PMDF System Manager's Guide

Two PMDF-FAX channels are used to compose a FAX message: the TEXT_TO_PS channel which translates plain text messages to PostScript and the PS_TO_G3 channel which interprets PostScript input producing as output bitmaps suitable for transmitting to remote FAX devices. Plain text messages are directed to the TEXT_TO_PS channel which then sends its output to the PS_TO_G3 channel. PostScript files may, however, be sent directly to the PS_TO_G3 channel. (Users' ability to do this may be controlled by the site manager.) The output of the PS_TO_G3 channel is then sent to the G3_TO_FAX channel for FAX delivery (i.e., transmission to a remote FAX device).

The conversion channel may be used to convert input formats other than text or PostScript to text or PostScript; see Section 37.2.2.

Note that message body parts beginning with the two characters "%!" or labelled as application/PostScript with a Content-Type: header line will be passed by the TEXT_TO_PS channel, without conversion, to the PS_TO_G3 channel. This allows all messages, PostScript or text, to be sent to a single address (e.g., @text-fax) without worrying about the distinctions between the TEXT_TO_PS and PS_TO_G3 channels.

PMDF-FAX has no control over the contents of PostScript files sent directly to the PS_TO_G3 channel by users. It is possible that such files may generate output (e.g., error or warning messages generated by the PostScript interpreter, output generated by use of the PostScript print operator, etc.). Output produced by the interpreter while processing a message body is mailed back to the message originator along with an explanatory note. (Note that output generated while processing a cover page is discarded.)