CompuServe Messages

Robin: Actually, the 1.5MB board in the LJIIP doesn't have anything to do with it if you're running the laser on a parallel port. It has to do with the difference between the way the computer communicates with the printer on the parallel port vs. the plotter on the serial port. If you've configured your serial cable the way the AutoCAD manual recommends, you are communicating with the plotter using an Xon/Xoff protocol. That effectively means that when the plotter can't receive any more data (because its buffer is full) it sends an Xoff signal to the computer and the computer stops sending until the plotter is ready again and sends an Xon. The DOS COPY command has no way of dealing with this. It just keeps sending data to the port and if the plotter isn't ready, the buffer overflows, the plotter looses track of where it is, and you get stray vectors all over the place. AutoCAD, and the plot spooling programs, deal with proper flow control using the same Xon/Xoff signals. On the parallel port, because there are additional data lines, the computer and the printer communicate. There are additional lines that don't carry actual print data. They simply control the communications flow. Try it with a larger file on the plotter and see what happens. And remember, even if you have a 1MB buffer in your plotter, because plot files are usually 2 or 3 times larger than the drawing file, you can still overflow the buffer even with a 400K drawing. David