AX = 1C BX = rate code = 0 no interrupts = 1 30 interrupts per second = 2 50 interrupts per second = 3 100 interrupts per second = 4 200 interrupts per second - work with the InPort mouse only - sets the rate the mouse status is polled by the mouse driver - faster rates provide better resolution but take away CPU time - values in BX > 4 can cause unpredicatable results