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!"