The interface type refers to the way and type of connection between the card reader and the computer host. Currently the card reader are using USB interface, divided into USB1.1 interface and USB2.0 interface, the maximum data transfer rate of the two are different. USB1.1 is 12Mbps, while the USB2.0 is 480Mbps, USB2.0 interface of the maximum data transfer rate of USB1.1 interface is 40 times, with obvious advantages, but the product price is relatively more expensive than the USB1.1 interface products. USB1.1 interface products are relatively more expensive. USB's full name is Universal Serial Bus, up to 127 peripherals can be connected, because USB supports hot plug and play, plug and play advantages, so the USB interface has become the standard interface of the scanner. usb has two specifications, that is, usb1.1 and usb2.0. usb1.1 is the more common usb specification, the high-speed way of its The transmission rate is 12Mbps for the high-speed mode and 1.5Mbps for the low-speed mode. note: b here means Bit, 1MB/s (megabyte per second) = 8MBPS (megabits per second), 12Mbps = 1.5MB/s. Currently, low-end scanners for home use are mainly of the USB interface type. The USB 2.0 specification evolved from the USB 1.1 specification. It has a transfer rate of 480Mbps, which translates to MB of 60MB/s, enough to meet the rate requirements of most peripherals.The Enhanced Host Controller Interface (EHCI) in USB 2.0 defines an architecture compatible with USB 1.1. It can be used with the USB 2.0 interface, which is compatible with USB 1.1, but is not compatible with USB 2.0. It is possible to drive USB 1.1 devices with USB 2.0 drivers. This means that all USB 1.1 enabled devices can be used directly on USB 2.0 ports without having to worry about compatibility issues, and that accessories such as USB cables, plugs, etc. can also be used directly. Now the host with a USB interface, so the USB optical storage application is extremely convenient, as an external optical storage device interface, the application is quite flexible, and do not have to add additional equipment for the interface, reduce investment.