Trying to get a modem to work under Linux can be frustrating, irritating, and downright brutal. But it doesn’t have to be that way. Setting it up properly requires some patience and careful planning. Here I'll explain how to set up your modem to work under Red Hat 8 and offer a quick troubleshooting tip.
Make sure you have a Linux-compatible modem
Before you try to install and configure the modem, make sure it is Linux-compatible. To find out if a particular modem is Linux-compatible and obtain the appropriate driver, check the modem manufacturer's Web site, Red Hat's Hardware Compatibility List (HCL) and/or Linmodems.org.
Configuring a new dial-up modem
Once you've physically installed the modem and connected it to the phone line, log in as root, click the Main menu button, click System Settings, and select Network. This will open the Network Administration Tool, which is used to install and configure network devices such as network cards, ISDN modems, and dial-up modems. You can also start this utility from a shell prompt by issuing the command, redhat-config-network.
Once the Network Administration Tool is open, take a few moments to familiarize yourself with its four main tabs: Devices, Hardware, Hosts, and DNS. By default the Devices tab is selected and from here you can add, edit, copy, delete, and activate/deactivate various communication devices, such as network adapters and modems.
To add a new modem make sure the Devices tab is selected, then click Add, select Modem connection from the Device Type list, and click Forward. If you have already configured your modem on the machine's hardware list, the Network Administration tool will use that one to make the connection. If no modem is configured, the Network Administration Tool will search for one. When the search is complete, you will be asked to select the appropriate modem device, set the modem's volume, baud rate, flow control, and use of Touch-Tone dialing. Once you have configured the modem, click Forward.
You will then be asked to enter information about your ISP, such as phone number, user name, and password. Enter the required information and click Forward. The Create Dialup Connection screen will appear displaying the information you have just entered; click Apply. You will return to the main Network Administration Tool window, and the modem connection should appear under the Devices tab. Click Apply to save your new modem connection settings.
Once the modem has been added, you can further customize its configuration by clicking on the modem in the device list and clicking the Edit button. The Modem Dialup Configuration screen appears, and from here you can customize the modem by editing the information under the General, Route, Provider, Compression, Options, and Advanced tabs. But I recommend leaving the default settings unless you are an advanced Linux user. When you're finished making changes, click OK to save your settings and return to the Network Administration Tool's main window.
One final step before you can begin using your modem: By default new network devices are listed as inactive. You will need to activate your new modem by selecting the modem from the device list and clicking the Activate button.
Troubleshooting dial-up modem problems
So you’ve done all your homework, entered the correct configuration information, and the modem still fails to function properly. When this happens, you'll need to do some careful thinking and some intensive digging to find out what went wrong.
You might get an error message that says something like, “No modem detected” or there might not even be an error message. When this happens, your first step is to watch for hang-ups during the boot process. If you notice this happening, it's likely Linux cannot find the modem on the serial port you specified. Go back into the Network Administration Tool and ensure the modem is on the correct serial port.
If you don’t know on which serial port your modem is located, you can use a program called, WvDial to find it. WvDial is automatically installed during the typical Red Hat 8 installation and has two main components, wvdial and wvdialconf. For the purposes of this article, you should be concerned only with wvdialconf. When run, this program searches your serial ports for modems, determines the capabilities of any modem it finds, and saves this information to a configuration file. To run wvdialconf, enter wvdialconf at a shell prompt followed by a configuration file name. For example:
The results of wvdialconf's search will be displayed on the screen. If wvdialconf fails to find your modem, the problem may be that your modem isn't installed properly or isn't compatible with Linux. For more information on using WvDial check out Red Hat's Web site or Net Integration Technologies Web site.
If you still have trouble after trying WvDial, I recommend you read Modem-HOWTO from LinuxPlanet.com.