The Linux Serial HOWTO

by Greg Hankins, greg.hankins@cc.gatech.edu

1. Introduction

1.1 Copyright

1.2 Other sources of information

1.3 New versions of this document

1.4 Feedback

1.5 Disclaimer

2. Supported serial hardware

2.1 Multiport serial boards (with 16450/16550A UARTs)

2.2 Intelligent multiport serial boards

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?

4.1 About getty_ps

4.2 About mgetty

4.3 About agetty

5. What is setserial?

6. What is setserial?

6.1 Hardware requirements

6.2 Talking to your modem

6.3 Dial out modem configuration

6.4 Hardware flow control

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

7.1 Dial in and out modem configuration

7.2 Installing getty_ps

7.3 Setting up uugetty

7.4 Customizing uugetty

7.5 US Robotics Notes

7.6 Supra Notes

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

8.1 Hardware requirements

8.2 Setting up getty

8.3 Notes on setting up a PC as a terminal

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

9.1 Choosing serial device interrupts

9.2 Setting serial device addresses

10. irqaddr

11. spdhi

12. Serial Tips

12.1 kermit and zmodem

12.2 Setting terminal types automagically

12.3 Color ls on serial connections

12.4 Printing to a printer connected to a terminal

12.5 Can Linux configure the serial devices automagically?

13. Linux FTP sites

14. One step further...

14.1 What are lock files?

14.2 ``baud'' vs. ``bps''

14.3 ``baud'' vs. ``bps''

14.4 What's the real difference between the /dev/cuaN and

15. Troubleshooting

15.1 I keep getting ``line NNN of inittab invalid''.

15.2 When I try to dial out, it says ``/dev/cuaN: Device or resource busy''.

15.3 I keep getting ``Id SN respawning too fast: disabled for 5 minutes''.

15.4 Serial devices are slow or serial devices can only send in one direction.

15.5 My modem is hosed after someone hangs up, or uugetty doesn't

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

15.7 At high speeds, my modem loses data.

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

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

15.10 My screen is printing funny looking characters.

15.11 getty or uugetty still doesn't work.

16. Contributions