Serial ports - totally out of ideas

[dkm777]

Hi guys,

I have an assignment of connecting some proprietary controller through a serial port to a server running the latest Ubuntu Server. This server uses an Intel 2500CC mainboard and that controller just refuses to talk to its software. The guy who made it says there should be constant data stream coming from the controller, but when I do 'cat /dev/ttyS[0123]' I get silence. I read somewhere that there might be a problem with permissions, i.e. the user I'm testing this under has no permission to access the serial ports, but if that was the case shouldn't I be getting an error message? Also the guy who made this thing is stuck in the Windows world and keeps referring to the serial ports as COM1, COM2, etc. But this is Linux, there is no such thing as COM1 and stuff. I'm really stumped. Maybe all the serial ports are dead? But if that was the case, wouldn't I be getting error messages during boot? Is there ANY way of testing the serial ports under Linux? Any help is greatly appreciated.

 

[Jodell88]

I've never used serial ports before. Here's a site that has a few commands that may let you know if they are working or not.

http://www.cyberciti.biz/faq/find-out-linux-serial-ports-with-setserial/

 

[Red Squirrel]

I have seen some really weird behavior talking with serial ports and cat sometimes work but other times does not. Depends on the device. Try to see if you can use a program like picocom.

 

[dkm777]

OK, solved the problem by adding the user the stupid app runs on to /etc/sudoers. But then again this is just asking for trouble from security perspective...

 

[Jodell88]

Um, what happened to sudo <insert command> ?

 

[Red Squirrel]

If you want to automate something you can't be getting prompted for a password, not to mention it can be annoying. TBH I usually just do su - and do everything I have to do. Not the proper way but if I have multiple commands to run I don't feel like typing my password so many times.

Not sure why that would have solved the OP's problem though...

 

[dkm777]

I'm not sure how that solved the problem as well 🙂. Looks like the guys who wrote the firmware for the controller ant the data collection software are nothing but voodoo programmers. My bigger concerns are that there's also a PHP/MySQL webpage needed to display the data that is collected and those services have to be run under root privileges as well or the data just doesn't show up. I strongly advised to seal this server from the outside world, because running Apache and MySQL as root is essentially an invitation for massive a**rape.