Different devices have different ways of reacting when connecting the bcusb , but normally if you do not have the ISP pin connected to VCC the modem should still boot as normal , if it does not , unplug the usb from bcusb to verify that it is not the programmer causing this. If the device still does not boot normally after unplugging bcusb there is a possable bridge somewhere.
With having ISP connected , one of two things could happen once you connect the power , either you will have no LED's on or all may be on. As i do not have this device i cannot tell you exactly what sequence it could be.