Re: Dial-up modem 'No CARRIER'
Frank Otto said...
> (second try to post this)
>
> marc wrote:
> :
> :> > The laptop modem is dialing and exchanging with the ISP. Then, 24 times
> :> > out of 25, all I get is 'NO CARRIER'. Very occasionally, I connect
> :> >
> :> > I'm on 2.3.13 etch.
>
> I guess you mean 2.6.13... kernel version is quite important,
> see below.
Oops! Yes, 2.6.13
> : Sorry, I posted before disappearing for the night, and realised I should
> : have provided more info.
> :
> : The modem is:
> :
> : 0000:00:1e.3 Modem: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6
> : Family) AC'97Modem Controller (rev 04) (prog-if 00 [Generic])
> : Subsystem: Acer Incorporated [ALI]: Unknown device 007a
>
> Ok, Intel AC97 modem. I guess you are using the snd-intel-8x0m kernel
> module (or whatever it's called, I don't have access to my laptop ATM).
Yes, it loads snd_intel8x0m
> : I'm using sl-modem-daemon. My location is the UK, which is what I have
> : selected in the sl-modem-daemon configuration.
>
> I assume you use the ALSA method of the sl-modem-daemon.
I installed the package, but the only option was country selection.
The brief readme is rather unclear, but I think that the package
defaults to ALSA. Since I haven't done anything else with it, I presume
that's what it's using.
As I mentioned, I have managed to connect - twice in a few hundred
attempts - so it works of a fashion, albeit a useless one.
> In this case,
> the reason for your failures might be that the modem is not "off the
> hook".
> See, the kernel/ALSA developers decided
Uh oh...
> to add an additional
> "off-hook" mixer control to the modem driver. This appeared in kernel
> 2.6.12. By default, this mixer control is muted which means that the
> modem will just not work. You first have to take the modem "off the
> hook", e.g. by running
>
> alsamixer -D hw:1
At first I thought that was a very silly idea, but from what you say, it
looks like "off hook " was added to fix a problem with modems that don't
automatically activate the line - perhaps only in some countries.
My modem "off hooks" quite happily when I ATDT
BTW, I see that ALSA devices can be found by:
# cat /proc/asound/cards
The numbers at the left hand side are the card numbers so you can get to
the modem "soundcard" via:
# alsamixer -c 1
(the regular soundcard being 0)
> If this shows an "off-hook" control
Yes, it does.
> press "M" to unmute the control and exit alsamixer.
> Afterwards, your modem should be able to connect.
The modem has always been able to dial, and the ISP answers, it's after
that that things go pear shaped.
In any case, what I found with "off hook" is that it does exactly that -
it activates the line and so removes the dial tone. Thus, when I try to
pon, the script fails due to the lack of dial tone.
In fact, if I leave alsamixer open, and let the modem dial normally -
starting with "off hook" muted - I can watch "off hook" unmute as the
modem activates the line, them mute again when it fails to connect.
While that's precisely what I'd expect to see, I was surprised to see
alsamixer do this.
> At least this solution worked for me on an IBM ThinkPad R32 (2658BQG).
> If you want to automate this, you can put a call to amixer into your
> dial-scripts, or into the slmodem-startup-scripts... but I forgot the
> exact syntax. Might be "amixer -D hw:1 sset Off-hook unmute".
I'd certainly like to know why the driver doesn't produce any sound -
now that I through the modem's speaker.
Thanks for the info, Frank. That's certainly uncovered a whole new bunch
of stuff that I didn't know existed. Why they have made it so obscure is
another question!
--
Best,
Marc
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