BARR/SPOOL manual

Appendix B. ASCII and EBCDIC Standards

The PC uses the ASCII (American Standard Code for Information Interchange) coding system to define the correspondence between the graphic symbols we see on paper and on screen to the hexadecimal codes manipulated in the computer. By comparison, a mainframe or AS/400 assumes the EBCDIC (Extended Binary-Coded Decimal Interchange Code) coding system between the graphic symbols and the hexadecimal codes used in the computer.

Both the ASCII and EBCDIC standards include control codes that do not have a graphic representation. These codes are used for control functions by printers and communication protocols. The control codes are represented symbolically by two- and three-character abbreviations. For example, the control code for End of Transmission is represented as EOT.

When printing ASCII files on EBCDIC printers, BARR/SPOOL must translate the codes from ASCII to EBCDIC. When printing EBCDIC files on ASCII printers, BARR/SPOOL must translate the files from EBCDIC to ASCII.

The tables in sections B.5 and B.6 show the standard ASCII-to-EBCDIC and EBCDIC-to-ASCII translations. Section 9.1 describes how to modify the standard translation tables.

• B.1 Printing ASCII Files on EBCDIC Printers

• B.2 Printing EBCDIC Files on ASCII Printers

• B.3 EBCDIC and ASCII Translation

• B.4 ASCII-to-EBCDIC Translation Table

• B.5 EBCDIC-to-ASCII Translation Table

• B.6 Legend of Characters

B.1 Printing ASCII Files on EBCDIC Printers

BARR/SPOOL translates ASCII files to EBCDIC files when printing to S/370 channel attached printers.

Each ASCII line ends with the carriage return character. Line Feed (LF), Form Feed (FF), and Delete (7F) characters are discarded. Horizontal Tab (HT) characters produce the standard spacing assumed by the IBM PC.

BARR/SPOOL translates from the ASCII character set to the EBCDIC character set. See Section B.4 for a description of the ASCII-to-EBCDIC Translation Table.

B.2 Printing EBCDIC Files on ASCII Printers

A mainframe or AS/400 uses the EBCDIC coding system. The data in each line is translated from EBCDIC to ASCII as described in Section B.5, EBCDIC-to-ASCII Translation Table.

Each line received from the host computer provides line feed and carriage control information as described in the following table:

B.3 EBCDIC and ASCII Translation

During data translation, the representation for a symbol in one coding system is converted to the representation for that symbol in the other coding system. In many cases, an identical symbol exists in both coding systems so translation is straightforward. For example, the letter A is represented as hexadecimal 41 in ASCII and C1 in EBCDIC.

In a few cases, an identical symbol does not exist in both coding systems but an equivalent character can be substituted. For example, the EBCDIC Logical Not (¬) symbol is represented by the ASCII circumflex (^), the alternate representation for this symbol.

In other cases, an equivalent symbol does not exist because all graphic symbols do not appear in both the ASCII and EBCDIC coding systems. In these cases, the software substitutes a question mark (?) for the symbols. For example, when converting from EBCDIC to ASCII, the EBCDIC hexadecimal 62 does not have an equivalent representation in ASCII.

The default tables in the BARR/SPOOL program do not translate any control codes. Instead, question marks (?) are substituted for control codes. Translate control codes to Control codes is the default option. The default tables are shown in this appendix. You can alter the translation tables to meet your application’s requirements. Refer to section 9.1 for more information about modifying the translation tables.

Extended ASCII Codes: The translation tables allow you to use extended ASCII codes for 80-FF. On the PC keyboard, extended ASCII characters can be displayed by pressing ALT and the decimal code for the symbol. Refer to the ASCII code pages in your DOS manual for a list of ASCII symbols and their decimal codes.

B.4 ASCII-to-EBCDIC Translation Table

The ASCII codes are defined in the American Standard Code for Information Interchange publication ANSI X3.4-1986 from the American National Standards Institute, Inc., 1430 Broadway, New York, NY 10018.

In the table above, the first column contains ASCII hexadecimal codes that are associated with a graphic or control symbol given in the third column. EBCDIC codes are obtained by matching for the same graphic in the IBM EBCDIC standard. The right half of the table (80-FF) is a copy of the left half (00-7F), which causes the parity bit to be ignored in translation between ASCII and EBCDIC.

B.5 EBCDIC-to-ASCII Translation Table

The EBCDIC codes are defined in the IBM publication, System 370 Reference Summary, GX20-1850.

In the table above, the first column contains EBCDIC hexadecimal codes that are associated with a graphic or control symbol given in the third column. ASCII codes are obtained by matching for the same graphic in the ASCII standard. The double question marks (??) indicate characters which are not available in ASCII. These characters will be translated to an ASCII question mark (?). Two EBCDIC-to-ASCII Tables can control EBCDIC-to-ASCII translation on printer and punch streams. The following list shows how Table 2 differs from Table 1.

If your printer supports these symbols, using Table 2 makes the symbols print on the PC the same way as on a mainframe. Most PC printers support printing these characters.

B.6 Legend of Characters

Characters and symbols which display in the translation tables (B.4 and B.5) are listed below.