Tally Genicom T5023, T5023+ ASCII code

Encryptions/Codes Programming interface (General)

14 T5023/5023+ - Programming Guide

ASCII code

A code table specifies how the printable characters and control commands, for

example, for document ejection and carriage return are encrypted binarily in the

computer or printer. The encryption is expressed by a corresponding hexadeci-

mal or decimal number. A certain character then lies in hexadecimal notation or

in the decimal representation, for example, in the range hex 00 to hex FF or de-

cimal 0 to decimal 255 (8- bit encryption).

Examples:

With the document printerand with most computers the basis for the encryptions is

the code system ASCII ( AmericanSt andard Code for Information Interchange),

which onlydiffers in certain characters for special foreign languages (national ASCII

table). The ASCII code is encryptedvia 7 bits, whereby 128 different meaningsare

possible.

Escape sequences / CSI sequences

As the ASCII table providesfewer control codes than print functions, the commands

for theprinter normally consist of a sequence of two or more ASCII characters. Such

a code sequenceis always preceded by the encryption of the control code ESC (Es-

cape) (ASCII code27 (decimal) or 1B (hexadecimal). This signals to the printer that

the encryptions following ESC are to be interpre ted as commands for the printer.

There are two kinds of code sequences for the document printer:

– ESC ...

Code sequences, which begin with ESC or the appropriate encryption, are

called ESC sequences.

– CSI ... = ESC [ ...

Code sequences introduced with CSI (Control Sequence Introducer) are

called CSI sequences. CSI sequences are introduced with encryptions of

the character sequence “ESC [” and concluded with the encryption of two

Character Meaning Decimal Hex

ESC

Letter big A

Letter small a

Number 4

Line Feed

Escape