keysonic RF numberpad mode

[squiffy]

just using keysonic rf keyboard with sig pc, for uiojklm keys it is stuck on numberpad mode, have to press FN key to get those letters to type otherwise they come out as 4561230

http://www.keysonic.net/pages/products/keyboards/wireless/ACK_540_RF/ACK_540_RF.html

how do i swith it off