Magnetic Stripe Glossary
- A -
Access control is a method of using equipment and/or services to control access or egress of customers or employees to secure locations. Magnetic cards are often issued to these individuals, and certain magnetic messages confer access to specific groups of entry points at specific times.
AC erase See demagnetize.
Aiken 2-frequency coherent phase
Known as F2F, this is the encoding technique used for cards meeting ISO standards ISO/IEC-7811-2 (see figure 7) and ISO/IEC-7811-6. Each "0" bit has a flux change at the beginning and end but not in the middle. A "1" is similar except that there is a flux transition in the middle of the bit.
Amplitude is a measure of the signal strength of an encoded magnetic message. Its unit of measure is UR, the ISO reference signal amplitude.
ANSI is the American National Standards Institute( 11 W. 42nd St., 13th Floor, New York NY 10036 USA). ANSI created the original X4.16 specification predating ISO/IEC-7811-2. ANSI is a source for purchasing ISO specifications. ISO specifications are available from ANSI. Check http://www.ansi.org for more information.
American Standard Code for Information Interchange; this is a standard format for alphanumeric data in which 8 bits (with 1 additional parity bit) are used to represent letters and numbers. Banking and related cards use a 6-bit subset (with 1 additional parity bit) of this standard. Refer to ISO/IEC-7811-2, table 4.
- B -base film
A base film is a thin plastic sheet upon which a magnetic slurry is coated.
Barium Ferrite is generally the primary magnetic material used for high coercivity magnetic cards.
A binder is a material that is added to a slurry of magnetic material that will provide the magnetic stripe with toughness and durability once the slurry is oven dried.
A bit is an abbreviation for binary digit, a representation of two possible conditions, generally a digital "1" or a digital "0". Bits are grouped together to form characters such as nibbles, bytes or words. Bits are generally encoded on magnetic cards in Aiken 2-frequency coherent phase encoding.
Bit density is a measure of the number of bits encoded on magnetic tape per unit of distance (millimeter or inch). On banking and financial cards encoded to ISO standards, track 2 is encoded at 2.95 bits per millimeter (75 bits per inch); tracks 1 and 3 are 8.27 bits per millimeter (210 bits per inch).
- C -character
A character is one alphabetic or numeric symbol that is formed by joining individual bits to form intelligible data.
A clock is a signal or pulse that is issued coincident with the presence of valid data at the output of an F2F decoder. Data is usually valid on the falling edge of the clock.
Coercivity, measured in Oersteds (Oe.), is very loosely defined as the magnetic field required to encode or erase a magnetic stripe. Ordinary low coercivity magnetic stripes (often called loco) are rated at 300 Oersteds; some others are in the range of 600-650 Oe. High coercivity stripes (often called hico or high energy) are generally in the range of 1250-4000 Oe. Bank and financial stripes average around 2750 Oe. High coercivity tapes are more resistant to accidental erasure.
A core is the magnetic frame (usually metallic) upon which turns of copper wire are wound to form a magnetic read or write head. A core is "C" shaped, and the opening in the "C", across which the magnetic lines of flux jump, is usually in the range of 12.7-51 um (0.0005-0.002").
Current is the movement of charged particles through a conductor, usually electrons through a copper wire. Current is measured in amperes or fractions of an ampere. Generally, dozens or hundreds of milliamperes must be passed through the coil of a magnetic head in order to encode data onto a stripe.
- D -
DC erase See demagnetize.
A decoder, usually an F2F decoder, transforms a TTL compatible (0 or 5 volt) F2F encoded waveform into a data signal and a separate synchronous clock signal. Decoders generally function over a wide range of perhaps 100 to 5000 bits per second.
To demagnetize would be to remove from a magnet or magnetic stripe any preponderance of magnetization in any particular orientation. Generally, the magnet is subjected to a strong alternating magnetic field (such as a bulk tape eraser) which is gradually withdrawn. The magnet is then said to be "AC erased". Otherwise, subject the magnet to a magnetic field that is constant, not alternating; the magnet is then said to be "DC erased". AC or DC erased magnetic stripes do not produce an output signal in a magnetic read head.
The demagnetization test is a test for high coercivity magnetic stripes, and is part of table 1 in ISO/IEC-7811-6. The demagnetization test attempts to measure the stripe's resistance to accidental erasure. Accidental erasure can be caused by magnetized handbag clasps, magnetized tools, refrigerator magnets etc.
