Modems for a Linux PC 2.1 External vs. Internal A modem for a PC may be either internal or external. Internal modems are less expensive, are less likely to to suffer data loss due to buffer overrun, usually use less electricity, and use up no space on your desk. External modems are usually easier to install and usually require less configuration. They have lights which may give you a clue as to what is happening and aid in troubleshooting. The fact that the serial port and modem can be physically separated also aids in troubleshooting.
External modems are easy to move to another computer.
For details Can't Set a High Enough Speed Internal modems present a special problem for Linux, but will work just as well as external modems provided you avoid the ones that will work only for MS Windows. If you buy a new one that you're not sure will work under Linux, try to get an agreement that you can return it for a refund if it doesn't work out. Let a PnP BIOS do the configuring The last 2 items of the above have shortcomings. If you want the PnP BIOS to do the configuring, all you need to do is to make sure that it knows that you don't have a PnP operating system. Many Linux users still say that it's a lot simpler just to get an external modem and plug it in.