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Old 10-15-2013, 01:16 PM   #1
Stuferus
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Question Serial console (or something like it) over distance..


hi,

First, if this is wrong in the slackware section a mod may please move this to where it belongs.
Second, please excuse my english as im from germany.

to my question/problem.

I've installd slackware 14 on my little atom box as a server/router, all fine and nice.

I'll had to take and move my mothers display for installation and now as im in configuration (dont have a generic kernel etc yet) i far if something may go wrong, i would need to steal me her monitor again..

my computer is ~15 m from the atom box away.. the atom box is sitting in the living near the dsl modem and stuffs for my internet connection, my computer is in the next room over aka my room.

my question is.. how could i get a serial console 15m to my computer or are there other means to - without buying a display, see the boot live on my computer?

i hope im understood..

btw. i frashly wired the whole place with cat6 cableing.. if there would be a way to get the serial over the lan.. *thinking*

thanks for help or any comments on this.

Last edited by Stuferus; 10-16-2013 at 07:39 AM.
 
Old 10-15-2013, 01:39 PM   #2
michaelk
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I would say that 99.99% of the time once the OS is up and running all you would require is access via ssh. ssh is a secure remote console shell that connects via the LAN. I have several headless systems in remote locations that I physically only touch once or twice a year.
 
Old 10-15-2013, 02:31 PM   #3
55020
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If you want to see boot messages over the network, look at the netconsole kernel module.
https://www.kernel.org/doc/Documenta...netconsole.txt
http://www.cyberciti.biz/tips/linux-...-tutorial.html
https://wiki.archlinux.org/index.php/Netconsole

But netconsole will only send log messages to another computer, it won't do two way communication like a serial console. So... if you are really crazy, get an old router from someone -- many routers have a hidden serial port on the circuit board (but not all of them). With soldering (and probably a voltage converter from 3.3V to 5V) and installing OpenWRT, you can connect the router's serial port to your atom box's serial port, and log in to the router from the network, and use minicom to communicate with the atom box
 
Old 10-15-2013, 02:43 PM   #4
Stuferus
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Quote:
Originally Posted by michaelk View Post
I would say that 99.99% of the time once the OS is up and running all you would require is access via ssh. ssh is a secure remote console shell that connects via the LAN. I have several headless systems in remote locations that I physically only touch once or twice a year.
so you have not understood me.. great

ill need the to see the system boot, remote.. but my pc is 15 meters away.. i dont think serial goes 15 meters. and i will not convert to feet for you
 
Old 10-15-2013, 02:45 PM   #5
Stuferus
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Quote:
Originally Posted by 55020 View Post
If you want to see boot messages over the network, look at the netconsole kernel module.
https://www.kernel.org/doc/Documenta...netconsole.txt
http://www.cyberciti.biz/tips/linux-...-tutorial.html
https://wiki.archlinux.org/index.php/Netconsole

But netconsole will only send log messages to another computer, it won't do two way communication like a serial console. So... if you are really crazy, get an old router from someone -- many routers have a hidden serial port on the circuit board (but not all of them). With soldering (and probably a voltage converter from 3.3V to 5V) and installing OpenWRT, you can connect the router's serial port to your atom box's serial port, and log in to the router from the network, and use minicom to communicate with the atom box
interesting idea.. ill have a look in to that.. but its not really what i need.. what if the kernel does not boot as something has gone wrong with lilo? and no.. i dont think i have money for a keyboard video mouse (kvm) thingy :-S
 
Old 10-15-2013, 03:22 PM   #6
55020
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Quote:
Originally Posted by Stuferus View Post
i dont think serial goes 15 meters
At 9600 baud, it probably will. If it doesn't work, try 2400... 1200... or 110, 110 used to be good enough for everybody

Quote:
Originally Posted by Stuferus View Post
what if the kernel does not boot as something has gone wrong with lilo?
You can configure both LILO and Linux to use the serial port as a console.
http://www.tldp.org/HOWTO/Remote-Ser...WTO/index.html
But there are plenty of ways to break it (just like a vga console). The answer is to be very careful and maybe have a second LILO entry that boots an emergency partition.
 
