Questions about the dongle
Because my laptop can't use the parallel port dongle, so I bought a USB to parallel port cable, and then put my parallel port dongle into the adapter line. As a result, it can't be used. The dongle and the adapter line are OK. What's the reason? Isn't it a dongle? No
The reason is very simple. The operation of the parallel port dog is: create file (LPT), while the operation of the USB port dog is to enumerate all the dogs with the corresponding guids on the USB port, and then open the corresponding handles. So, if the software itself has been specified to access the dog through LPT port during development, of course, it can't find the USB port, it's just a visual LPT.
There is a premise to solve this problem. If the software itself supports USB dog (that is, the SDK of USB dog is compiled at the time of compilation), then you can try to copy the data in the parallel dog (generally the system area and user area) completely to the same type of dog with USB interface. If the software itself does not support USB dog, It depends on whether I can get your 20 points by typing so many words, hehe