How do I get the COM port to function?

logike30 · 06-08-2006, 12:03 AM

I am quite new to the linux world. I have myself started on SUSE 10.1. I have been having trouble getting one of my programs which uses the COM port for RS232 communication to function. The program is a windows based program that I have gotten to run using Wine. It doesn't seem to identify the com port and is unable to communicate with the equipment I connect to. Is there something I need to do to get this thing working?

Thanks

bigrigdriver · 06-08-2006, 05:21 PM

Windows and Linux don't give the com ports the same names. The windows to Linux conersion looks like this:
COM1 == /dev/ttyS0
COM2 == /dev/ttyS1
COM3 == /dev/ttyS2
COM4 == /dev/ttyS3

So, check the application configuration. Edit to point to the appropriate /dev/ttySx instead of a COMx port. Even though it's a windows app, it is working through Wine and the Linux kernel to communicate with the com port, so it should work if it uses the Linux port names.

logike30 · 06-09-2006, 09:05 PM

I'll give it a try, thanks!

gtrawoger · 06-09-2006, 11:43 PM

Don't forget to make your ports read/writable. From what I remember they are assigned to root.

I remember trying to hook up my PDA over the serial port and had a couple frustrating hours in there until I figured out to give myself privileges to the access.

linmix · 06-10-2006, 06:02 AM

Would you mind sharing how you did that. I'm having the same kind of trouble with a perallel port

gtrawoger · 06-10-2006, 08:20 AM

Sure,

- open a terminal and get to be root.

- type "chmod a+rw /dev/ttyS0" for COM1 (or whatever port you need open.)

If you still have problems, maybe check out this article:

http://www.linuxforums.org/forum/per...llel-port.html

Cheers

gtrawoger · 06-10-2006, 08:42 AM

Actually, come to think of it, I did it a different way. The above is probably the quickest to get it working.

But what I did (since I am a Linux newbie and used to Windows) I opened konqueror in SUPER-USER mode.
Then I went to the /dev directory, and right clicked on the ttyS0 icon, going to permissions and allowed all access.

Either way should work though.

linmix · 06-10-2006, 04:19 PM

Thanks for the information!

logike30 · 06-11-2006, 05:22 AM

What is a Super-user?

wilsonsamm · 06-11-2006, 12:23 PM

A super user (or username "root") is a user account on most linux/unix/bsd systems that have the permissions to do anything at all, even deleting essential files and things. This is the reason we use super user for doing most config.

linmix · 06-11-2006, 06:11 PM

LQwiki: super user

gtrawoger · 06-11-2006, 09:46 PM

Quote:

Originally Posted by logike30

What is a Super-user?

logike30,

Again, what I did to get the Super-User (root) Konqueror window is simply open a terminal window and login in as root:

# su
Enter Password:

Enter your password, and then type:

konqueror &

A new "Explorer" type window will pop up and you can then go to "/dev/" and change permission in that file browser window. Just be careful what you are doing in there, since you can change your whole system and toast it.

Hope that helped.

logike30 · 06-12-2006, 12:37 AM

Ahh, superuser = root. Now I know.