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Codabar (USD-4, NW-7, and 2 of 7 code)

Codabar can encode the digits 0 through 9, six symbols (-:.$/+), and the start/stop characters A, B, C, D, E, *, N, or T. The start/stop characters must be used in matching pairs and may not appear elsewhere in the barcode. Codabar is used in libraries, blood banks, the overnight package delivery industry, and a variety of other information processing applications.
There is no checksum defined as part of the Codabar standard, but some industries (libraries, for example) have adopted their own checksum standards.  Many libraries use the following system which includes 13 digits plus a checksum; here is a description of the method used by Ameritech Library Services (Provo, Utah).


  • Digit 1 indicates the type of barcode:  2 = patron, 3 = item (book)
  • Digits 2-5 identify the institution
  • The next 8 digits (00010 586) identify the individual patron or item
  • Digit 14 is the checksum

To calculate the checksum, start with the total set to zero and scan the 13 digits from left to right:

  1. If the digit is in an even-numbered position (2, 4, 6…) add it to the total.
  2. If the digit is in an odd-numbered position (1, 3, 5…) multiply the digit by 2.  If the product is equal to or greater than 10, subtract 9 from the product.  Then add the product to the total.
  3. After all digits have been processed, divide the total by 10 and take the remainder.
  4. If the remainder = 0, that is the check digit.  If the remainder is not zero, the check digit is 10 minus the remainder.

What Size Should A Printed QR Code Be?

When a QR code is published it should be of a size that’s appropriate for the scanning environment it’s being put into. The finished printed size of the QR code will be dependent on:

  • The distance between the QR code and the scanning device – which determines the size of the QR code in the viewport of the phone camera
  • The size of the dots in the code – the more data you put into the code the smaller the dots become

Scan Distance

To effectively scan the QR code it should appear to be at least 1cm (0.4 inches) across in the viewport of the scanning device, and as the distance between the camera and the QR code increases, the size of the QR code will need to increase to compensate.

If you have a QR code on the side of a building it would need to
be very large because it’s going to be scanned from a long distance, however if it’s printed in a magazine then the scanning device will be held quite close to it so it can be much smaller.


For most smartphones the relationship between scan distance and minimum QR code size is approximately 10:1 so a 2.5cm (1 inch) QR code printed in a magazine will have a nominal effective scan distance of about 250mm (10 inches), and a QR code on a billboard 20 metres (65 feet) from the where a passer-by would be scanning it would probably need to be about 2 metres (6.5 feet) across. There’s a bit of latitude here depending on the sort of smartphone but 10:1 is a good rule of thumb for a well-lit black and white QR code being scanned front-on.

Simple Formula:Minimum QR Code Size = Scanning Distance / 10

If you have a poorly lit or obliquely positioned QR code, or a coloured one where the foreground/background colour contrast might not be optimal, you should probably reduce this ratio to 8:1 or less (ie; the QR code size should 1/8th or less of the scan distance).

QR Code Data Density

As mentioned above, the more data you put into the code the smaller the dots (the dark pixel squares) become as the QR code adjusts itself to increase its data storage capacity.

The density of the code is described by a version number that is based on the number of rows and columns of dots. A Version 1 QR code will have 21 rows and 21 columns of dots and the version number will then increase by 1 for every 4 extra rows and columns – a Version 2 QR code will have 25 rows and columns, a Version 3 will have 29 rows and columns, right through to a Version 25 that will have 117 rows and columns.

As the size of the dots decrease they become harder for the scanner in the smartphone to “see” so the QR code itself needs to be made larger in order for it to be reliably scanned.

Most QR codes containing just a website address end up being Version 2 QR codes with 25 rows and columns of data dots. I talked about keeping the size of the QR code in the viewport of the scanning to 1cm (0.4in) or better – with 25 rows and columns of dots in a “normal” QR code this would make each of the dots 0.4mm (0.016in) across as a minimum, and this is actually the “magic number” that makes a QR code reliably scannable.

It was probably a bit simplistic to say that the QR code image should be at least 1cm (0.4in) across in the viewport of the camera – what I should have said was that each of data dots should be at least 0.4mm (0.016in) across, and there’s how the data density of the QR code affects the its scanning reliability. A QR code with a high data density is going to have more rows and columns of dots in it, so each dot will be smaller relative to the size of the QR code itself. If the dots are too small then the QR code will be difficult to scan because the data dots are below the resolution limit of the scanning device.
















QR codes containing long URL’s (like Google Maps address URL’s) may result in up to a Version 6 or Version 7 QR code with 41 or 44 rows and columns of dots.

QR codes containing vCard contact details have notoriously high data densities and will result in Version 10 or Version 11 QR codes with more than 60 rows and columns of dots.

To keep each data dot at the recommended 0.4mm (or greater) when viewed in the viewport of the camera you will need to make the QR code image itself significantly larger.

HINT: Using a URL shortener to reduce the number of characters in a long URL will result in a code with larger dots and hence it can be reproduced at a smaller size without impacting scan reliability.

