coolterm shows just dots

[alfonso]

hello,

I have a Prolific PL2303 USB to Serial adapter.

It works just fine in Ubuntu with minicom but I couldn't make it work with Coolterm on my Mac Book 10.8.2 using the driver found here: http://plugable.com/drivers/prolific/.

When I set the serial I only see a few dots on the screen when I press enter, but not the prompt of the machine to which I'd like to connect.

To be honest I don't know if it's cool term or the driver, but I would appreciate any suggestions.

regards,
alfonso

[roger]

Hi,

all dots shown in the Plain text view of CoolTerm usually means that it can't display the characters it received, i.e. they are un-printable characters with ASCII codes greater than 127 or less than 30. You can switch to Hex view to see the actual codes for these characters. If you expect something readable instead, then it may be that case that the baudrate and/or bit settings are incorrect (which is the most common issue). I would double-check that first.

I have had an issue with a Prolific device in the past where the driver from the prolific website didn't quite work. The only thing I was able to get to work was the driver provided by the manufacturer of the serial port adapter. However, in my case the device was not properly recognized without the correct driver. I.e. I never got as far as being able to connect and receive data.

In any case, you might want to download the driver from the official Prolific website:
http://prolificusa.com/pl-2303hx-drivers/

I hope this helps.

Roger

[alfonso]

Thank you,

I will try that.

Any advice on how on uninstall a previous driver to install the one you suggested? Can I simply install it on top or should I do some manual removal first?

Thanks,
alfonso

[roger]

I just installed the new one and everything worked, even other ports that worked with the original Prolific driver. My guess is that the 3rd party driver installed something else which didn't interfere with Prolific's driver. Your case may be different. Prolific's installer may unstall previous versions of their own driver properly before installing the new one, but I'm not sure.

In any case, to remove the driver, Prolific recommends doing this:

1. Open "Applications-> Utilities-> Terminal"
2. Login to root user and type "su" and enter password.
3. Type "cd /System/Library/Extensions" to go to the "Extensions" folder.
4. Unload the driver (if it had been loaded) by typing "kextunload PL2303.kext" or "kextunload
ProlificUsbSerial.kext".
5. Remove the driver by typing "rm -r PL2303.kext" or "rm -r ProlificUsbSerial.kext". )

[alfonso]

Hi,

I follow the instruction to uninstall but since I had a different driver my kext was different:

Code: Select all

sudo bash
rm -r osx-pl2303.kext/

I kept an eye on the syslog: tail -f /var/log/system.log and I saw this when I connected the usb to serial:

Code: Select all

Oct 31 00:23:20 --- last message repeated 2 times ---
Oct 31 00:23:20 unknown-7c-d1-c3-e1-c3-2d kernel[0]: PL-2303/X V1.3.0 start, Prolific
Oct 31 00:23:20 unknown-7c-d1-c3-e1-c3-2d.home com.apple.SecurityServer[15]: Succeeded authorizing right 'system.print.admin' by client '/System/Library/Printers/Libraries/makequeuesagent' [459] for authorization created by '/System/Library/Printers/Libraries/makequeuesagent' [459] (0,0)
Oct 31 00:23:21 unknown-7c-d1-c3-e1-c3-2d.home PrintUITool[464]: There are no drivers posted for Prolific Technology Inc. IEEE-1284 Controller.
Oct 31 00:23:21 unknown-7c-d1-c3-e1-c3-2d.home mdworker[458]: Unable to talk to lsboxd
Oct 31 00:23:21 unknown-7c-d1-c3-e1-c3-2d.home sandboxd[466] ([458]): mdworker(458) deny mach-lookup com.apple.ls.boxd
Oct 31 00:23:21 unknown-7c-d1-c3-e1-c3-2d kernel[0]: Sandbox: sandboxd(466) deny mach-lookup com.apple.coresymbolicationd

I don't know enough about osx to really understand what's going on.

When I run coolterm I have again the same behaviour: just a lot of dots. When the system I want to connect to is booting I see a lot of dots and I can switch to hex but it doesn't really help...

any idea is appreciated...

thanks,

[roger]

I'm afraid I don't know much about the innner workings of OSX either

What are the names that CoolTerm shows in the list of available ports when you click on the popup menu in the connection settings? Is there more than one for the Prolific adapter? Also, if you select your port, what does it show when you click the button to the right of the popup menu? What are the names of the input and output drivers?

Do you have another adapter that is not Prolific based that you could try?