Chapter 10: Bar Code Commands for 9-Pin Printers112
where parameter m designates the number of characters which will follow in the data. If you
wish to include a check digit, enter the ASCII character @ (64 Dec, 40 Hex) at the end of the
data.
Postnet Bar Code Command
Postnet bar coding is used by the United States Post Office for sorting mail by automated
equipment. It incorporates a coding system using five bars and four spaces for each digit.
Select/Print Postnet Bar Code Data Command
The command
ESC DLE C P
1
[data]
selects Postnet bar codes and initiates the printing of the zip code + 4 data which you enter as
part of the command. Each digit of data can be any ASCII character from 0 to 9 (48 to 57 Dec,
30 to 39 Hex). The data must be the full ZIP + 4 code.
Postnet Parameter P
1
Parameter P
1
tells the printer how many bytes of bar code data to expect. Its value can be any
ASCII character from NUL to DC4 (1 to 20 Dec, 01 to 14 Hex): any values for P
1
outside this
range will cause the data to be ignored.
The print density for Postnet bar codes will be 240 dpi. Printing is accomplished in two print
passes with a 1/144" line feed. The bar height will be as follows:
High Bar: 16/144" (eight dots in two passes)
Low Bar: 6/144" (three dots in two passes)
To include the check digit, enter the ASCII character @ (64 Dec, 40 Hex) at the end of the data.