Appendix C – Installing a Modem Under Linux
Multi-Tech Systems, Inc. MT5600BA-V92 User Guide 49
Appendix C - Installing a Modem Under Linux

Introduction

This appendix explains how to install a modem on a computer operating under the Red Hat Linux 6.2
operating system. Other versions of Red Hat and other Linux operating systems should be similar. Briefly,
in Linux, you do not need drivers for most standard external modems and most internal ISA bus modems.
Programs in Linux commonly call upon the port, rather than the modem.

Standard Linux Serial Port Definitions

PC port Linux port
Com1 ttyS0
Com2 ttyS1
Com3 ttyS2
Com4 ttyS3

Installation

Connect the external modem to an available serial port.

Setup

This section describes how to make sure Linux can talk to the modem and be able to dial up to the
Internet. Linux can use different programs and desktops depending on who made the Linux operating
system and what version it is. The following procedures use the most commonly installed components of
Red Hat 6.2. More information can be found in your Linux OS owner’s manual.

Using the Terminal Program Minicom to Verify Operation

1. At the command prompt, type minicom –s and press Enter.
2. Select Serial port setup and press Enter.
3. From Serial port setup, use the A key to access Serial Device, and then press Enter.
4. Press ESC.
5. You are now in the Minicom terminal. Type AT and press Enter. The LCD should display OK to
verify the operation. Alternately, dial a phone number to verify line operation
6. To leave Minicom, press CTRL + A, and then press Z.
7. On the help menu, press X to exit.

Using the Modem to Call the Internet

Linux allows different graphic user interfaces (GUI). In the following steps, we’ll use the Gnome Desktop
GUI and assume that the Internet Service Provider (ISP) you are calling assigns you the Domain Name
Service (DNS) and Internet Protocol (IP) addresses. For more information on DNS or IP, see the Linux
OS owner’s manual or contact your ISP.
1. On the Task Bar at the bottom of the LCD, select the Gnome Footprint.
2. Select Internet from the menu.
3. Select Dialup Configuration Tool.
4. Select Add, and then click Next.
5. Enter the connection name and phone number, and then click Next.
6. Enter your user name and password, and then click Next.
7. Select Normal ISP if your ISP is not listed, and then click Next.
8. Click Finish.