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Ubuntu 9.04 Serial application to telnet to serial device


 
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Operating Systems Linux Ubuntu Ubuntu 9.04 Serial application to telnet to serial device
# 1  
Old 10-08-2009
Power Ubuntu 9.04 Serial application to telnet to serial device

Hello!

I am working on an application which reads environmental instruments which have serial ports. The application requires a serial port to be present to talk to the device (i.e. /dev/ttyS0 ). In some instances the environmental devices will be 100's of yards away from the computer, so a serial cable becomes a liability. In these scenarios we would like to use a multi-port terminal server which serves up multiple serial connections via telnet.

I have almost solved the problem...but need some help finishing. DETAILS:
The configuration we have is:

Computer/Ubuntu 9.04 --> Ethernet ----> Telnet Based Serial Device Server --> Serial Device

I have run remserial and am able to interact with the serial device using socat or netcat from the terminal. However, SJINN as with as other serial port viewers are unable to connect to the generated pseudo serial port. I get an error about ioctrl.

DETAILED STEPS I FOLLWED:

1) Create a file in /dev called “remserial1” and chmod this to 777.

2) Run
Code:
./remserial -d -r XXX.XXX.XXX.XXX -p 10001 -l /dev/remserial1 /dev/ptmx &

3) When I do the following command
Code:
socat - /dev/remserial1,raw,crnl &

I can interact with the serial device as if I had a serial connection to it.

The Issue: When I use a normal serial viewer (in this case SJINN or Serial Port Terminal gtkterm) with gtkterm I get “Control signals read: Invalid argument”. With SJINN I get an error involving ioctrl.

I believe that it has to do with trying to read a pseudo terminal, but am at my wits end Smilie, any advice would be appreciated. Also, before linking netcat or socat examples, please remember that an application on the computer must speak with a serial port, which is then relayed over telnet and back to a serial device without buying some serial port redirector package.
# 2  
Old 10-09-2009
Code:
1) Create a file in /dev called “remserial1” and chmod this to 777.

What is this file? How do you create it?

I might try putty's serial device option in raw mode.
# 3  
Old 10-12-2009
I used some command like
Code:
echo " " > /dev/remserial1; chmod 777 remserial1

I use PuTTy allot. I will try the raw mode. I do know that the pseudo terminal is in raw mode, maybe that's the ticket. Will write back when I try.Smilie

Quote:
Originally Posted by Corona688
Code:
1) Create a file in /dev called “remserial1” and chmod this to 777.

What is this file? How do you create it?

I might try putty's serial device option in raw mode.
# 4  
Old 10-13-2009
Putty in raw mode dosen't do it. I can use screen /dev/remserial1 and that works fine. I think I need to specify the baud rate and comm settings of the virtual device.
# 5  
Old 10-13-2009
Quote:
Originally Posted by mvona
Putty in raw mode dosen't do it.
What does it do, exactly?

Quote:
I can use screen /dev/remserial1 and that works fine. I think I need to specify the baud rate and comm settings of the virtual device.
Sounds like setting the baud rate is what these serial programs are failing on... it's not acting like a serial port, it's acting like a virtual terminal. A terminal emulator that insists on a real serial port might never accept it.

---------- Post updated at 02:34 PM ---------- Previous update was at 02:26 PM ----------

Quote:
Originally Posted by mvona
I used some command like
Code:
echo " " > /dev/remserial1; chmod 777 remserial1

That's a very odd way to create a device file... Have you tried not doing this and just letting remserial create the device itself?
# 6  
Old 10-30-2009
I thought that you needed a fifo file for simultating serial communication? You should try something along the lines of:
Code:
mkfifo /dev/remserial1


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