NXT.USBFunctions to choose and connect to NXT bricks connected through USB. So far, it works on Linux (users of other platforms, your help is welcome).
val bricks : unit -> device list Lwt.tbricks() returns the list of LEGO NXT bricks on the USB bus.
connect dev connect through USB to the brick device dev (given by Mindstorm_lwt.NXT.USB.bricks). See the section "connectUSB" for more information.