System Administration Guide
Chapter 4, Managing printers and print jobs

About content types

About content types

The ``content type'' tells the print service what types of files can be printed on a particular printer type (or interface script). Most printers can print only one type of file. For them, the content type is likely to be identical to the printer type. Some printers, however, can accept several different types of file and print their contents properly. When adding this kind of printer, specify the names of the content types the printer accepts.

When a user submits a file for printing, the print service searches for a printer capable of handling the job. The print service can identify an appropriate printer through either the content type name or the printer type name.

To specify the content types that a printer can accept: 

  1. In the Printer Manager, select the printer from the list.

  2. Select Advanced from the Settings menu, then select Content Types.

If several different types of printer accept the same content type, use the same content type names when you add those printers. This makes it easier for users because they can use the same name to identify the type of file they want to print, regardless of the printing destination.

For example, several manufacturers produce printers that accept PostScript files. Although these printers might require different interface scripts so each can be properly initialized, they all might be capable of printing the same content type, which you might call PostScript. As another example, several manufacturers produce printers that accept ANSI X3.64-defined escape sequences. However, the printers might not support all the ANSI capabilities, or each might support different sets of capabilities. You can specify different content type names for these printers to differentiate them.

The print service recognizes special meanings for these content types:

The most common type of file on the UNIX system is known as simple. The print service assumes this file type contains only printable ASCII characters and the backspace, tab, line feed, form feed, and carriage return control characters. See the lpadmin(ADM) manual page for more information. 

The terminfo content type name does not refer to a particular type of file, but instead refers to all the types represented in the terminfo database. It is not likely that any printer is capable of handling all the types listed in the database, but this name is reserved for describing possible filter capabilities.

The print service reserves the content type name any for describing the types of files a filter can accept or produce. This name should not be used as a content type when adding a printer.

If a printer can handle simple file types, include simple in the list of ``Supported'' content types. If you do not want a printer to accept simple file types, you must include an alternate list of content types that the printer accepts. (If no other content type is appropriate, use the printer interface script.)

If you do not define the types of files a printer can accept, the print service assumes the printer can print only files of content type simple. This may be sufficient if users choose the proper printer and make sure the files are properly prepared for the printer before they are submitted for printing.