Milt;
Another issue that commonly trips up people that are new to Linux
(Unix) is file permissions. /dev/ttyS0 is a file. As such it is "owned"
by somebody and access to the file can be restricted. This is a key
feature of the Linux security model and missing from DOS-based Windows
programs (95, 98). Windows NT and 2000 derivatives have something
similar called Access Control Lists (ACL).
There are a variety of ways to see permissions but the command
ls -al <full path filename> is an easy one.
Many distributions limit access too the serial port to owner/group. In
RH 8.0 this is root/uucp.
One easy way (perhaps not the most secure) for kpsk to access the serial
port is open it to "others"
While logged in as root
chmod o+r /dev/ttyS0 adds others read access only
chmod o+w /dev/ttyS0 adds others as write access
after a chmod you can run ls command to see the changes, so if you ever
get the "Permission denied" response this gives some idea what's
happening. There are lot's more details on permissions realted to
keeping your system secure that a good or HOWTO's will help you with.
On Sat, 2002-10-19 at 18:12, Ernest Stracener wrote:
> oops...meant to also send this to the list...here 'tis...
>
> ---------- Forwarded Message ----------
>
> Subject: Re: [Kpsk-users] Sound card with KPSK
> Date: Sat, 19 Oct 2002 16:56:01 -0500
> From: Ernest Stracener <ds3@...>
> To: Milton Cram <mecram@...>
>
> Hi Milt. Welcome to linux! :) :)
>
> The manual addresses the sound card issue & serial port stuff in detail. You
> are correct: the soundcard is not being freed up by KDE when you try to start
> KPSK. KDE starts the soundserver by default & gives it real time priority,
> essentially reserving the use of the soundcard for KDE. Since KPSK runs in
> real-time, it needs full access to the soundcard; the answer is in unchecking
> the "run with realtime priority" box in the soundserver dialog (run 'kcmshell
> arts' from the command line in a terminal window in KDE). KDE will usually
> automatically free up the soundcard after 60 seconds without any events that
> require sound; this can (and should) be changed in the same window as
> above...I set mine at 15 seconds to minimize the wait.
>
> You'll want to turn off any system sounds/notifications, as they may be
> transmitted if they go off while transmitting. Look for "Look n' Feel"
> -->Sounds in your application menu (e.g. from the K button in the lower left
> hand of the screen).
>
> The first serial port is usually /dev/ttyS0. Second would be /dev/ttyS1,
> etc.
>
> I can't boot into Mandrake 9.0 right now, or I would give you better step by
> step instructions. Give this a try and let me know! Glad you are giving
> linux a try & especially glad that you are trying to use KPSK! :)
>
> 73-
> Ernie
> kg9ni
>
> On Saturday 19 October 2002 03:39 pm, Milton Cram wrote:
> > Help,
> >
> > I am new to Linux (two days only!). I have Mandrake Linux v9.0 with KDE3
> > running on a PIII-1GHz. The basic system appears to be running correctly,
> > but when I run KPSK, I get an error message "Unable to open the audio
> > device". When I then click on OK, the dialog box shows "/dev/sound/dsp"
> > for the Audio device, and the entry for PTT device is blank.
> >
> > The Hardware list shows that the sound card is present.
> >
> > Is some other application "locking" the card? I'm not aware of any other
> > applications running that might interfere with the use of the soundcard.
> >
> > How do I check for software that might be using the soundcard as a
> > resource?
> >
> > Also, how do I tell KPSK to use the first serial port for PTT? Perhaps
> > this will be obvious when I am able to get beyond the soundcard error
> > message. (At this point, I never get to the KPSK screen.)
> >
> > Thanks for the help.
> >
> > Milt, W8NUE
> >
> >
> >
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