Decode Distances The table below lists the typical and guaranteed scanning distances for
selected bar code sizes. The minimum element width (“X Dimension”,
“size” or "symbol density") is the width in mils of the narrowest element
(bar or space) in the symbol.
Typical Working
Ranges Guaranteed
Working Ranges
Symbol
Density /Bar
Code Type
/W-N Ratio
Bar Code
Content
/Contrast Near Far Near Far
6 mil
Code 39; 2.5:1 123
80% MRD 2.25 in
5.72 cm 4.50 in
11.43 cm 3.00 in
7.62 cm 4.00 in
10.16 cm
7.5 mil
Code 39; 2.5:1 ABCDEF
80% MRD 1.75 in
4.45 cm 6.25 in
15.88 cm 2.50 in
6.35 cm 4.75 in
12.07 cm
10 mil
Code 39; 2.5:1 FGH
80% MRD 1.25 in
3.18 cm 7.50 in
19.05 cm 2.00 in
5.08 cm 6.00 in
15.24 cm
13 mil
UPCA; 2.5:1 012345678905
80% MRD 2.00 in
5.08 cm 8.50 in
21.59 cm 2.50 in
6.36 cm 7.25 in
18.42 cm
20 mil
Code 39; 2.5:1 123
80% MRD 2.20 in
5.59 cm 12.00 in
30.48 cm Note 2 10.75 in
27.31 cm
55 mil (4)
Code 39; 2.5:1 CD
80% MRD 4.30 in
10.92 cm 24.00 in
60.96 cm Note 2 16.00 in
40.64 cm
Notes:
1. Contrast measured as Mean Reflective Difference (MRD) at 670 nm.
2. Near ranges on lower densities depend on the width of the bar code and the
scan angle.
3. Working range specifications at ambient temperature (23 C).
4. Retro-reflective label media used for 55 mil bar code.