1. Introduction

This is the Linux Serial Programming HOWTO. All about how to program communications with other devices / computers over a serial line under Linux. Different techniques are explained: Canonical I/O (only complete lines are transmitted/received), asyncronous I/O, and waiting for input from multiple sources.

This is the first update to the initial release of the Linux Serial Programming HOWTO. The primary purpose of this update is to change the author information and convert the document to DocBook format. In terms of technical content, very little if anything has changed at this time. Sweeping changes to the technical content aren't going to happen overnight, but I'll work on it as much as time allows.

If you've been waiting in the wings for someone to take over this HOWTO, you've gotten your wish. Please send me any and all feedback you have, it'd be very much appreciated.

All examples were tested using a i386 Linux Kernel 2.0.29.

1.1. Copyright Information

This document is copyrighted (c) 1997 Peter Baumann, (c) 2001 Gary Frerking and is distributed under the terms of the Linux Documentation Project (LDP) license, stated below.

Unless otherwise stated, Linux HOWTO documents are copyrighted by their respective authors. Linux HOWTO documents may be reproduced and distributed in whole or in part, in any medium physical or electronic, as long as this copyright notice is retained on all copies. Commercial redistribution is allowed and encouraged; however, the author would like to be notified of any such distributions.

All translations, derivative works, or aggregate works incorporating any Linux HOWTO documents must be covered under this copyright notice. That is, you may not produce a derivative work from a HOWTO and impose additional restrictions on its distribution. Exceptions to these rules may be granted under certain conditions; please contact the Linux HOWTO coordinator at the address given below.

In short, we wish to promote dissemination of this information through as many channels as possible. However, we do wish to retain copyright on the HOWTO documents, and would like to be notified of any plans to redistribute the HOWTOs.

If you have any questions, please contact

1.2. Disclaimer

No liability for the contents of this documents can be accepted. Use the concepts, examples and other content at your own risk. As this is a new edition of this document, there may be errors and inaccuracies, that may of course be damaging to your system. Proceed with caution, and although this is highly unlikely, the author(s) do not take any responsibility for that.

All copyrights are held by their by their respective owners, unless specifically noted otherwise. Use of a term in this document should not be regarded as affecting the validity of any trademark or service mark.

Naming of particular products or brands should not be seen as endorsements.

You are strongly recommended to take a backup of your system before major installation and backups at regular intervals.

1.3. New Versions

As previously mentioned, not much is new in terms of technical content yet.

1.4. Credits

The original author thanked Mr. Strudthoff, Michael Carter, Peter Waltenberg, Antonino Ianella, Greg Hankins, Dave Pfaltzgraff, Sean Lincolne, Michael Wiedmann, and Adrey Bonar.

1.5. Feedback

Feedback is most certainly welcome for this document. Without your submissions and input, this document wouldn't exist. Please send your additions, comments and criticisms to the following email address : .