/dev/ttyUSB0 and PPP

Thu Feb 23 04:50:42 UTC 2006

> On Tue, 2006-02-21 at 19:49 -0800, Harold Hallikainen wrote:
>> > On Sun, 2006-02-19 at 18:15 -0800, Harold Hallikainen wrote:
>> >> > I'm trying to set up a ppp connection through my cellphone. I'm
>> using
>> >> a
>> >> USB to EIA232 adapter on FC4_64. I can talk to the cellphone (send AT
>> >> commands, dial, etc.) from GtkTerm using /dev/ttyUSB0 when logged in
>> as
>> >> root. As another user, I get permission denied.
>> >> >
>> >> > Desktop/SystemSettings/Network lets me define a modem device on
>> ports
>> >> such
>> >> > as  dev/ttyS0, etc., dev/modem, dev/tty|1, dev/input/ttyACM0,
>> >> dev/ttyM0,
>> >> etc. But, no /dev/ttyUSB0.
>> >> >
>> >> > So... what do I do to set up a ppp connection on my cellphone modem
>> on
>> >> /dev/ttyUSB0?
>> >> >
>> >>
>> >>
>> >> Still working on this... A google search came up with the suggestion
>> >> that
>> >> I add
>> >>
>> >> ln -s /dev/ttyUSB0 /dev/modem
>> >>
>> >> to my /etc/rc.local . I've done that and am still having trouble
>> getting
>> >> ppp to dial out. I'm using the network configure menu
>> >> desktop/SystemSettings/network. At one point, I could see it dial
>> just
>> >> the
>> >> 1 dialing prefix, but not the rest of the number. Currently, it
>> doesn't
>> >> try to dial at all. Instead, I get "cannot connect to network device"
>> >> when
>> >> I try to activate it.
>> >>
>> >> As root, I can talk to the cellphone using gtkterm. As a non-root
>> user,
>> >> I
>> >> get permission denied. Here's a little more info:
>> >>
>> >>
>> >> [root at hhlaptop ~]# ls -l /dev/modem
>> >> lrwxrwxrwx  1 root root 12 Feb 19 18:00 /dev/modem -> /dev/ttyUSB0
>> >> [root at hhlaptop ~]# ls -l /dev/ttyUSB0
>> >> crw-rw----  1 root uucp 188, 0 Feb 19 18:04 /dev/ttyUSB0
>> >> [root at hhlaptop ~]#
>> >>
>> >>
>> >> So... any ideas?
>> >
>> > Well, the first thing is to change the permissions on /dev/ttyUSB0.
>> > You need to edit the /etc/udev/rules.d/50-udev.rules and change the
>> >
>> >     KERNEL=="ttyUSB*", GROUP="uucp", MODE="0660", OPTIONS="last_rule"
>> >
>> > line to read "MODE=0666" to permit world read/write operations, then
>> > unplug the dongle and plug it back in.
>> >
>>
>>
>> THANKS Rick! After this change, gtkTerm can talk to the cellphone on the
>> USB as a non-root user. I then tried the internet connection wizard. It
>> exits with error 8. Here's what shows up in /var/log/messages:
>>
>> Feb 21 19:36:59 hhlaptop ifup-ppp: pppd started for home on /dev/modem
>> at
>> 19200
>> Feb 21 19:36:59 hhlaptop kernel: CSLIP: code copyright 1989 Regents of
>> the
>> University of California
>> Feb 21 19:36:59 hhlaptop kernel: PPP generic driver version 2.4.2
>> Feb 21 19:36:59 hhlaptop pppd[3187]: pppd 2.4.2 started by root, uid 0
>> Feb 21 19:37:00 hhlaptop wvdial[3203]: WvDial: Internet dialer version
>> 1.54.0
>> Feb 21 19:37:00 hhlaptop wvdial[3203]: Initializing modem.
>> Feb 21 19:37:00 hhlaptop wvdial[3203]: Sending: ATZ
>> Feb 21 19:37:05 hhlaptop wvdial[3203]: Sending: ATQ0
>> Feb 21 19:37:05 hhlaptop wvdial[3203]: ATQ0
>> Feb 21 19:37:05 hhlaptop wvdial[3203]: OK
>> Feb 21 19:37:05 hhlaptop wvdial[3203]: Re-Sending: ATZ
>> Feb 21 19:37:05 hhlaptop wvdial[3203]: ATZ
>> Feb 21 19:37:05 hhlaptop wvdial[3203]: OK
>> Feb 21 19:37:11 hhlaptop wvdial[3203]: stdin not read/write and $MODEM
>> not
>> set
>> Feb 21 19:37:11 hhlaptop pppd[3187]: Connect script failed
>> Feb 21 19:37:12 hhlaptop pppd[3187]: Exit.
>>
>>
>> So, it looks like pppd is being passed device/modem, but wvdial is not
>> able to communicate with it. I'm guessing the OK entries are the
>> responses
>> from the cellphone, so it looks like we're talking to it. So, what's the
>> line at 19:37:11 mean?
>
> Have you edited /etc/wvdial.conf?  You have to set the MODEM variable in
> the "Dialer Defaults" section of that file.  Something like:
>
> 	[Dialer Defaults]
> 	Modem = /dev/ttyS0
> 	Baud = 57600
> 	Init = ATZ
> 	Init2 = AT S11=50
> 	Phone = 555-4242
> 	Username = apenwarr
> 	Password = my-password
>
> Full details are in the wvdial(1) and wvdial.conf(5) man pages.

OK... Further note! The config file created by the gui looked reasonable.
I changed the modem from /dev/modem to /dev/ttyUSB0 and tried again. I'm
still getting "error 8" and similar log entries:

Feb 22 20:44:09 hhlaptop ifup-ppp: pppd started for home on /dev/modem at
19200
Feb 22 20:44:09 hhlaptop kernel: CSLIP: code copyright 1989 Regents of the
University of California
Feb 22 20:44:09 hhlaptop kernel: PPP generic driver version 2.4.2
Feb 22 20:44:09 hhlaptop pppd[3215]: pppd 2.4.2 started by root, uid 0
Feb 22 20:44:10 hhlaptop wvdial[3231]: WvDial: Internet dialer version 1.54.0
Feb 22 20:44:10 hhlaptop wvdial[3231]: Initializing modem.
Feb 22 20:44:10 hhlaptop wvdial[3231]: Sending: ATZ
Feb 22 20:44:15 hhlaptop wvdial[3231]: Sending: ATQ0
Feb 22 20:44:15 hhlaptop wvdial[3231]: ATQ0
Feb 22 20:44:15 hhlaptop wvdial[3231]: OK
Feb 22 20:44:15 hhlaptop wvdial[3231]: Re-Sending: ATZ
Feb 22 20:44:15 hhlaptop wvdial[3231]: ATZ
Feb 22 20:44:15 hhlaptop wvdial[3231]: OK
Feb 22 20:44:21 hhlaptop wvdial[3231]: stdin not read/write and $MODEM not
set
Feb 22 20:44:21 hhlaptop pppd[3215]: Connect script failed
Feb 22 20:44:22 hhlaptop pppd[3215]: Exit.

I think the key here is "stdin not read/write and $modem not set." The OK
lines seem to be my modem (cellphone) responding to the AT commands. I did
a Google search on the phrase quoted above, and it appears to be a common
problem. My search has not yet revealed a solution. I'll continue the
search, but would certainly appreciate any ideas!

THANKS!

Harold

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