Juniper Allegro CE Owner's Manual page 258

Code ID
The scanner is capable of returning a Code ID character(s) for the bar
code that is scanned. If a Code ID is selected, the Code ID character(s)
is placed before the bar code data and the prefix character (if
enabled).
There are two types of Bar Code ID's: Symbol and AIM. The Symbol
Code ID is a single character code. The AIM Code ID contains three
characters, a bracket ("]") is followed by a code character and a
modifier character.
Symbol Code ID
A = UPC-A, UPC-E, UPC-E1, EAN-8, EAN-13
B = Code 39, Code 32
C = Codabar
D = Code 128, ISBT 128
E = Code 93
F = Interleaved 2 of 5
G = Discrete 2 of 5, or Discrete 2 of 5 IATA
J = MISI Plessey
K = UCC/EAN-128
L = Bookland EAN
M = Trioptic Code 39
N = Coupon Code
Prefix and Suffix
The Prefix, Suffix 1, and Suffix 2 character selection pull-down
window lists the characters that can be used as a prefix or suffix.
Only the prefix or suffix pull-down windows that are enabled are
shown.
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