A drop-in is a spot on a magnetic stripe where excess magnetic material is present such that the signal amplitude increases briefly. A drop-in is caused during manufacture of the stripe.
A drop-out is a spot on a magnetic stripe where the signal amplitude dips or goes to zero. Drop-outs can be caused by pinholes (a spot with no magnetic material), dirt, etc. which result from manufacturing defects.
density See bit density.Back to Top
- E -
To emboss is to press a tool into the surface of a plastic card in order to form a raised character. This raised character may be read visually and may be used with an imprinter to record a copy of this embossed data. With electronic data capture today, embossing is becoming less important at the point of sale.
To encode is to use a magnetic recording head to encode or write magnetic data on a stripe. The head produces alternating zones of north-south and then south-north magnetization. These alternating zones are formed into bits. Writing is the same as encoding.
Encoding testing is to check the signal amplitude, noise, waveform, density and bit spacing on a magnetic stripe. ISO testing is performed to ISO/IEC-7811-2 or -6. For a more detailed description of encoding quality and characteristics please refer to Q-Card brochure "Card Testing Reduces Losses and Improves Customer Satisfaction".
The end sentinel is the character encoded on a magnetic stripe just after the data and just before the LRC check character. For ISO tracks 2 and 3 the end sentinel is 11111. For ISO track 1 the end sentinel is 111110 (a ? character). These data patterns are when reading in the forward direction.
An error is an incorrect data bit read from a magnetic stripe. An actual error may have been encoded, or the card reader may simply read it incorrectly. Errors generally cause parity errors or LRC errors.
erase See demagnetize.
The erase test is a test for low or high coercivity magnetic stripes, and is part of table 1 in ISO/IEC-7811-2 and -6. The erase test attempts to measure if a magnetic stripe can be fully erased and to check the residual signal amplitude after erasure. A low residual signal is desirable.
An extra peak is defined in ISO/IEC-7811-6 and is an unwanted flux change on a high coercivity stripe caused by defects in the stripe itself. Extra peaks may cause read errors in either reading direction.
- F -
A flat area is defined in ISO/IEC-7811-6 and is a failure on a high coercivity stripe for the encoded signal to return to zero flux in between flux transitions. The flat area is caused by defects in the stripe itself and may produce read errors in the reverse reading direction.
A flux transition is a change in the magnetization on a magnetic stripe from north-south to south-north or vice versa. This reversal of magnetization causes a reversal in the output voltage from a magnetic read head and can be detected by a read circuit. This is sometimes called a flux change.
FRPI, flux reversals per inch, is a unit of density.
FRPMM, flux reversals per millimeter, is a unit of density.
- G -gamma ferric oxide
Gamma ferric oxide (iron oxide) is effectively rust. It is the magnetic component of a 300 Oersted magnetic stripe.
The gap is the opening in the "C" shaped core of a magnetic read or write head. Magnetic lines of flux bridging the gap induce voltage in a read head or produce flux changes when using a write head. The gap length across the "C" is usually in the range of 12.7-51 um (0.0005-0.002"). The gap width determines the encoded track width on the magnetic stripe. Typically ISO gap width is between 2.54 mm and 3.18 mm (0.100-0.125") although some special purpose heads feature gap widths of 6.3 mm (0.25") or more.
- H -head
A magnetic head is an electronic component for reading or encoding magnetic information. It is composed of a core, winding, optional case and output terminals or leads. Read heads may be used for any coercivity stripe. Write heads must be designed to handle the anticipated coercivity; write currents are typically 5-100 mA peak-to-peak for low coercivity and 100-2500 mA peak-to-peak for high coercivity. Write current also depends upon the number of turns in the winding (inductance), core material etc.
hico See coercivity.
high coercivity See coercivity.
- I -ISO
ISO is the International Organization for Standardization (1 Rue deVarembe, 1211 Geneva 20 Switzerland), a worldwide standards body that develops and maintains magnetic stripe card standards as well as many other standards. For more information on ISO standards contact the standards organization in your country. Details on the standards organization in your own country may be found at
ISO/IEC-7811-2 is the ISO recording technique specification for low coercivity identification cards. It covers stripe testing, encoding testing and many other factors. See ISO above for more information.
