What colors can a barcode be?
What data canb be encoded in a barcode?
How do I put a return tab or other field exit character at the end of a barcode?
Which Barcode is the best to use for my new application?
Why do you not recommend 'Extended Code 39'
How do I identify a barcode?
What are 1D barcodes?
What are 2D barcodes?
What is PDF417?
What are the different types of scanner?
What is the maximum number of characters I can put in a barcode?
Random length data- peoples names?
Can I buy a 'light pen' type of barcode scanner?
What characters can I put in a barcode?
How can I print barcodes?
| Barcode: Frequently Asked Questions
What characters can a barcode encode
It depends on the symbology. All barcodes can encode the numerics.
Here is a summary of the capabilities of some popular codes...
| ||Numeric||Alpha||Symbols||Full ASCII set
|Regular Code 39||Yes ||Capitals only||a few(4)||no
|Interleaved 2 from 5||Yes ||No||No||No
|Code 128||Yes ||Yes||Yes||Yes
When would i choose barcode x
One of the oldest barcode symbologies but still very much alive today.
Advantages: Very common barcode. All scanners can read it reliably.
Can encode Alphabetic characters. Easy barcode to print.
Can be printed from wide range of proprietary graphical and labeling software
or by means iof a simple font.
Disadvantages: Cannot easily encode lower case alphabetic characters
unless 'Extended Code 39' is used. This is not recommended because it introduces
much ambiguity and confusion.
Summary. Code 39 is useful for small blocks of numeric or
alphanumeric data where the case of the alpha characters doesn't
Low cost CCD scanners have a maximum width of about 60mm (2.35" inches).
Check that the final barcode size is not too wide for your scanning equipment.
Consider using Code 128 as an alternative for new applications.
Avoid using 'Extended Code 39'.
Interleaved 2 from 5
Use this format when you want the smallest barcode for numeric characters.
Advantages. Very small and compact.
Disadvantages. Cannot encode any characters other than numerics. Special
care required when setting up the decoding hardware otherwise decoding can
be unreliable. For new applications Code 128 may be a better choice.
Should be one of your prime candidates for new applications.
Advantages. Can encode the whole ASCII character set reliably with a compact barcoode.
Disadvantages. Hard to think of any! Not quite as simple to print as Code 39.
Use PDF417 when the size of a conventional Code 128 barcode with the same data
would be too wide for easy scanning. Depending on circumstances this may be around
10-20 data characters.
Advantages: Can encode many more characters than conventional barcodes.
Disadvantages: Not space efficient for small amounts of data. Not as resistant
to damaged, obliteration and scuffing as 1D barcodes.
Most other barcode symbologies are used in particular industries. For example
the EAN/UPC/JAN symbologies are mainly used in retail to ID goods at the checkout.
Summary: If you are working in an industry or sector where a particular barcode
symbology is used this should be your first choice unless there are reasons not to.
When are 2D barcodes best
Use a 2D barcode when a 1D barcode holding an equivalent amount of data
becomes unpractically large. The lowest cost CCD scanners can read barcodes to
a width of about 60mm. If your barcode are wider than this consider using
a 2D barcode like PDF417. Barcodes wider than 60mm can be read by some CCD and
most Laser Scanners but the cost of the scanning hardware is higher. The
systems analyst must decide which is best solution based on individual
how do I produce a 2D barcode.
There is special barcode printing and label printing software on the market.
Barcode Man recommends using Bartender software produced by Seagull Systems.
Seagull have a good track record when it comes to barcode and labeling
software. In many cases they wrote the print driver for the Printer Manufacturer
so they have an insight into a vast range of office and specialist label
Barcode Man uses this software for our own 'in house' printing and are
distributors of it. [link] The software prints the regular 1D barcodes too.
All the barcodes on this web page were produced by bartender.
How much data can barcodes of each type hold. Which type of barcode
should I choose?
Do I work in an industry where a particular type of barcode is generally used?
Are there any contraints on final size of barcode. For example barcodes on
small parts or jewellery?
Is the barcode likely to be subject to degradation. For example scuffing or
Is the capital cost of the scanning equipment an important issue.
