Re: Pipelining COM ports

Knute Johnson <>
Tue, 14 Nov 2006 16:02:10 -0800
<6Os6h.219876$or7.105467@newsfe08.phx> wrote:

Thomas Fritsch wrote:

May be that works:
   RandomAccessFile raf = new RandomAccessFile("COM10", "rw");

I had tried that as well. :-) The problem is that I can't read the
response from the other side (mobile phone in my particular case). I
can read only data that I sent to that port. The same problem was in C,
I could not use the ordinary files there as well.

I found the solution: Java Communications API can be downloaded from
Sun's pages and it provides classes for communication with serial ports
(RS-232). I have problems configuring it because it does not display
any port on my computer, but I hope I'll solve that problem in next few

If you are using Winblows, put your files here and run the test code below.

JDK/jre/lib/ext comm.jar

JRE/lib/ext comm.jar
JRE/bin win32com.dll

import java.util.*;
import javax.comm.*;

public class Ports {
     public static void main(String[] args) {
         Enumeration e = CommPortIdentifier.getPortIdentifiers();

         while (e.hasMoreElements()) {
             CommPortIdentifier cpi =
              (CommPortIdentifier) e.nextElement();


Knute Johnson
email s/nospam/knute/

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