ISO/IEC-7811-6 is the ISO recording technique specification for high coercivity identification cards. It covers stripe testing, encoding testing and many other factors. See ISO above for more information.
ISO/IEC-10373 (parts 1-5) is the ISO document that describes test methods to be used to test identification cards. Part 2 is the section most devoted to magnetic stripes.
An inflection point is a spot near the x-axis on a magnetic signal waveform where the curve changes direction. Inflection points generally occur on digital "1's" and "O's" at 2.95 bits per millimeter (75 bits per inch) but only on the zeros at 8.27 bits per millimeter (210 bits per inch). The presence of a strong evidence of these inflection points generally means that the stripe has good resolution.
- J -jitter
Jitter is a change of bit length or half-bit length from one bit to the next. A change of bit length from one bit to the next is called "bit-to-bit" jitter. A change of the half bit length from one bit to the next is called "sub-interval" jitter. For instance a change of bit length from 100 to 105 would be 5% positive jitter. A change from 100 to 90 would be 5% negative jitter.
- K -
- L -
loco See coercivity.
low coercivity See coercivity.LRC
An LRC, longitudinal redundancy check, character is a character at the end of the stripe after the data and end sentinel. If the LRC does not match (a logical calculation must be done) the data on the card, there has been a read error.
Lapping film is a thin plastic sheet coated with aluminum oxide or other abrasive. The film is used to polish a magnetic head during the production process or to refurbish the head after substantial use. Nine micron film may be used for a rough polish and three micron for a final polish.
Loading refers to the amount or percentage of magnetic material present in a slurry prior to coating. Higher loadings produce more amplitude but may reduce the percent of binders; less binders may reduce durability.
- M -
- N -
NIST (National Institute of Standards & Technology) used to be named NBS (National Bureau of Standards) and provided secondary reference tape to the magnetic card industry. This function is now performed by PTB (Physikalisch-Technische Bundesanstalt, Braunschweig Germany).
- P -POS terminal
POS (point of sale) terminals are magnetic card (and/or IC card) readers with accessory display, keypads and microprocessors. These terminals are used to charge and/or authorize retail merchant sales.
The primary standard is a tape that is based upon the original master standard reference tape at NIST. Its amplitude at saturation is exactly 100% UR. Secondary standard reference cards are sold by PTB in Germany; these cards may be used to calibrate magnetic stripe analyzers.
Profile is a measure of the flatness of a magnetic stripe in a direction perpendicular to the long (top) edge of the card. Profile is measured in microns or microinches. The profile of the stripe can be concave or convex depending upon the type of stripe and construction of the card. The edges of the stripe can protrude. A bad profile can cause separation between parts of the stripe and parts of the magnetic head gap, causing reading and encoding failures.
PTB (Physikalisch-Technische Bundesanstalt, Lab 1.41, Bundesallee 100, D-38116, Braunschweig, Germany) is the German national standards laboratory. They were, until 2009 responsible for providing low coercivity RM7811-2 secondary reference cards and high coercivity RM7811-6 secondary reference cards. That responsibility now lies with Q-Card, in Sunbury, Pennsylvania, USA.
PVC, polyvinyl chloride, is the most popular material for making bank and financial cards. Due to the development of IC cards, optical cards and other innovations other materials may be used in the future. Some cards are being produced in polyester, polycarbonate, and there is even a biodegradeable card made of starch. PVC is easy to emboss, and this has been an advantage. A disadvantage not shared by polyester is PVC's low melting temperature.
- Q -
- R -
Read is a process of using a magnetic head to detect flux changes on a stripe and to convert these changes to binary data.
A reader is a device composed of a magnetic head, electronic circuitry and a case. It is used to read magnetic data from a stripe.
Record is a verb and is similar to write or encode.
A reference card is a card that produces a known amplitude at saturation. Primary standard reference cards or tape are held by PTB in Germany. PTB sells secondary standard reference cards that can be used to calibrate magnetic stripe analyzers. PTB is responsible for providing low coercivity RM7811-2 secondary reference cards and high coercivity RM7811-6 secondary reference cards.