How many data characters do I want to encode in the barcode. Is the data
Numeric, Alpha numeric or Full ASCII
upto 10... use 1D Barcode. Symbologies Code 39 (preferred) or Code 128
10-20 Use Code 128. If the data is wholy numeric then Interleaved 2/5 can be used.
more than 20 use a 2D barcode. Symbology PDF417
Examples of the quantity of info in each type of barcode
Code 39, Interleaved 2 from 5, Code 128, PDF417
My Name+0123 Alpha numeric containing characters (space and plus)
particular way . cul
The barcodes most often seen on
grocery and other products are One Dimensional. They encode data by using a
combination of bars and spaces of varying widths. The early 'Light Pen'
type of barcode scanners had to be manually swept across the whole width
of the barcode and it was therefore necessary to increase the height of the
bars to make scanning easier and more reliable. Modern barcode scanners scan
the barcode automatically and so the same information can be encoded in a
barcode of shorter height
???/How to print pdf417?????
Conventional barcodes come in a range of styles (symbologies) like 'Code 39',
'Interleaved 2 from 5' or 'Code 128'. Many of
these symbologies came from competing manufacturers and industries trying to
capture their sector of the market. As technology moved forward many of these
symbologies were superseded by better symbologies. Nevertheless many of the
older barcode symbologies remain in use in niche areas where it would
be difficult to change.
It uses multiple rows of stacked
bars to encode a greater amount of data while still retaining a manageble
barcode size and shape.
They have been developed in response to the increasing
demand for higher capacity. From the technical point of view 2D barcodes
have become possible as the older pen type scanner have been replaced by
CCD and Laser auto scanners.
>Can you tell me if it is possible to scan a combination of characters , such as
>SHIFT TAB (reverse TAB), using the Code 128 specification. I can\'t seem to get
>a straight answer from any source. I can currently code an algorithm to include
>single sequence control characters, but not the combinations.
To solve your problem you need to decide on the hardware platform the
scanner is to be attached to and the type of interface you are using.
You also need to be clear about the difference between 'characters',
'keystrokes' and 'scancodes'.
The following information only applies to IBM PC or compatible hardware
using a Keyboard wedge interface. Other platforms or interfaces are
different. The character set is assumed to be ASCII.
All barcode symbologies (including Code 128) define the way 'characters'
are encoded. Barcode specifications have nothing to say about keystrokes
or scancodes and cannot encode them directly.
A scanner first decodes the barcode into characters then converts the
characters into keystrokes then converts the keystrokes into scancodes.
If you need a barcode to produce a SHIFT TAB combinational keystroke you
cannot do this directly because it is a 'keystroke' not a 'character'.
Confusion often arises because TAB _is_ an ASCII character. However when
you press the TAB key the 'scancode' sent to the computer bears no
relationship to the ASCII TAB- the computer converts from the scancode
to the ASCII TAB.
So how is it done?
In order to overcome all these problems we developed a special device we
call 'The Mule'. The Mule creates a string of scancodes which enables
you to emulate ANY key or combination of keys on a PC keyboard.
Here is a worked through example how to create a SHIFT TAB keystroke.
Other keystrokes are worked out in a similar fashion.
List in detail how the keystroke is entered manually. Be aware a PC
keyboard sends a scancode each time a key is pressed and each time a key
is released. Each key sends a different scancode. Sometimes there are
more than one key that can be used (for example there are two shift
keys) in this case either can be used- I have chosen the left-shift.
1: Left shift down
2: Tab down
3: Tab up
4: Left shift up
Convert to the appropriate scancode
1: 12 (Left shift down)
2: 0D (Tab down)
3: F0 0D (Tab up)
4: F0 12 (Left shift up)
String all the scancodes together to give...
This is the scancode sequence needed to generate a SHIFT TAB keystroke
on a PC.
To use The Mule you need to send this sequence as a string of ASCII
characters. So the Mule interprets the characters as scancodes they need
to be surrounded by the ASCII and characters.
To read this from a barcode you need a scanner with a RS232 interface
(so you can connect direct to The Mule) and a barcode symbology that can
encode the and characters- Code 128 is a good choice.
This sounds complicated but unfortunately it is the only way I know to
do it. Please email again if anything is not clear. These links will be
PC keyboard scancodes...
Code 128 information...