Calculating The Size

The recommended minimum size of the QR code image is determined by the scanning distance and the size of the data dots in the QR code, and can be calculated by first determining:

  • Distance Factor: Start of with a factor of 10 then reduce it by 1 for each of poor lighting in the scan environment, a mid-light coloured QR code being used, or the scan not being done front on.
  • Data Density Factor: Count the number of columns of dots in the QR code image and then divide that by 25 to normalise it back to the equivalent of a Version 2 QR code.
Better Formula:Minimum QR Code Size = (Scanning Distance / Distance Factor) * Data Density Factor


A QR code containg vCard contact details has resulted in a Version 10 QR code with 57 rows and columns of data dots. It’s to be printed on a business card in black and white and it’s expected that the scanning distance will be about 150mm.

Scanning Distance = 150mm (5.9 inches)
Distance Factor = 10
Density Factor = 57/25 = 2.28

Minimum Size = (150mm / 10) * 2.28 = 34.2mm (1.34 inches)

A QR code is to be placed behind the counter of a restaurant containing a simple link to a coupon download. The QR code is Version 2 so has 25 rows and columns of dots. The lighting is a bit dim and the scan distance will be 2.5m.

Scanning Distance = 2500mm (8.2 ft)
Distance Factor = 10 – 1 (for poor lighting) = 9
Density Factor = 25/25 = 1.0

Minimum Size = (2500mm / 9) * 1.0 = 277.7mm (0.91 ft)

A QR code containing a Google Maps location link is to be published in a magazine. This has resulted in a Version 6 QR code (41 rows and columns of data dots) and it will be printed in mid-blue to match the business colours. It’s expected that the scan distance will be about 200mm.

Scanning Distance = 200mm (7.9 inches)
Distance Factor = 10 – 1 (for use of colour) = 9
Density Factor = 41/25 = 1.64

Minimum Size = (200mm / 9) * 1.64 = 36.4mm (1.44 inches)

Test, Test, Test…

Regardless of the size of the QR code, the finished QR code should be tested thoroughly in its intended final setting to make sure that it works at that size.

Smart card

Smart card


Smart Card Parameters
Product Name smart card
Material PVC / ABS / PP / PETG / Clear PVC
Size 85.5mmx54mm (round corner) or 90mmx50mm(round or or on demand)
Print offset printing / silk printing / digital printing
MOQ 100pcs
Lamination overlay laminated into glossy, or matt or frosted
Artwork design .ai/ .cdr/ .psd/ .pdf/ .indd/ .eps etc
Crafts QR code/embossing/hot foil stamping/varnish oil finish/laser engraving/die cut etc
Lead time 8-10 days
Delivery time 3-6 days
Payment term T/T,Paypal,Western Union,MoneyGram
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Samples sample production accept
free produced sample business card by Airmail
Package details 500pcs/tray,2000pcs/carton or 250pcs/inner box,2500pcs/carton
Application smart card
Weight 12kg per 2000pcs
Certificate ISO 9001 quality guaranteed



Contact smart card chip
Logic security IC ISO Protocol Capacity
SLE4442/5542 ISO7816 256 bits
SLE4428/5528 ISO7816 1024 bits
FM4442 ISO7816 256 bits
FM4428 ISO7816 1024 bits
BL7742 ISO7816 256 bits
BL7428 ISO7816 1024 bits
Storage IC ISO protocol Capacity
AT24C01 ISO7816 1024 bits
AT24C02 ISO7816 2048 bits
AT24C04 ISO7816 4096 bits
AT24C16 ISO7816 16k bits
AT24C64 ISO7816 64k bits
AT24C128 ISO7816 128k bits
AT24C256 ISO7816 256k bits


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EM4102 ISO7815 64 bits
EM4305 ISO7815 512 bits
EM4450 ISO7815 1k bits
TK4100 ISO7815 64 bits
T5577 ISO7815 330 bits
HITAG1 ISO11784/85 2048 bits
HITAG2 ISO11784/85 256 bits
HITAG S256 ISO11784/85 2560 bits
HITAG S2048 ISO11784/85 32048 bits
High frequency 13.56MHz ISO protocol Capacity
FM11RF08 ISO14443A 1024 bits
ISSI 4439 ISO14443A 1024 bits
NXP Mifare 1k S50 ISO14443A 1024 bits
NXP Mifare 4k S70 ISO14443A 4069 bits
I CODE SLI ISO15693 1024 bits
I CODE SLI-S ISO15693 2048 bits
I CODE SLI-L ISO15693 512 bits
I CODE SLI-X ISO15693 2048 bits
Mifare Ultralight ISO14443A 64 bits
Mifare Ultralight C ISO14443A 192 bits
Mifare PLUS 2K ISO14443A 2048 bits
Mifare PLUS 4K ISO14443A 4069 bits
Mifare Desfire 2K ISO14443A 2048 bits
Mifare Desfire 4K ISO14443A 4069 bits
Mifare Desfire 8K ISO14443A 8192 bits
TI256 ISO15693 256 bits
TI2048 ISO15693 2048 bits
Ultra high frequency ISO protocol Capacity
NXP UHF-6C ISO18000-C 512 bits




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welcome to visit Cardsfly Technology Limited

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