Roy, if you have room in your control box you can add a SmoothStepper or similar card there. A lot of times folks are not wanting to rewire things or just can't suffer the downtime so they want a 'plug-and-play' solution. Take a look at: http://www.soigeneris.com/motion_control_and_i_o_boards-list.aspx . The SSENC1 and SSENC2 were developed to provide an easy and fast upgrade path for an existing machine controller. While I built the first one about 3-4 years ago they have been very popular this year with most larger companies phasing out XP and moving on to Win7-64bit. (The Ethernet version is the most popular now.)

As I mentioned before there are other, similar boards to the SmoothStepper but it is my favorite since I got my hands on the USB version right after they first came out.