GTCO AccuTab II - Users Guide - Manual (Page 46)

AccuTab II 46
 Digitizing Modes
 Controlling the Alarm Using Remote Commands
 Programming Examples
These topics refer to commands that put AccuTab II in a different operating state. The
Remote Commands section contains detailed information about remote commands.
Command emulations for CalComp and Summagraphics digitizers are invoked
automatically when a particular format is selected via the Custom Configuration Card or
the AccuSet Menu selection. However, only AccuTab II commands are referenced in this
section.
Coordinate Formats
Coordinate format refers to the way AccuTab II encodes XY coordinate information before
it sends the data out through a communication interface. The AccuTab II and your
application program must speak the same coordinate “language” for information to be
properly transferred.
You have three basic format choices to make:
 GTCO versus CalComp or Summagraphics emulation
 Binary versus ASCII coordinates
 Coordinate resolution
The topics below describe the formats available and show you how to select them. If you
are developing your own software, these sections will also help you choose a format that
suits your needs.
Binary Formats
Binary formats encode coordinate information compactly. Binary coordinate formats are
shorter than ASCII formats, transmit faster and take up less space if stored. On the other
hand, binary formats cannot be directly displayed on a terminal or printed-they must be
converted first into displayable characters.
Binary formats use the high order bit in each byte as a synchronization bit. The first byte in
each format has its high order bit set to 1. The remaining bytes have their high order bits
set to 0. The application program must examine the high order bit of each byte to
determine when a format begins.