A serial port is a computer interface that transmits data one bit at a time. In common use, the term “serial port” refers to ports that use a particular asynchronous protocol. These ports include the RS-232 ports on PCs and many serial ports in embedded systems. Most serial ports are bidirectional: they can both send and receive data. Transmitting one bit at a time might seem inefficient but has advantages, including the ability to use inexpensive cables and small connectors. | SERIAL PORT COMPLETE I EDITION COM PORTS USB VIRTUAL COM PORTS AND PORTS FOR EMBEDDED SYSTEMS author of USB COMPLETE Design serial links and networks Access devices with .NET Program microcontrollers for serial communications Use wireless technologies JAN AXELSON Serial Port Complete COM Ports USB Virtual COM Ports and Ports for Embedded Systems Second Edition Jan Axelson Lakeview Research LLC Madison WI 53704 Serial Port Complete COM Ports USB Virtual COM Ports and Ports for Embedded Systems Second Edition Jan Axelson Copyright 1998 1999 2000 and 2007 by Janet L. Axelson All rights reserved. No part of the contents of this book except the code examples may be reproduced or transmitted in any form or by any means without the written permission of the publisher. The code examples may be stored and executed in a computer system and may be incorporated into computer programs developed by the reader. The information computer programs schematic diagrams documentation and other material in this book are provided as is without warranty of any kind expressed or implied including without limitation any warranty concerning the accuracy adequacy or completeness of the material or the results obtained from using the material. Neither the publisher nor the author shall be responsible for any claims attributable to errors omissions or other inaccuracies in the material in this book. In no event shall the publisher or author be liable for direct indirect special incidental or consequential damages in connection with or arising out of the construction performance or other use of the materials contained herein. MPLAB PICDEM and PIC are registered trademarks of Microchip Technology Inc. in the . and other countries. Other product and company names mentioned herein may be trademarks of their respective holders. Published by Lakeview Research LLC 5310 Chinook Ln. Madison WI 53704 On the web at Distributed by Independent Publishers Group . 14 13 12 11 .