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Old 10-15-2013, 03:42 PM   #7
michaelk
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There is lots of documentation on how to configure a serial console. Yes it will, the recommended distance for 9600 baud (RS-232) is 15M which is sufficient for a console terminal but you should be able to go faster.

There are many terminal applications to choose from both windows and linux, putty, hyperterminal, cutecom, kermit or minicom.
 
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Old 10-15-2013, 03:59 PM   #8
Stuferus
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thanks.. now i need to find a 15m long cable.. lol, - nullmodem it was right?

thanks every one for the quick help.. as long as i can see lilo im fine.. dont need access to bios..

solved.
 
Old 10-15-2013, 04:03 PM   #9
michaelk
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Correct, a null MODEM cable is required when connecting two computers together.
 
Old 10-15-2013, 04:04 PM   #10
TB0ne
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Quote:
Originally Posted by Stuferus View Post
so you have not understood me.. great
No, we did, but you didn't understand the point michaelk was making.

Analyze your NEEDS, not your WANTS. You may WANT to have this working, but honestly...how often does it go down/reboot? If you hardly ever have to touch it, why is it an issue to have an always-ready console? Wouldn't it be simpler just to put a monitor on it a few times a year?
Quote:
ill need the to see the system boot, remote.. but my pc is 15 meters away.. i dont think serial goes 15 meters. and i will not convert to feet for you
As suggested, lowering the speed may work for you...and a good way to find out if it will work is to just put a cable on it and try it. Using low-capacitance cables, you can get up to 1000 feet at full speed.

And according to the TLDP article:
http://www.tldp.org/HOWTO/Remote-Ser...-distance.html

..you can get 9600 baud at 15 meters just fine. Barring that, you can get a serial-to-network device:
https://gridconnect.com/rs232-ethern...FXRp7Aodwx8Atw


:: edit ::
...and apparently everyone was typing when I was.

Last edited by TB0ne; 10-15-2013 at 04:05 PM.
 
Old 10-15-2013, 04:56 PM   #11
mostlyharmless
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I had the same problem, but found a cheap monitor (20 USD), used, from Goodwill (an emporium of used, donated items). Perhaps a garage sale or something of the sort is available in Germany. Some furniture stores or other businesses seem to have large numbers of 15 inch vga lcds, just lying around. It might be worthwhile.
 
Old 10-16-2013, 04:44 AM   #12
Stuferus
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Originally Posted by mostlyharmless View Post
I had the same problem, but found a cheap monitor (20 USD), used, from Goodwill (an emporium of used, donated items). Perhaps a garage sale or something of the sort is available in Germany. Some furniture stores or other businesses seem to have large numbers of 15 inch vga lcds, just lying around. It might be worthwhile.
ill yet have to find something like this.. i would be kinda good to have a monitor for it if i need it, but i think the serial console is a good alternative..

and yes, ill use ssh 95% of the time.. the box is totaly headless for 2 years and i needed my moms tft only 5 times as of now.. now would be the 6x, if something would go wrong with switching to generic or upgrading to 14.1 if it is out (i dont go for unfinished stuff - not really safe sry patrick, no offense)

its quite important that the box is running.. i dont life alone and the others would cut my head off if its down to long :-S - no not really but you get the point.
 
Old 10-16-2013, 04:48 AM   #13
Stuferus
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Originally Posted by TB0ne View Post
Barring that, you can get a serial-to-network device:
https://gridconnect.com/rs232-ethern...FXRp7Aodwx8Atw
no i dont think i need that
 
Old 10-19-2013, 02:20 AM   #14
vdemuth
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As another alternative which hasn't been mentioned yet. You could maybe look into using a KVM, which will work over the network and allow you to just plug your own monitor in instead of using your moms.
 
Old 10-19-2013, 06:44 AM   #15
Stuferus
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As another alternative which hasn't been mentioned yet. You could maybe look into using a KVM, which will work over the network and allow you to just plug your own monitor in instead of using your moms.
i dont have or want pay 200-500 eur - why? dont have them.
but thx. i was thinking about it as ive seen that intel puts kvms on some boards. but its really to expensive for me.
 
  


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