1.9Quick Install

Very Quick Install

If you think your modem will work under Linux and needs no special driver, then just physically install/connect it. Start you computer, watch the boot-time messages for Linux to find the modem. Note it's the serial port number such as ttyS2 (/dev/ttyS2). Connect a phone line to it and dial out with say wvdial (after configuring wvdial). If the above doesn't work, read on.

Will my modem work under Linux?

So called "winmodems" will work under Linux only if a driver for it exists and gets installed. In this case it's called a "linmodem" since it can be made to work under Linux. See modem list and Software-based Modems (winmodems). There's no point of installing a modem that will not work with Linux.

External Serial Modem Install

At one time (2002 ?) no external serial modem was a winmodem but that's no longer the case. With a straight-thru or modem cable, connect the modem to an unused serial port on the PC. Make sure you know the name of the serial port: in most cases COM1 is ttyS0, COM2 is ttyS1, etc. You may need to check the BIOS setup menu to determine this. Plug in the power cord to provide power to the modem. See All Modems for further instructions.

Internal Modems (ISA, PCI and AMR)

If the modem is both PnP and directly supported by the serial driver (kernel 2.4 +) or by a winmodem driver that you've installed, then there is no configuring for you to do since the driver should configure it.

To physically install a modem card, remove the cover of the PC by /removing some screws. Find a matching vacant slot for the card next to the other adapter cards. Before inserting the card in the slot, remove a small cover plate on the back of the PC so that the telephone jacks on the card will be accessible from the rear of the PC. Then carefully align the card with the slot and push the card all the way down into the slot. Attach the card with a mounting screw (usually 3mm, .5mm pitch --don't use the wrong size).

You may watch the boot-time messages to see if your modem is detected. Use "dmesg" to see them or shift-page-up to scroll the screen back after they have flashed by.

Internal Modems: Manual configuration

Normally, you don't need to do this manual configuration since the modem's serial port may be detected and assigned a port at boot-time. For example: ttyS14 at I/O 0x6450 (IRQ = 10). Otherwise (or if there is some special reason to change the configuration) then you need to configure it yourself (or perhaps update your kernel to increases the likelihood that the modem gets detected). If your modem has no ttyS number assigned to it, it can't be used until it gets a ttyS number (like ttyS10). It thus can't be detected by application programs such as dialers or minicom. But it might be found by using say "lspci -v" if it's on the PCI bus.

Finding a lost modem may not be easy and you may need to read a lot more of this HOWTO. Once found, you need to use the "setserial" program to manually assign it to an available ttyS? port of your choice . For this you need to know both it's IO address (such as 0x6450) and its IRQ (such as 10). In the worst case, the modem has been disabled by a failing to be detected and enabled by the BIOS (or Linux) and doesn't have any IO address nor IRQ number. But you may still be able to find it. Older modems could be disabled by a jumper on the card or in rare cases by MS software.

You may have some choice of IRQs and IO addresses (including the case where you are able to change what the BIOS has set). See Choosing Serial IRQs and Choosing Addresses.

Old ISA Modems

ISA modems normally use ttyS0 - ttyS3. For old modems with jumpers look at the modem manual or look for printing on the modem card that tells you what the jumpers do. They have standard

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* Modem How-To Index