Toshiba A200 Laptop Internal Modem

This post is really old; so you've probably already found your answer by now. But just in case you haven't ...

Most laptop internal modems are "winmodems". That is, they aren't real modems. A real EXTERNAL modem is connected to a serial port via a serial cable. Linux doesn't talk to the modem itself, it talks to the serial port. The operating system's view of a serial port is the controller chip, such as a National Semiconductor 16550A UART (Universal Asynchronous Receiver/Transmitter) chip or its equivalent. A real INTERNAL modem includes such a controller chip hard wired to the modem circuitry on the same expansion board (or in some cases, such as laptops, on the motherboard). In other words, when you add a real internal modem to your computer, you are also adding another real serial port too. This serial port is permanently connected to the modem and cannot be connected to anything else. Real internal modems allow the manufacturer to save money by eliminating the case, power supply, modem state LEDs, etc. But as viewed by the operating system they are indistinguishable from a real external modem. The OS sees the UART chip and talks to it, just like with a real external modem.

A winmodem, loosely defined, does not have this UART controller chip. The functions provided by the controller chip are emulated by a software driver that consumes CPU cycles on the main processor. Often times other functions traditionally handled by special-purpose chips in the modem itself, such as error detection and correction and data compression and decompression, are also offloaded to a software driver that runs on the main CPU chip. This allows the modem manufacturer to save even more money on hardware, but also puts more of a strain on the main CPU. More importantly, the manufacturer must supply an operating-system-specific driver for the modem in order for it to work. And at the time of this writing, most modem makers only supply drivers for Windows. That is why they are called winmodems. Even some of the external modems now are winmodems. They can't eliminate the controller chip, since that's in your computer. But they can and do eliminate the error correction and data compression chips from the modem and make a software driver that runs on the main CPU perform those functions.

Very few winmodems have Linux drivers available for them. In a gesture of support for the Linux community, IBM released drivers for the Mwave ACP internal modem used in its Thinkpad 600 and 600E, for example. The mwavem Debian package provides support for this device. A winmodem with a Linux driver is sometimes called a linmodem. But for most winmodems, you're probably out of luck. See the winmodem HOWTO for more information. My advice: be it internal or external, get a real modem. Since laptops generally don't have expansion slots, that probably means an external modem. You might be able to find an internal modem which is PCMCIA or PC card. But make sure its a real modem, not a winmodem.