The bottleneck does indeed seem to be on your side, then. Are you doing anything significant in the control's ONCOMM event? If not, make sure SThreshold = 0. What handshaking method are you using (if any)?

>The file size is about 1 meg. The distance is about 40 feet.
>
>I know it can go faster because two cnc machines can move the code between themselves much faster than I can from a PC.