The Linux Serial HOWTO

by Greg Hankins, gregh@cc.gatech.edu

1. Introduction

1.1 Other sources of information

1.2 New versions of this document

1.3 Feedback

1.4 Disclaimer

2. Supported serial hardware

3. What are the names of the serial ports?

3.1 Major and minor device numbers of serial devices in /dev

4. What is getty_ps?

4.1 Installing getty_ps

5. What is setserial?

6. How do I dial out with my modem?

6.1 Hardware requirements

6.2 Talking to your modem

6.3 Dial out modem configuration

7. How do I dial in and out with my modem?

7.1 Dial in and out modem configuration

7.2 Example modem setup

7.3 Setting up uugetty

7.4 Customizing uugetty

8. How do I set up a terminal connected to my PC?

8.1 Hardware requirements

8.2 Setting up getty

9. Can I use more than 2 serial devices?

9.1 Choosing serial device interrupts

9.2 Setting serial device addresses

10. Can Linux configure the serial devices automagically?

10.1 Notes for multiport boards

11. How do I set up my serial ports for higher speeds?

12. Noteworthy communications programs and utilities

13. More serial tips

13.1 kermit and zmodem

13.2 Setting terminal types

13.3 Color ls on serial connections

14. Linux FTP sites

15. What are locks?

16. What are UARTs? How do they affect performance?

17. Troubleshooting

17.1 I keep getting "line nnn of inittab invalid"

17.2 When I try to dial out, it says "/dev/cuan: Device or resource busy"

17.3 I keep getting "Id Sn respawning too fast: disabled for 5 minutes"

17.4 I have a modem/terminal connected, but root can't login on it.

17.5 I have my terminal connected to my PC, but after I type in a login name,

17.6 At high speeds, my modem looses data!

17.7 On startup, Linux doesn't report the serial devices the way I have

17.8 rz and or sz don't work when I call my Linux box on my modem.

17.9 getty or uugetty still doesn't work.

18. Contributions