A tale of two serial-usb converter cables

What works, and doesn't, for you. Be specific, and please include Puppy version.
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mouldy
Posts: 663
Joined: Wed 04 May 2005, 21:47

A tale of two serial-usb converter cables

#1 Post by mouldy »

Sometime back I bought an el cheapo serial-usb converter cable off ebay, no name of course. Turned out it used the winchiphead (ch341) chipset. I played a bit with it, but it required a kernel patch. Now this patch has been around since like kernel 2.2 era for this chipset but only listing for converter included with the early Palm pilot. Requires further modification to include other converters using this chip. I further couldnt get it to even work in XP with included driver, XP would recognize it, install driver off the mini cd, but couldnt then see anything plugged into converter.

I found out 2.6.24 and newer linux kernel is going to support this chipset and provide driver module out of box so figure no reason to beat my head against wall trying to modify old patches, just wait for Puppy with newer kernel.

So I get another cheapie $5 converter off ebay this time making sure it has the pl2303 chipset. This one auto recognized and for my test, plugged an old serial modem into it, set port to /dev/usb/ttyUSB0 and it works like a champ. Anybody with an old serial modem and upgrading to newer computer with no serial port, this is an easy and cheap way to go. Plus these work with old serial tablets and the like.

I will hold off absolute condemnation of the ch341 chipset converter until I can try it with newer kernel that has built in support, but I recommend anybody buying one of these look for the pl2303 chipset. Though even if it works under new linux kernel, if you want to use the ch341 chipset converter under windows also, be aware even the windows driver may not be totally functional, seems to be hit or miss whether it works.

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mouldy
Posts: 663
Joined: Wed 04 May 2005, 21:47

#2 Post by mouldy »

Okay, I downloaded Puppy4 with 2.6.25 kernel. It has ch341 module. I got my old serial modem connected and working with the winchiphead cable. Yippie.

Puppy4-2.6.25 version is bit funky. To get it to recognize usb mouse or the usb-serial cables, I had to modprobe ohci-hcd, then for the winchiphead cable had to then modprobe ch341 Barry did away with gkdial and his pup connect with wvdial is all thats left. It gave me error with /dev/modem simlink to /dev/usb/ttyUSB0, saying too many simlinks. Guess one is too many??? When I edited /etc/wvdial.conf and gave port directly as /dev/usb/ttyUSB0, it truncated /dev/usb/ttyUSB0 down to /dev/usb and then gave error. I could have used mknod and created /dev/ttyUSB0, but instead just used ROX to drag it from /dev/usb to /dev. Never figured why Puppy had it in subdirectory anyway, no other linux distribution I've used does this. Worked. I suspect all this will be cleaned up in next version of Puppy as Barry said he would only be offering version with 2.6.25 kernel. If nothing else people will want to be able to use usb mice from live cd.

But did I mention the super duper el cheapo winchiphead cable now works under Puppy, but doesnt under my XP install with that horrible factory driver that came with the cable....

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