Basic setup of a modem in linux
Making a modem work consists of two phases: the modem device must first be made available, and then configured.

  1. # configuring the modem driver:
    1. # a modem found in, e.g., an hp compaw nw8000 laptop computer reports Modem: Intel Corp. 82801DB AC'97 Modem Controller (rev 3) when checking the output of 
      cat /proc/pci
      This modem can be activated with a 2.6.x linux kernel once the sl-modem-daemon package is installed: 
      sudo apt-get install sl-modem-daemon
    2. # an intel modem 82801ca/cam, as can be found in a dell latitude c640:
      • # locate the appropriate modem driver from the Internet: 
         cd /tmp;
 wget http://linmodems.technion.ac.il/pctel-linux/pctel-0.9.6.tar.gz
      • # unpack the stuff: 
         tar -xzvf pctel-0.9.6.tar.gz
      • # configure the make files for your platform: 
         cd /tmp/pctel-0.9.6
 ./configure --with-hal=i8xx
      • # make and install the stuff if successful: 
         if make;then sudo make install;else echo problem making the stuff =============;fi
      • # make sure that the modem modules are loaded at boot time: 
         echo pctel >> /etc/modules-`uname -r`
 echo ptserial  >> /etc/modules-`uname -r`
  2. # configuring the dial in program wvdial:
    • # run the configuration program (if this program does not seem to find your modem, you may have a problem which is not within the scope of this page: read the INSTALL and README files of the modem driver software, e.g., at http://linmodems.technion.ac.il/pctel-linux): 
       sudo wvdialconf /etc/wvdial.conf
    • # Note that this program probably terminates mentioning where your modem has been found, e.g., 
       Found a modem on /dev/ttyLT0, using link /dev/modem in config.
      indicates that the modem device is /dev/ttyLT0
    • # edit /etc/wvdial.conf to specify the phone number you wish to dial, the userid that must be used, and the password which should be presented: 
       joe /etc/wvdial.conf
      This file typically looks like this: 
      [Dialer Defaults]
Modem = /dev/modem
Baud = 115200
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
ISDN = 0
Modem Type = Analog Modem
Phone = <Target Phone Number>
Username = <Your Login Name>
Password = <Your Password>
  3. # test your modem configuration: 
     sudo wvdial
  4. # if the program claims not to be able to detect /dev/modem, you should create a symbolic link pointing to the modem device (assume /dev/ttyLT0 is reported by the wvdialconf program ): 
     ln -sf /dev/ttyLT0 /dev/modem
  5. # you can now use your modem to dial to your Internet service provider using: 
     sudo wvdial

Additional information

  1. # you can read additional information on popular modem tools at the Modem-HOWTO. This page gives tips for software to deal with fax, dialback, statistics, etc.