Ignore Hardware Serial Number

     当电脑上连接相同型号的不同终端设备的时候，每换一台设备，电脑都要安装一次驱动，因为系统把vid pid HWSerNum一起用来定义一个端口。很多设备的HWSerNum跟他的电子序号有关系，如IMEI等。

     这种情况就会影响到工作效率，以下就是一种解决办法。

http://www.ftdichip.com/Support/Knowledgebase/index.html?ignorehardwareserialnumber.htm
If devices have the same vendor ID and product ID but different serial numbers, the system will normally treat them as different devices. This causes the drivers to be installed for each device and create registry entries for each device. 

It is possible to override this behaviour to make the system ignore a device's serial number and treat all devices with matching VID and PID connected to the same USB port as if they were the same device. This is achieved by adding a REG_BINARY value called IgnoreHWSerNum to the registry and setting it to 01. 

     这是一个注册表模板，可根据这个模板来修改。

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\UsbFlags]
"IgnoreHWSerNum05c69025"=hex:01