ASCII/EBCDIC TABLES

ASCII:  (American Standard Code for Information Interchange) The data alphabet used in IBM PCs that determines the composition of the 7-bit strings of zeros and ones representing each character (alphabetic, numeric, and special).

EBCDIC: (Extended Binary Coded Decimal Interchange Code) The data alphabet used in all IBM computers (except the PC) that determines the composition of the 8-bit string of zeros and ones, representing each character (alphabet, numeric, and special).

Computers use internal binary numbers to represent both text and numeric data.  It is usually the responsibility of the program processing the data to distinguish between text (character) and numeric data.  Among the various computer manufacturers, two standard code sets have emerged that specify the relationship between an internal binary number and the character that it represents.

The two code sets are EBCDIC and ASCII. EBCDIC is used on most IBM computers. The only exception is the IBM PC family of computers.  ASCII is used by most other computer manufacturers.

The IBM 2780/3780 RJE protocols specify that text files are to be transmitted using the EBCDIC code set.  This means that IBM PCs, which use ASCII, must convert text data from ASCII to EBCDIC in order to send it to the remote system. The data then arrives at the remote system in EBCDIC. This is just fine for IBM computers, but other computers must convert the data from EBCDIC to ASCII.

Sometimes, a computer that uses the ASCII code set changes this code set a little.  ASCII specifies the character equivalents for only the first 128 characters of the code set.  Many manufacturers have used the remaining 128 values to provide an extended ASCII code set.  Since these extended codes are not standardized, the FastSync^® 3780 program gives you a way to customize the translation tables (code sets).

The normal translation table used by the FastSync 3780 program is XLAT.TBL.  You can specify an alternate translation table by using a special ".xlat(TranslationFileName)" as a command line option.

When the FastSync program is loaded into the computer, it searches for the file XLAT.TBL in the directory containing your program's executable (EXE) file. If the file is not found, or if the program cannot load the file, the default character translation tables embedded in the program code are used.

You can modify the translation tables or create entirely new translation tables with the program XLAT.EXE.  Click here for Customizing your ASCII and/or EBCDIC Tables.

When you change either the original ASCII or EBCDIC Table (that comes on your program's distribution disk), you write over the default table, xlat.tbl. Since you may later want to go back and use this standard (default) table, you should copy xlat.tbl to some other name, like xlat.old. You can later revert to the default table by copying the file back to xlat.tbl.