There is basically no 232 serial port on the notebook. Therefore, in the lower computer with 232 serial port or self-receiving debugging through serial port, there must be hardware equipment from USB to 232. I bought AVRVI's USB-ISP recorder and installed the driver corresponding to the conversion chip PL2303. Please ask everyone, I am currently learning to program with MFC, and the code I am learning is

//CString sPort；

//exercise. Format (_T("\\\\). \\COM%d ")，3)； //serial port 2

hCom = CreateFile("COM 1 "，GENERIC_READ | GENERIC_WRITE，0，NULL，OPEN_EXISTING，FILE_FLAG_OVERLAPPED，NULL)；

If the USB-to-232 chip uses PL2303 and the corresponding driver is installed, can this original way of operating com port operate USB port?

After that:

I bought a USB-to-serial cable, and the chip is CH340.

Install the driver and display the serial number. But the external device shows USB-SERIAL CH340(COM 1).

For the point attribute, the following common address is Port_#0002. Hub_#0005。

I can't complete the normal data exchange by crossing two lines with 2-3 ports.

1 line, 2-3 ports are short-circuited, and data can be sent and received.