Hi John, PERIOD is only relevant to freqmod - unless you comment it out (by putting a ; in front of it in the ini file), the machine is likely to lock up when using steppermod. Ian -- Ian W. Wright Sheffield UK www.iw63.freeserve.co.uk ----- Original Message ----- From: "John Sheahan" > > So to tune this, > decide which backend (steppermod.o or freqmod.o) you > are using,