When ordering the GSM400 please use part number 10613The Global Barcode Scanner Manager 400 organizes serial port barcode scanners with plug and play simplicity. GSM400 Global Barcode Scanner Manager 400The GSM400 has four (4) numbered serial ports on the side. Plug a scanner in and that scanner is assigned to the corresponding numbered interface on the Global 400mp. Plugging in and unplugging additional scanners as no impact on scanners already plugged in and assigned to an interface. Those scanners remain paired with that interface until you change them. Fast, simple, reliable. Your time is valuable. You'd rather be producing a product than trying to figure out a device that is supposed to make production easier. GSM400 gets you to work quicker and keeps you working.