Thank you very much Tweakie.
What controller would you recommend? I would prefer to use USB or Ethernet output.
As TPS has mentioned Ethernet connection seems to be the favourite amongst users.
It is not really possible for me to recommend a particular motion controller as all that I have tried (and I now have 5 different motion controllers) each have their own strong and weak points and it really all depends on intended usage as to which may be best.
A popular motion controller which has excellent manufacturer's support together with a very active user's forum is the Ethernet Smooth Stepper (ESS) from Warp9 but there are others equally appointed. Avoid the Chinese controllers and choose one made in the USA or EU to be sure of manufacturer's full support.
Tweakie.