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8. Appendix A: Installing Linux from a DOS machine

In the original Emacspeak HOWTO, James Van Zandt provided instructions on how to install Linux from a DOS machine using a null-modem cable. As with the other instructions in this HOWTO, I tried, unfortunately without success, to duplicate this procedure. However, I have provided the information gathered during testing in the following section. If you successfully install Linux from a Windows™ or DOS™ machine over a null-modem cable, please let me know the procedure you followed and I'll include it here.

Please note that the original instructions for installing Linux over a null modem cable were written for a DOS machine. I first attempted to reproduce these instructions with my Windows 2000 machine (from the DOS prompt) and Red Hat 7.1. Although I successfully downloaded and installed JAWS for DOS (available from Freedom Scientific at, I was unable to get a DOS VT100 terminal emulator installed. I tried using TELIX, which was popular several years ago, but when I tried to install TELIX version 3.51, I got a runtime error. Since I was unable to find any other DOS terminal emulators, I decided to try using a Windows screenreader and terminal emulator instead. This section documents the procedure I tried with the Windows machine.

8.1. Requirments

For this process, you will need a machine with a working speech synthesizer and a terminal emulator program. For my test, I used a Windows 2000 machine and tried both Narrarator (which comes with Windows 2000) and JAWS for Windows v.3.5. For the terminal emulator, I used tried both Hyperterminal (which comes with Windows) and CRT (which can be downloaded from You will also need a second machine (on which to install Linux), a null modem cable, and a copy of your preferred Linux distribution on either floppy disk or CD-ROM.

8.2. Connecting the computers

To connect the two computers, you need a "null modem" cable. A "null modem" cable is a serial cable that connects ground to ground and transmits on each end to receive on the other. The cable that comes with the DOS applicationLapLink will work fine. The LapLink cable is particularly handy because it has both a 9 pin and a 25 pin connector on each end. Alternatively, you may be able to find a null modem cable at your local computer store, or you can have one made. If you choose to have one made, here are the required connections:

  • For two 9 pin connectors, connect pin 2 (receive data) to pin 3, pin 3 (transmit data) to pin 2, and pin 5 (signal ground) to pin 5.

  • For two 25 pin connectors, connect pin 2 (receive data) to pin 3, pin 3 (transmit data) to pin 2, and pin 7 (signal ground) to pin 7.

  • For a 9 pin connector (first) to a 25 pin connector (second), connect pin 2 (receive data) to pin 2 (transmit data), pin 3 (transmit data) to pin 3 (receive data), and pin 5 (signal ground) to pin 7 (signal ground).

Once you have your null modem cable, you'll need to connect the two machines while both of them are off. It's easiest to use COM1 on both machines. Once you've got them connected, you're ready to start them up, as discussed in the next section

8.3. Installation

Once your machines are connected via the null modem cable, boot the DOS/Windows machine, then start the terminal emulation program. For my test, I tried both Hyperterminal (which comes with Windows 2000) and CRT (which can be downloaded from For some reason, the arrow keys did not work in HyperTerminal, making navigation within the HyperTerminal window impossible. However, the arrow keys (as well as Tab and Return) do work in CRT, so I recommend using CRT as your terminal emulator.

Set the terminal emulator for 9600 baud, no parity, eight data bits, 1 stop bit. If "Flow control" is an option, select Hardware. Also be sure to set your terminal emulation mode to VT100. Start the terminal emulator connection (you won't get any data at this point, as your Linux machine should still be off).

Once you've set up the terminal emulator on your DOS/Windows machine, insert the "boot" floppy or CD into your Linux machine and boot the machine. With Red Hat, at the boot: prompt, I typed in the command linux text console=ttyS0. Note that the "s" in "ttyS0" is capitalized, and that's a "zero" at the end of the string, not a capital letter "o." Other distributions may require other strings, so if you know the syntax required for distros other than Red Hat, please let me know and I will include that information here.

Once you've typed in this string at the boot: prompt and hit Return, you should get output in your terminal emulator program on your DOS/Windows machine. Unfortunately, at this point I discovered that neither JAWS for Windows nor Narrarator produces speech output in either the HyperTerminal or CRT terminal windows. This ultimately stymied my attempts to install Linux over a null modem cable.