I have been trying to get an EVDO modem to work with Centos 5. I can make it dial out with wvdial only when I'm the root user. Otherwise I get this error:
Cannot open /dev/ttyUSB0: Device or resource busy
I added the user to the uucp group.
crw-rw---- 1 root uucp 188, 0 Dec 3 02:30 /dev/ttyUSB0 crw-rw---- 1 root uucp 188, 1 Dec 3 02:30 /dev/ttyUSB1 crw-rw---- 1 root uucp 188, 2 Dec 3 02:30 /dev/ttyUSB2 crw-rw---- 1 root uucp 188, 3 Dec 3 02:30 /dev/ttyUSB3
What have I missed?
[mailto:centos-bounces@centos.org] On Behalf Of Frank Cox Sent: Wednesday, December 03, 2008 3:50 AM To: centos@centos.org Subject: [CentOS] User access to /dev/ttyUSB0
I have been trying to get an EVDO modem to work with Centos 5. I can make it dial out with wvdial only when I'm the root user. Otherwise I get this error:
Cannot open /dev/ttyUSB0: Device or resource busy
I added the user to the uucp group.
crw-rw---- 1 root uucp 188, 0 Dec 3 02:30 /dev/ttyUSB0 crw-rw---- 1 root uucp 188, 1 Dec 3 02:30 /dev/ttyUSB1 crw-rw---- 1 root uucp 188, 2 Dec 3 02:30 /dev/ttyUSB2 crw-rw---- 1 root uucp 188, 3 Dec 3 02:30 /dev/ttyUSB3
What have I missed?
Hmm Lets see here... system-config-network Select (highlight) your PPP Adapter, then click on Edit. That will be under the Devices Tab. Next Look under the General Tab. Place a Check in "Allow all Users to enable or disable the Device".
JohnStanley
On Wed, 03 Dec 2008 07:02:10 -0500 John wrote:
Hmm Lets see here... system-config-network Select (highlight) your PPP Adapter, then click on Edit. That will be under the Devices Tab. Next Look under the General Tab. Place a Check in "Allow all Users to enable or disable the Device".
That selection was already in place.
Interestingly enough, using gnome-ppp as a user the I get the "Cannot open /dev/ttyUSB0: Device or resource busy" error. But using NetworkManager to dial the connection works fine to establish the actual connection. However, there is no visible indication from NM that the connection has been established.
On Fedora 10 (where I had this same modem working the other day) I could just set up the connection using the NM "edit configuration" dialog and when I told it to connect the NM icon turned into a little cell phone tower. With Centos 5 I tell NM to "connect to sasktel using modem" and it does its thing and connects and everything appears to work (ifconfig shows me a ppp0 interface), but the icon remains the ethernet plug with the line across it and the tooltip that I get when I mouse over it says "no network connection". It hangs up when I tell NM to disconnect, so NM appears to provide full control.
So it seems that while NM establishes the connection, it doesn't realize that it has done so. I wonder if there is a way to tell it when the connection exists.
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Frank Cox -
John