View Full Version : PCI Modem

Woody Ochs
09-15-2005, 04:53 AM
How does one discover the filesystem identity which Versions 4.0, 3.9, etc. attach to an internal, PCI dial-up modem?
Is it "/dev/ttyS4" or "/dev/ttyS14" or "tts/14" or what? I have a fully-functional hardware modem which works fine on Version 3.6 but which none of the later versions can identify for an effective "/dev/modem" link. "lspci" lists the modem and its interrupt request number (IRQ 10), but not its serial port identity, and "dmesg" doesn't seem to list the device at all.

09-15-2005, 05:03 AM
Maybe this can help http://www.math.sunysb.edu/~comech/tools/PCImodems.html (or this http://linmodems.technion.ac.il/ )

This is from another forum:

"Alternatively, try ls -l /dev/modem to find out the com port. You can also do things like ls -l /dev/ttyS2, etc. All from Command line. The latter gives the c 4 68 part of it. Also see man pages on ls. Watch the spaces in the code.

Two other handy pieces of code, from cmnd line as su:

mknod /devttyS2 c 4 68 Here S2 is COM3, etc.
(this sets S2)

ln -s /dev/ttyS2 /dev/modem Links e.g. S2 to /dev/modem"

Harry Kuhman
09-15-2005, 05:07 AM
PCI modem really isn't meaningful information. Some PCI modems do indeed have a serial interface built in and work as an external modem would, with the normal AT command set. These are well supported by Linux. But many PCI modems are winmodems, modems that don't have a serial interface or respond to the AT command set, but rather are software controled A/D and D/A converters that need complex software drivers to behave like modems. The makers of these cards usually only produce windows drivers for them and call them winmodems on the package (although there are a few internal software modems that there are now Linux drivers for). It would be best i you could post as much information as you can about the make and model of the modem. Also post evertyjing that you can learn about the modem by looing at it in the Windows control pannel (under Device manager in the System section as well as uner the modems icon).

09-15-2005, 05:11 AM
I have a fully-functional hardware modem which works fine on Version 3.6... this is very strange and can be sign that this modem is a realy hardware one, but - who knows...

Woody Ochs
09-20-2005, 05:38 AM
Thank you for your replies, but the modem in question is not a winmodem or a linmodem; it is, as I mentioned, a fully-functional, hardware modem. The system recognizes it on the PCI bus through I/O e400 and irq 10 at the serial port which the Dirty Operating System (excuse me: "Disk Operating System") would call "comm 5", which Linux 2.4 called "/dev/ttyS4", and which Linux 2.6 calls "/dev/ttyS14". What does UNIONFS call this port? For that matter, how does one identify an operational serial port on any Linux system? This is the problem which underlies a great number of the "modem questions" submitted to various internet fora. Once the "mystery port" is identified then a simple link can connect the generic file, "/dev/modem", from the dialer-program to the system's serial port file. It's a question whose answer should be as simple as "1,2,3" (or "0,1,2" or "1,10,11"), but in the Unix world that evidently is not the case.

09-20-2005, 04:54 PM
Did you try ls -l /dev/modem? I have winmodem and this command give mi this output:
kurumin@kurumin:~$ ls -l /dev/modem
lrwxrwxrwx 1 root root 11 2005-09-20 16:13 /dev/modem -> /dev/ttyLT0

I think, this make sense. My first answer is from some discusion about USR 5610 internal PCI HARDWARE modem.

I am at the moment in Kurumin distro, but it is based on Knoppix&Kanotix.

Woody Ochs
11-28-2005, 02:44 AM
On this matter of Knoppix 4.0 not being able to open an internal, PCI dial-up modem there seems to be no resolution. I have used "mknod" and "MAKEDEV" to generate a character file "/dev/ttyS14" with full permissions for everyone and soft-linked "/dev/modem" to it, and still the modem dialer reports that it is unable to open that modem. This is, as I mentioned earlier, no sort of Winmodem or Linmodem or Sinmodem; it is a fully functional hardware modem which works fine with Knoppix 3.6 and should work with the 4.0.2 CD but doesn't. Does anyone know where some information might be available?

01-08-2006, 12:56 AM
I am having what might be exactly the same problem as you!

