prolific usb to serial dropping characters with linux

[chrisw957]

I'm using fusion 2.0.6 with Ubuntu as the guest. When I try to use a new prolific usb to serial adapter, it discovers ok, and if I launch minicom, I can send a receive small numbers of characters ok, but if the device I'm talking to sends more than a few characters, then it drops characters. This is at 115200kbps. I tried a keyspan usb to serial adapter and it does the same thing. There doesn't appear to be anything in the linux log that is related to this.

I installed the trial of parallels, and imported the ubuntu vm and it works fine with the prolific serial adapter, so I know the hardware and OSX side are ok.

Any solutions for this problem?

Thanks.

[chrisw957]

Just as a followup, I downloaded the Fusion 3.0 trial, and now it discovers the prolific adapter, and assigns it to ttyUSB0, but when I run minicom, I get an error that it can't open the device, or it doesn't exist.

I guess I will just pay the "upgrade fee" to upgrade my fusion 2.0 license to parallels desktop.

I must say I'm a little disappointed though.

-chris

[woodmeister]

I had similar issues with various versions of Fedora. I have 2 Prolific

based serial dongles that I had used. Had these issues even in Fusion 2.X.

In some cases, the Prolific device that was several years old would

work at a full 115K with an older Fedora and the newer Prolific device

would max out at 38K before dropping characters. In a newer Fedora,

the newer Prolific device would not work at all and the older one would

max out @19.2K. Also, in the different versions of Fedora, minicom

would work but other terminal programs wouldn't and visa versa.

Even tried reloading drivers to no effect.

I had a similar issue even on a real PC although not as severe. There

must be some weird thing going on with linux drivers and these parts

which get amplified when using a Fusion VM.

Never did find a solution to the issue.

As a side note, both Prolific parts I have work flawlessly and at max speeds

in Win2k and XP VM's in Fusion. So there must be a linux/Fusion interface

issue that seems at fault. Whether it was a Fusion or linux issue or a little

of both was never determined.