You should be ok pending distance of serial connection because noise is a factor and i think its a 15m limit max but at god knows what baud rate and cable. I would be checking over your usb connection, maybe a dodgy hub, dry joint or directeq cable is dodgy. Bluetooth is another option and wifi if distance is needed
I just use a eqdirect usb and haven't had any issues but arn't running over 2.5meters so can't say much.