Here's something I've needed for a long time - a dual USB to UART converter, i.e. one USB connector and two serial ports on the output, and this together with the DTR/RTS flow control signals brought out, which can be used, for example, to reset and control the bootloader mode of external devices. The whole thing can be bought for about a dozen zloty, the price depends on the quantity imported and the online shop chosen.
Like the well-known CH340, this chip gives us a choice between 3.3 V and 5 V logic levels. Also in an analogous way, it has one rather serious shortcoming, namely that it cannot provide a sufficiently large current from its 3.3 V pins for many applications, so if we want to run some Wi-Fi modules with it such as the ESP8266, ESP32 or there BK7231, we need to arm ourselves with an external chip with a 3.3 V LDO, such as the AMS1117-3.3 for example.
The CH342 itself is available in tiny housings such as QFN24 (CH342F) and ESSOP-10 (CH342K). The CH342 requires minimal external components to operate.
The main motivation and 'battle test' for this module was to use it to work with
BK7231 , as this chip has two UART ports that are both actively used during firmware development - one is used to display the device activity log and the other for programming. Here are the pictures from colleague @DeDaMrAz :
Unfortunately, however, it was not possible to make the absolute minimum connection, as the Beken would not start without an external 3.3 V supply:
Looks like we're in for an additional 3.3 V LDO hand-soldering to the underside of the board shown. How about finding a module with CH342 and AMS1117-3.3? That would be the best option.
In any case, the UART works fine - the computer immediately sees the COM ports, here for example COM4 and COM7 and we can operate them via Realterm:
In summary , I liked the CH342-based USB-2TTL module very much. Its only downside is the lack of a good LDO on board, which complicates things in some tasks and, for example, makes it difficult to connect the whole thing to a programmable Wi-Fi module. On the other hand, I consider the presence of DTR and RTS lines to be a plus - many cheaper adapters lack this.
Finally, it is worth mentioning that the module is equipped with a modern USB C-type connector, so there is no problem with the orientation of the plug.
Have you used the CH342? What applications do you see for this chip? 
Comments
Do you have the possibility to check the operation on some Linux ? My CH341 often had problems working when connected to faster usb ports. Connecting via a hub at a lower speed helped. [Read more]
I like it! Seemingly a trivial idea but in many cases using 2 UART two converters are less convenient than a single one. @gulson maybe there is a chance for such dual converters with CH342 to appear in... [Read more]
Unfortunately I do not have access to them. [Read more]
I have a question. Do we see 2 com ports in the system? E.g. com5 and com6? [Read more]
There are still modules on the CP2105. [Read more]
There is also the FTDI4232 [Read more]
Of the dual ones, there's also the XR21V1412IL32TR-F. I used the single version and it worked well with a wide baudrate range. [Read more]
About this toto. I was just about to write about it - majfriends also have a ready-made one, e.g: https://pl.aliexpress.com/item/1005003624740507.html The chip itself is sitting on my desk, the FE1.1S... [Read more]
Question: does it not stretch the stop bit for speeds above 500 kbaud like CH340 and CH341 (https://github.com/nospam2000/ch341-baudrate-calculation)? [Read more]
I will try to check what you have written about. @ElektroMusician - then there are two COM ports visible, as in the subject content and in the screenshots. I think this LDO from the board is an XC6206. ... [Read more]
I have long since switched to something like this ;) https://github.com/r2axz/bluepill-serial-monster [Read more]
As others have mentioned here there are also 4 channel adapters for the FT4232. I was recently building a reader for my own use and was looking for some usb <-> 4x serial port adapter and bought... [Read more]
Somewhere I flashed some programmer on a CH347 that read/programmed SPI even expressly relative to the well-known CH341. [Read more]
p.kaczmarek2 Thank you very much for your reply. Overall a very cool topic. I have found a lot of helpful posts here regarding what has been bogging down my mind. Although the project has bogged down,... [Read more]