Author Topic: HOWTO serial port modem - VL5.8 [FINISHED]  (Read 7853 times)


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HOWTO serial port modem - VL5.8 [FINISHED]
« on: July 16, 2007, 07:31:38 pm »
I have now installed and configured  several dial up connections using an external serial port modem, wvdial and VL5.8 GOLD with predictable results each time and I will consider this project complete. Any further  observations and/or suggestions  are welcome.  8)

Modem How To:

This basic howto applies to setting up a serial port modem for those users who do not have access to broadband and wish to use a dial-up connection to access the internet. This particular example was based on my experiences installing and configuring wvdial on a Compaq Celeron 567mhz w/128mb RAM running VectorLinux v5.8 using an Actiontec 560LKA external serial port (esp) modem  and has also been tested with a Diamond SupraExpress esp modem. Obviously, access to a phone line and  an ISP provider are also required for this all to work.

This is NOT a modem howto as that is an extremely complex undertaking. The wvdial homepage is located here:

A brief description of serial ports can be found here:

For an excellent Linux based serial port modems  howto please check here:

Although not specifically a Linux site there is a lot of great information about modems in general here:

For new dial up users, here are several  anecdotal observations:

There are numerous possibilities for dial-up internet connections including external, internal  and USB modems. For dial up solutions it has been my experience that a hardware-based external serial port (esp) modem, rather than a software based modem  (sometimes referred to as a winmodem),  is generally the path of least resistance because it practically eliminates the need for downloading a software tool called "scanmodem"  to determine the chipset of a modem and then  searching for and installing drivers.  Most AMR, CNR, PCI and USB modems tend to be softmodems, and even though some PCI modems are hardware based,  they may require drivers. Tremendous advances have been made in the availability of Linux drivers for softmodems, however,  you must be prepared for the possibility that identifying the modem chipset, then locating and installing  drivers will be a time consuming prospect.

The following is an example of what the dial up modem user faces when using a "softmodem".  You must download and install the scanModem tool, then send an output file to the linmodems support site, then have someone help you determine how to interpret the file, then search for drivers.

After you have located the drivers, this is required:

As you can see, this process is not for the faint of heart! An external serial port modem eliminates all of this.
For those brave souls looking for an adventure,  more detailed information about "winmodems"  and other  softmodems can be found here:

Another point to consider about esp modems is that due to upgrades to broadband, there seems to be an increased availability of discarded esp modems at thrift shops or on ebay and  they can be had for as little as $5 US.

A final note regarding Internet service providers - Some seem to be Linux friendly and some do not. This means that some ISP servers require a special authentication script for login. You should research this and try to avoid these providers. There is a VERY LARGE well known ISP provider that may still require a special authentication script that was supposed to be handled by a dialer called penggy but I have never heard of anyone having success with it. I believe Linspire was granted access to this ISP but don't know if it's available to anyone else. Many ISPs will mistakenly claim not to support Linux when in fact what they mean is,  they do not provide tech support but their servers ARE Linux friendly in that they do NOT require this special authentication script, merely a login name and password. It's best to speak to an engineer, not the customer service reps.

Well, on to the task.....

VectorLinux versions 5.1 and 5.8 appear to ship with ppp (point to point protocol) dialers xisp and chestnut respectively, but  I decided to pursue wvdialer. The wvdialer application is a dialer for use with Unix/Linux and although it does not seem to be included in the packages of either release CD, it is available in the VL repositories located here:

wvdial and qtwvdialer (a frontend GUI for wvdial) are located here:

and wvdial wants wvstreams, located here: ->

Obviously, your PC may not yet have a net connection so you will have to download the necessary files and transfer them to the PC upon which you wish to install wvdial. I transferred these files to the Desktop and installed them in the following order, since  wvdial wants wvstreams first, so: wvstreams, then wvdial, and finally qtwvdialer. These packages were all installed with a simple right click which opens the context menu and then by selecting "install software". Take note that  wvdial and qtwvdialer were both installed into /usr/bin by default. We'll be changing permissions here in a moment to allow users to access these applications.

