A Linmodem is the Linux implementation of a "winmodem" (see disclaimer). These devices are 'less than' a modem in the sense that they depend on software to perform, to a greater or lesser extent, the functions traditionally handled by modem hardware. The rationale for this is, of course, that software is cheaper than hardware, and can be upgraded/expanded/improved without the use of screwdrivers (usually); however, for the modem to function at all, one requires software that can run on one's preferred operating system.
An ever-growing number of winmodems will work under Linux. Each chipset for which a driver is known to exist has a section in this document, below, describing its installation. Any other chipset has no known support under Linux (at least, not known to us).
The information about installed hardware using commands such as:
dmesg | moreand
MarvS notes that the Device Manager under Windows can provide similar information, but it should be noted that a manufacturer will often simply put its brand name on a built-in modem, so this information may not be as useful as you might hope (e.g., what chipset does a "Compaq Internal 56k" modem have?). Additional information may sometimes be obtained by making a modem log, implemented under MS Windows as a check box option within the Dial Up Networking menus. The file produced is
C:\WINDOWS\MODEM.LOG. It will contain the modem initialization strings, and perhaps also the name of the modem configuration file, which may also contain other useful information.
If you know the precise name of your modem, you can try searching the large Linux Modem Compatibility Database at Rob Clark's site. The color/letter code on the left side of the table will indicate if your modem is known to function or not under Linux. The code "LM" indicates a Linmodem, and the modem notes should indicate which driver you need. A "WM" means it's a winmodem, but no Linux support is known to exist. Be careful not to assume that modems with similar names will contain the same chipsets, or will necessarily behave similarly whatsoever! Your WhizBang LX56 and your friend's WhizBang GT56 could have entirely different innards.
If you do not know the precise name of your modem, you can search based on the identification number of the modem ( on every modem there must be printed a registration number, which may either be the board producer's designation, or, alternatively, an FCC registration number. An example photo of such an ID number on a modem board can be found at http://www.idir.net/~gromitkc/fcc1.jpg on Rob Clark's site.) Use your web browser's "Find in Page" to search his table of modems and FCC ID's to obtain chipset/driver information. Alternatively, you can directly search the US Federal Communications Commission (FCC) database at http://www.fcc.gov/oet/fccid/. Read the directions carefully, and be careful not to confuse O (the letter) with 0 (the number), and other possible mixups.
You may not be able to obtain the FCC ID number if you have a laptop which you prefer not to open up, or are looking to buy a particular machine and the vendor has not been polite enough to provide you with the information nor a sample box for you to take apart and play with. In these cases, you might try: