Re: [aclug-L] modem

[Steven Saner <ssaner@xxxxxxxxxxxxx>]

On Mon, 3 Aug 1998, Truong Do wrote:

> Hi,
> There is no /var/log/ppp.log file in my system so I check
> /var/log/messages file.  Here is part of the file:
> 
> Aug  1 19:58:41 localhost pppd[1048]: pppd 2.2.0 started by root, uid 0
> Aug  1 19:58:41 localhost gated[191]: EVENT Delete UpDown lo 127.0.0.1/255 
> <Broadcast Loopback>
> Aug  1 19:58:41 localhost gated[191]: EVENT Add lo 127.0.0.1/255 <Up 
> Broadcast Loopback>
> Aug  1 19:58:41 localhost pppd[1048]: tcgetattr: Input/output error
> [I think the problem is the line above.  Do you think it is the interupt
> number problem?]

I do believe that the above line is indicating the problem. tcgetattr is
the system call that gets information about the serial port from the
serial port driver. The error is indicating that it can not do this. In a
Windows (yukky) environment you would probably receive an error like
"Could't not open serial port" or "Modem not responding." I got this error
when I set the device aurgument to pppd to a serial device that I know
does not exist on my system. 

This could be an interrupt problem, but it could be other things as well.
Here are some things that I would want to know to help troubleshoot.

You use /dev/modem as an argument to the pppd command. /dev/modem is
usually a symbollic link to a device. What is it linking to? Type ls -l
/dev/modem to find out. Is it pointing to the correct device? To use PC
terminology, which COM port is the modem using? Rather than using
/dev/modem for pppd, I would suggest using the driver /dev/ttySx where x
relates to the port as follows:

/dev/ttyS0 - COM 1
/dev/ttyS1 - COM 2
/dev/ttyS2 - COM 3
/dev/ttyS3 - COM 4

Do you get the same errors with this approach?

Next, does the modem work with other dialout software, such as minicom, or
with some other operating system?

What kind of modem is it? Is it internal or external? Do I understand
correctly that this modem did work at some point?

Lots of questions, but their answers might help in diagnosing the problem.

==================================================================
Steven Saner                            SouthWind Internet Access, Inc.
ssaner@xxxxxxxxxxxxx                    Technical Support
http://www2.southwind.net/~ssaner       support@xxxxxxxxxxxxx
                                        http://www.southwind.net
                                        263-7963 Wichita  (800)525-7963


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