Remanance is the extent to which the stripe remains magnetized after the removal of a saturating magnetic field. This remaining field is called residual magnetization. Higher remanance will yield a higher amplitude encoded signal. Generally, remanance, loading and thickness of the magnetic layer determine signal amplitude.
residual magnetization See remanance above.resolution
Resolution is a measure of the signal amplitude of a magnetic stripe at higher density versus the signal amplitude at lower density. Amplitude generally falls off at higher densities. The test densities used are usually 8 FRPMM (200 FRPI) and 20 FRPMM (500 FRPI). The resolution is said to be the amplitude at the high density divided by the amplitude at the lower density. This yields a factor from 0-1. It can be converted to a percentage by multiplying by 100. Lower resolution increases jitter and is undesirable.
The resolution test is a test for low or high coercivity magnetic stripes, and is part of table 1 in ISO/IEC-7811-2 and -6. The resolution test attempts to check higher density performance. See resolution above.
RM7811-2 is a low coercivity secondary standard reference card with a known signal amplitude at saturation. It is sold by PTB in Germany.
RM7811-6 is a high coercivity secondary standard reference card with a known signal amplitude at saturation. It is sold by PTB in Germany.
- S -saturation
Loosely, saturation is when a magnetic stripe has been fully magnetized and produces the absolute highest output signal amplitude. A saturation plot or curve, showing signal amplitude as a function of write flux, goes from zero to a peak at saturation and then declines slowly at high level of fluxes.
A secondary standard reference card is a calibration card of known signal amplitude at saturation that is traceable to the primary and master standards. See RM7811-2 and RM7811-6.
A sentinel is a special character encoded on a magnetic stripe. See end sentinel and start sentinel.
A slurry is a mixture of magnetic particles along with solvents, diluents, dispersants, binders etc. The slurry is coated onto a base film and oven dried.
SRM3200 tape was the original master standard reference tape, with signal amplitude of 100% UR at saturation. SRM3200 was once sold by NBS (later NIST). A substitute tape is now available from PTB in Germany.
Stripe testing is to check the window, resolution, erase, demagnetization and waveform on a magnetic stripe. ISO testing is performed to ISO/IEC-7811-2 or -6. For a more detailed description of the ISO stripe test please refer to Q-Card brochure "Testing Magnetic Stripes to Worldwide Standards Improves Card Quality".
- T -
tape See stripe.
A track is a location for linearly encoded data on a magnetic card. Track location is normally located a set distance from the top (closest long edge) edge of the card. ISO tracks are numbered 1, 2 and 3. Airline tickets have the same track locations as bank cards but also possess a track 4. There is also a proprietary track 0 between track 1 and the top of the card for Watermark Magnetics (registered trademark of Thorn-EMI). Other popular track locations is central track, midway between both long edges, on tickets such as British Rail. Centerlines for ISO tracks 1, 2 and 3 are approximately 7.06 mm, 10.36 mm and 13.92 mm respectively (0.278", 0.408" and 0.548"). Airline track 4 centerline is approximately 17.48 mm (0.688") from the top of the card.
A transport is a mechanism for moving a magnetic card. Transports are usually motorized and contain belts and rollers for moving the cards.
- U -
- V -
- W -waveform test
The waveform test is a test for high coercivity magnetic stripes, and is part of table 1 in ISO/IEC-7811-6. The waveform test encodes a stripe with digital zeros at 2.95 BPMM (75 BPI) and then reads this waveform to determine if "extra peaks" or a "flat area" are present as described in figure 6 of ISO/IEC-7811-6. Also see extra peaks and flat area.
Magnetic tape is applied to plastic cards. This technique is too expensive for use on paper cards; therefore, magnetic slurry is wet coated directly onto the paper stock and then oven dried.
The window test is a test for low coercivity or high coercivity stripes, and is part of table 1 in ISO/IEC-7811-2 and -6. The window test encodes the stripe at 8 FRPMM (200 FRPI) at two specific currents, Imin and Imax. The resulting signal amplitude is checked; it must be within specified limits.
Window calibration or calculation is a process of using a secondary standard reference card, RM7811-2 or RM7811-6, to calibrate a magnetic stripe analyzer. Two write currents, Imin and Imax, are determined, and UR, the ISO reference signal amplitude, is equated to a specific output voltage from the read head and read amplifiers. This allows the stripe analyzer to compare cards against the performance of the secondary standard reference card.
write See encode.Back to Top
- X -X4.16
X4.16 was the predecessor to ISO/IEC-7811-2. It was developed by the ANSI X3B10 technical committee.
- Y -
- Z -