This may be a novice question, but I'm trying to install OpenWrt on a set of AP3825i access points. I have a USB to console cord, cheap one with a ch340 chip. It is going from a USB port of my computer to the Console port of the 3825. A cat5e cable is going from LAN2 to the router. I'm following the instructions on the install page (I think) but I cannot seem to get PuTTY to connect.
Under the serial options I'm setting:
Serial line to connect to - COM3 (confirmed in device manager)
Speed - 115200
Data bits - 8
Stop bits - 1
Parity - None
Flow control - None
Then I get "Unable to open connection to COM3 Configuring serial port: Error 31: A device attached to the system is not functioning.
Is it a bad cord, other hardware, or am I missing something? I've tried connecting right after powering up the 3825, when different lights are flashing, and letting it sit for a while. I've tried a couple different 3825 units but no luck. After the initial bootup of the 3825 the status lights are:
Status - flashing green
LAN1 - off
LAN2 - solid amber (valid 1gps link)
Radio 2 - flashing green
Radio 1 - solid green (enabled)
According to the manufacturer user guide for the 3825 the flashing status light means it's loading a software program or running a self test. There is no description for the flashing Radio 2 light.
After a while the 3825 seems to reboot, maybe 5-10-ish minutes (didn't time it). I'm assuming it's looking for an manufacturer controller and rebooting by default when it times out on the search.
Thank you so much in advance for any advice on connecting PuTTY to the 3825 units!
This sounds like an issue with your ch340 and/or the drivers. An issue with serial port parameters wouldn't result in this message... you'd simply not see the expected output but the terminal would still open.
If I set the speed different than what's preset in device manager, on 1st connect, it'll throw an error (can't check which, I'm not at home).
If I restart Putty, it'll actually work.
Thank you both for the replies. I ended up fixing it by following the driver. Apparently, it is not uncommon for the cheap cables to have counterfeit ch340 chips in them. Not all, but some. In the Arduino community this comes up on occasion and their resources helped. Newer drivers don't work with the fake chips and cause issues similar to what I was experiencing. Rolling back to an older driver fixes the issue (though may cause others if you need newer drivers for something else).
The cord I purchased has a counterfeit chip (https://www.amazon.ca/dp/B0DG86PM7R). There are a few different pages that give information, but basically you need to block updates to the driver, uninstall the current driver, and then install a c.2019 driver.