Don't use COM ports, just get an extra LPT port for the system that the printers are connected to. Connect them both up at the same time, create a share for each (say \\printserver\dotmatrix and ...

I have a local laser printer set on port lpt1, and a network plotter on a standard TCP/IP port. The local printer will only work when set on lpt1. Problem is, several times a day it's suddenly on lpt3 ...

We see it all the time, a post based on an Arduino board with multiple comments calling it overkill. How exactly should you control your homemade peripherals if you’re not using a microcontroller (uC) ...