After installation you will find qtwvdialer in the menu under Network. Upon opening qtwvdialer for the first time, you may be presented with a warning or error notice that wvdial.conf cannot be accessed. This is almost certainly a permissions issue which can be remedied by giving wvdial permissions as root in a terminal:

chmod u+s /usr/bin/wvdial
chmod u+s /usr/bin/qtwvdialer

While we're at it, lets give the wvdial.conf permissions as well with:

chmod u+s /etc/wvdial.conf

Linux permissions explanations can be found here:

The /etc/wvdial.conf file contains information about your modem, account name, login and password and should now be accessible to the qtwvdialer. Once you have opened qtwvdialer, you will be presented with the connect screen including a config button. Selecting this button opens a configuration screen which should open to the modems tab. Select the "run wvdialconf" option and this application will attempt to scan your ports for a modem. It is here that the information from your modem is detected and populated into the wvdial.conf file (located in /etc).

In most cases, selecting "run wvdialconf" on the modems tab will return a series of scans indicating the modem has been detected. If there are any problems in locating your serial port or  the modem, wvdial.conf will NOT be written to /etc. If wvdialconf does not locate your modem, recheck your permissions or run the following command as root from a terminal to force the configuration of your esp modem which is usually located in the COM1 port known as /dev/ttyS0.

setserial /dev/ttyS0

This command should return something like this -> /dev/ttyS0 UART; 16550A, PORT: 0x03f8, IRQ:4

Also check to see if the serial port is activated at boot by checking under VASM > SERVICE > HWSET.

Back to qtwvdialer. Selecting the account tab will present the opportunity to add an ISP account, usually requiring only the phone number of the ISP, your account login and the password you have selected. This information will be given to you when you sign up with your ISP. The other fields are optional references. On this same account page you will find a "more" button which opens a box with a number of fields. These are basically modem instructions and there are usually only several fields that need to be set or altered by the user. The  modem device field default for wvdial is  /dev/modem. Apparently this entry is linked symbolically to /dev/ttyS0.  I have set this field to /dev/ttyS0 with no problems. The other fields that seem to be populated are the init1 which is usually "ATZ", the init2 field and the default BAUD rate which I set to 57000 so as not to choke the wvdial-modem connection. The modem name and type fields are optional for reference. The dial command field was blank but wvdial default is "ATDT" .  I did not alter any of the  other fields in this dialog page and if you decide to do so, it is best to refer to the websites given above.

I did not alter anything on the qtwvdialer tab except to check the "start program after connect" and entered /usr/bin/mozilla to autolaunch the mozilla browser. Once this is all configured you should be able to exit the configuration tab, return to the connection window,  hit the connect button and see and hear the modem dial out and begin the familiar handshake squeal we are all familiar with.

One  or two notes about  anomalous behavior.  For some reason when disconnecting, I have to "hit" the disconnect button twice to kill the connection. Also, for some reason, ticking the autolaunch checkbox on the qtwvdialer tab seems to be disrupting or breaking some of the links to firefox, opera and seamonkey browsers. This may be related to browsers not closing properly when logging off. For example, if I close a browser PRIOR to closing wvdial, then I must reboot to start a new instance of that browser as there is a message indicating that the browser is still running. If I close the qtwvdialer application FIRST, then close the browser... all is well.

All in all however, this procedure has worked well and while cautious tinkering with alternate init strings can help increase throughput speeds, it's been my experience that the "ATZ" in the init1 string field has been sufficient in most cases to get the best performance out of your modem. You should now have a usable internet connection via dialup.  Hope this helps.     ;)

« Last Edit: October 01, 2007, 09:20:31 pm by Trio3b »


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Re: modem how to VL5.8
« Reply #1 on: July 17, 2007, 05:59:00 am »
Not a dial up user.  But a excellent read all the same.  Nice job!