magnetic stripe quality to ISO 7811/2 for LoCo and 7811/6 for Hico
according to ISO 10373 test methods?
- Can you supply your customers with certificates supported by test
results from a suitable analyzer which is calibrated by means of a
calibration card traceable to the ISO (PTB) reference standards for
both LoCo and HiCo ( 7811/2 & 7811/6)?
- Has the HiCo media been tested and can you certify, supported by
test results that the media has been tested particularly for waveform
distortions ( Ui6 test) in both forward and reverse directions?
If you are a card personalizer can you confirm:
- that all batches of encoded cards conform to ISO 7811/2 for LoCo
and 7811/6 for HiCo in accordance with ISO 10373 test methods to the
"new card" standards of encoding for each track?
- that you can supply your customers with certificates from suitable
analyzer which has been calibrated by means of a calibration card
traceable to the ISO (PTB) reference standards for both LoCo and HiCo
( 7811/2 & 7811/6)?
- that you can supply evidence that encoded HiCo cards have been tested
particularly for waveform distortions (Ui6 test) in both forward and
reverse directions?
In the words of one major player in card manufacture and systems in
America : "If you are not measuring what you are producing-you
ain't doing it right!"