I have that same US Robotics 56k PCI internal hardware modem!
Right now I am running it under Knoppix 3.7 (where it works ok), and here's where that modem was found by Knoppix:
The entry in "dmesg" is as follows:

PCI: Found IRQ 10 for device 00:09.0
Redundant entry in serial pci_table. Please send the output of
lspci -vv, this message (12b9,1008,12b9,00d7)
and the manufacturer and name of serial board or modem board
to serial-pci-info@lists.sourceforge.net.
ttyS04 at port 0xe800 (irq = 10) is a 16550A
And running the "lspci -vv" command gives (for this modem):

0000:00:09.0 Serial controller: 5610 56K FaxModem 56K FaxModem Model 5610 (rev 01) (prog-if 02 [16550])
Subsystem: 5610 56K FaxModem: Unknown device 00d7
Control: I/O+ Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR+
Interrupt: pin A routed to IRQ 10
Region 0: I/O ports at e800 [size=8]
Capabilities: [dc] Power Management version 2
Flags: PMEClk- DSI- D1- D2+ AuxCurrent=0mA PME(D0+,D1-,D2+,D3hot+,D3cold-)
Status: D0 PME-Enable- DSel=0 DScale=2 PME-(And I have /dev/ttyS4 linked to /dev/modem as well... though that isn't absolutely necessary if you set your kppp dialer to use /dev/ttyS4 instead.)

From these, you can clearly see that it's been identified as and/or set to:
/dev/ttyS4, IRQ 10, port 0xe800 and was recognized as a working modem in the diagnostics I ran as well under the modem dialer! Remember, just because that program sees a 16550 UART doesn't mean it's really a modem at that port... could just be a simply serial COM port controller.

HOWEVER, WHEN I MOVE THIS HARDWARE MODEM TO ANOTHER BOX (Knoppix 4.0.2 won't recognize the 'bus mouse' on this one!) AND TRY to connect to the Net with it, Knoppix can't find or recognize it!!! And I have even less hardware on the box than this one! That one uses PS/2 mouse&keyboard, but does have a PCI128 sound card. The data I get from "dmesg" has absolutely nothing about the modem, but using the "lspci -vv" command does give something similar to what we have above. It was either IRQ 11 or 10 and the port was 0xe400.

(REVISED): At first, I was going to agree with the thread poster: That under kernel 2.6.x, Knoppix has a problem with these modems, but (see below) after finding they do work on an HDD installation, I'm guessing there's something wrong with how the newer Knoppix versions try to identify hardware!!! Why else would it work on an HDD, but not under the "LiveCD" ???


The Starman (use http://thestarman.dan123.com/FF.html to write me).

01-08-2006, 12:51 PM
In case someone still needs help with this... I just finished installing Knoppix 4.0.2 onto a small 'test drive' to see what would happen, and... and here I am writing this using my USR 56k PCI modem under Knoppix 4.0.2 !!!

I think I might know what went wrong if "Woody Ochs" actually did try everything he could AFTER installing Knoppix:

First, I noticed a new line in my "dmesg" output:
ttyS10 at I/O 0xe400 (irq = 11) is a 16550A

So, Knoppix 4.0.2 with the Linux kernel 2.6.x will recognize my modem AFTER it's installed on a hard disk! [WHY can't it do so while running from the LiveCD?!] And in this case it was set to: ttyS10 at IRQ 11. HOWEVER, since Knoppix doesn't include that device in its /dev directory, you need to create a listing for it! So, I clicked on Konsole and did an su root followed by this command:
mknod ttyS10 c 4 74which if you perform an ls -l /dev/ttyS10 command, you should then see (with a different date):

crw-r--r-- 1 root root 4, 74 Jan 8 03:22 /dev/ttyS10

But that's not all you need to do! (And maybe this is where Woody went wrong.) You need to change the Group ownership to "dialout" like all the other tty serial devices! So do this command: chgrp dialout ttyS10, and you should then see:

crw-r--r-- 1 root dialout 4, 74 Jan 8 03:22 /dev/ttyS10

after doing another ls -l /dev/ttyS10 command.
From that point on, it was quite easy to use the Knoppix "Modem Dialer" setup software to get online here!!!

BUT, THIS ONLY HELPS IF YOU FIRST DO AN INSTALL OF KNOPPIX ON YOUR HARD DISK... Originally, I posted here because I want to go online with my modem using only the 'LiveCD'. Right now, I'm guessing that just isn't possible under the present boot-up scripts... oh, well.

The Starman