> I'm trying to track down the cause of some garbage in a response when > using an ELM327 (https://www.elmelectronics.com/ic/elm327/) with a > CH341 serial controller. To follow up on this... Here's the device I am working with: OBD2 Scanner Adapter OBD2 ELM327 USB Cable Car Code Reader Diagnostic Scan Tool v1.5, https://www.amazon.com/gp/product/B0897G6BMZ. It has a controller for interfacing with a vehicle's OBD II, and a CH340 for USB communications. I contacted ELM Electronics Support [1] about the garbage I was seeing. I thought I may have the serial port misconfigured in a subtle way. Support wrote back that they did not make the OBD controller in a v1.5. They make, among others, v1.4b and v2.0 [2]. It appears the OBD chip is a knockoff. I also think I tracked down the vendor for the CH340. It is a company called WCH. It looks like they provide a GPL'd driver for Linux [3] and name the driver ch34x. The driver is a lot different than the one provided by the Linux kernel [4]. What I don't know is, if the WCH serial controller is another knock-off. If it is an ill-performing knock-off, then that may explain the problems using the existing Linux driver. Using the WCH driver probably explains why things work under Windows. The WCH driver may fix the problems I am seeing under Linux. Jeff [1] https://www.elmelectronics.com/ic/elm327/ [2] https://www.elmelectronics.com/wp-content/uploads/2020/05/AT_Command_Table.pdf [3] http://wch-ic.com/downloads/CH341SER_LINUX_ZIP.html [4] https://github.com/torvalds/linux/blob/master/drivers/usb/serial/ch341.c
