Universal Serial Bus (USB) port technology has emerged in response to the proliferation of external peripheral devices (digital cameras, removable drives, etc.), that are increasingly being connected to the latest generation of PCs. USB behaves in a similar fashion to conventional bus ports (i.e., serial, parallel, PS/2), but since it does not require any IRQs, more devices can be attached to the system, and the problem of IRQ conflict is eliminated. ATEN's US401 4 Port USB Manual Switch allows up to four PCs and/or Macs to share the use of a single USB peripheral device (printer, modem, etc.), on a one-at-a-time basis. The active computer is selected by means of an electronic push button switch that cycles among all of the ones that are connected. Connect one of our hubs to the downstream ports to increase the number of devices to share between computers.