Since computers no longer put parallel ports on computers as a rule I am wondering if I should just go this route? One of the things about my router table is 100ipm is the best I can do and feel good I'll have no issues, loosing steps and so on, would the Smooth Stepper help me gain a little in this area?
Well, personally I think the SmoothStepper is great as it lets the PC do what it is great at (crunching numbers and giving us a nice display) and lets the motion control board so what it is great at (providing a smooth pulse stream). I first bought one last summer for a custom machine that was VERY time critical and I did not want to risk being bogged down with parallel port issues. I had the SS running things in about 15 minutes. (I liked them so much I sell them now.) If you are at the mechanical limits of your drivers/motors and so on then the SmoothStepper won't make it go faster. Some folks have found ,(
http://www.machsupport.com/forum/index.php/topic,11108.0.html ), that it has allowed them to tune the machine better as the pulse stream is smoother.
I think the real test is how much time it will take to get a parallel port working on a particular PC, some just work, some are a bear to get going and some just won't work with Mach. The only issue like this with the SmoothStepper I am aware of is with some older USB 1.1 ports. I have an older HP that the built in ports have always been flaky so I just put in a USB/Firewire PCI card.
One thing you will want when using a SmoothStepper is good optical isolation between the SmoothStepper and your I/O and stepper drivers. Any noise in the system that would cause an intermittent 'wired' issue on a parallel port driven machine will likely be very apparent with a USB motion controller. The noise is there either way but the USB will really let you know. I have always recommended optical isolation either way. Drivers like the new G540 even have it built in.