TrueType software is shipped with the StyleWriter because it can image fonts at any resolution with excellent quality, much like PostScript. The TrueType software is intended for users of System versions 6.0.7 up to, but not including, System 7. System 7 includes support for TrueType.
You can use PostScript images and fonts with the StyleWriter, but just as with
the ImageWriter, you'll have to have something that images them in memory
before sending them to the printer (in other words, a Macintosh-resident
PostScript interpreter), or use ATM for Type 1 fonts on a StyleWriter.