[CentOS] finding the right serial port, enabling & configuring it [was: Re: fax software]

Robert Heller heller at deepsoft.com
Tue Mar 29 15:56:17 UTC 2011

At Tue, 29 Mar 2011 11:35:49 -0400 CentOS mailing list <centos at centos.org> wrote:

> On 03/28/2011 04:22 PM Robert Heller wrote:
> > At Mon, 28 Mar 2011 15:53:50 -0400 CentOS mailing list <centos at centos.org> wrote:
> > 
> >> On 03/28/2011 05:59 AM Adam Tauno Williams wrote:
> >>> On Sun, 2011-03-27 at 22:41 -0400, ken wrote:
> >>>> It's been many years, but it seems that I have to receive a fax and
> >>>> might have to send one too.  Is there a way to do this on CentOS 5.5?
> >>>> (Hope so.)
> >>> Hylafax;  has been quietly running at work, without incident, for years.
> >>> <http://www.hylafax.org/content/Main_Page>
> >> Thanks everyone for your suggestions.  I remember both of these packages
> >> from years ago-- the last time I set up a fax.  At that time I bought an
> >> internal modem-- not a Winmodem, one with jumpers on it to set the com
> >> port and I believe the interrupt also.  Now, however, I'm working on a
> >> laptop with a serial chip on the mainboard and it's a different story.
> > 
> > Is this an RS232 port connected to an external modem or is it some sort
> > of internal modem?
> Internal... on a laptop... so a winmodem.  :(
> > 
> >> I've been reading the Serial-HOWTO, but it's a huge doc and I hope I
> >> don't need to read this entire monograph to get the serial port set up
> >> for the modem so that the fax software can use it.
> >>
> >> I've run minicom to see if I can dial out with it-- to test if I have
> >> the modem's serial port enabled and configured properly.  So far, no
> >> joy.  Anyone have tips to set up the modem so that efax or (more likely)
> >> hylafax can use it?
> > 
> > Almost all *internal* modems (esp. on laptops) are Winmodems and are
> > thus pretty close to useless under Linux.  It might be easier / cheaper
> > / less agravating to just go down to Best Buy and buy a Creative
> > Blaster analog RS232 serial modem.  Something like $50US.  Note: most
> > newer laptops don't have an external RS232 connection, so you will need
> > to get a USB=>RS232 adapter, most of which work out-of-the-box under
> > Linux. (Don't get a USB connected analog modem -- most of these are
> > Winmodems or something equally odd.)
> Yeah, I think you're right about the Winmodem.  "setserial -g
> /dev/ttyS*" showed just two recognized serial ports.  Rebooting and
> checking the BIOS told me that the second one was for the IR (InfraRed)
> device.  This laptop does have a regular serial port on it (I insisted
> on it when I was shopping).  I also have a PCMCIA slot and an old modem
> card from a previous laptop, so that might be a better option than
> wrestling with a winmodem.  I don't know yet....

The old PCMCIA modem card might not be a fax modem.  If the laptop does
have a "good old" DB-9 serial port connector, then going to Best Buy
(or CompUSA, etc.) and getting something like a Creative Blaster analog
RS232 serial modem might be also quite easy and painless.

> > 
> > Otherwise, what does:
> > 
> > /bin/setserial -g /dev/ttyS*
> > 
> > display?
> > 
> > (You might need to be root to do this:
> > 
> > sudo /bin/setserial -g /dev/ttyS*
> Did this (see above) and the "serial port" (or whatever) which the modem
> is supposed to be connected to doesn't even show up.  From what I've
> gathered from the Serial-HOWTO, the modem (again, winmodem) is a PnP
> ("plug-n-play")... I'm guessing this thing (from "scanpci -v"):
> pci bus 0x0000 cardnum 0x1f function 0x00: vendor 0x8086 device 0x24cc
>  Intel Corporation 82801DBM (ICH4-M) LPC Interface Bridge
>   STATUS    0x0280  COMMAND 0x010f
>   CLASS     0x06 0x01 0x00  REVISION 0x01
>   BIST      0x00  HEADER 0x80  LATENCY 0x00  CACHE 0x00
>   BYTE_0    0x01  BYTE_1  0x08  BYTE_2  0x00  BYTE_3  0x00
> I've hunted around for a driver for this, got some indication that there
> might be one, but I haven't found it yet.
> > 
> > )
> > 
> > For example my IBM Thinkpad X31 gives this:
> > 
> > gollum.deepsoft.com% sudo /bin/setserial -g /dev/ttyS*
> > /dev/ttyS0, UART: undefined, Port: 0x03f8, IRQ: 4
> > /dev/ttyS1, UART: unknown, Port: 0x02f8, IRQ: 3
> > /dev/ttyS2, UART: unknown, Port: 0x03e8, IRQ: 4
> > /dev/ttyS3, UART: unknown, Port: 0x02e8, IRQ: 3
> > 
> > I think /dev/ttyS0 is the IR port, which I don't use.  The Winmodem does
> > not show up as a /dev/ttyS* port, since it is not really a serial port
> > at all.
> I got exactly the same output.  Rebooting and going into the BIOS, I
> found that my IR card was bound to COM2 (ttyS1) and so moved it to COM4,
> thinking maybe that would uncover the modem's port... but no.
> I've got a couple dozen other things I need to do... and the person who
> was going to fax me something is scanning the doc and attaching it to an
> email, so I don't need the fax anymore.  So I'm bagging this project for
> now.  Down the road, however, I want to set up an answering machine app
> on this same machine, so I'll likely come back to all this.  So in the
> meantime, if anyone has any info on the driver which is going to light
> up this winmodem, give me a little shout.
> Thanks much to everyone who replied... all good tips... much appreciated.
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Robert Heller             -- 978-544-6933 / heller at deepsoft.com
Deepwoods Software        -- http://www.deepsoft.com/
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