rec9140
Posts: 33
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KVM Switches Pi's and other

Sun Jan 27, 2019 5:17 pm

This is for KVM **SWITCHES** not the KVM virtualization method..

The main monitor I need to use have VGA and DVI inputs... I use a HDMI to DVI cable right now, and just switch it from Pi to Pi when I need it..

ssh is great for 95% of the time, but there are times I need to work locally with the Pi's.... due to the way some things are plugged in the USB ports are somewhat blocked so swapping a USB keyboard/mouse in and the DVI cable is not convenient...

So I am looking for a KVM which will deal with the HMDI to DVI output, either in the HARDWARE itself, or I just get HDMI to DVI cables to plug into the KVM... it would be a plus if it was just HDMI to KVM and then out to the monitor, but I am probably asking for trouble and more than I want to spend as well...

Yes, COST, as in CHEAP ! Is key... I'd prefer the actual UNIT itself and power supply be $99 or less. with 4 inputs... I'd consider more depending on cost and same for less for a steal....

X is NOT used 99.99999% of the time so VNC is not an option. These units are tasked with heavy loads and X running without need is wasted resources.. I only need X every now and then, and same with actual local use, but occasionally its needed instead of ssh and its mostly locally.

Any one got any KVM suggestions they like??? I'll take any input, and let me decide if its too much $$, or what not... but the key is that the monitor is DVI input only.. the VGA input is taken by another box i use the built in switch of the monitor to change between them when I need it..

Thanks!

W. H. Heydt
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Location: Vallejo, CA (US)

Re: KVM Switches Pi's and other

Sun Jan 27, 2019 6:00 pm

I'm using an Iogear 4-port Miniview. It's an HDMI/USB KVM. The way to handle your monitor with DVI input is to use HDMI cables between the Pis and the KVM and then use your HDMI to DVI cable on the shared output to the monitor. Or, of course, you could find a KVM switch that uses DVI and use HDMI to DVI cables from Pis to the switch and then a straight DVI cable to your monitor.

The big problem is that HDMI KVM switches are rather more expensive than VGA ones, and I fear it's not going to get any better, due to the increased bandwidth needed because 4K displays are becoming popular (and one can only wonder what will happen if/when 8K goes mainstream...).

My own set up is a bit more complex because I have some older systems that only have VGA output. So I take the HDMI output from the Iogear KVM, run it through a good (self powered) HDMI to VGA converter and then into one port of a 8-port VGA/PS-2 KVM, a Trendnet TK-802R. From there I use VGA to my Viewsonic VA2702w monitor.

Future plan is "reverse" part of that. As newer systems output HDMI and/or DVI, but not VGA, I want to get an 8-port HDMI/USB KVM to which I can slave on individual ports both the VGA/PS-2 KVM (using a VGA to HDMI converter) and the 4-port HDMI/USB KVM.

So...Yes. Pis work just fine through KVM switches.

hippy
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Location: UK

Re: KVM Switches Pi's and other

Sun Jan 27, 2019 6:49 pm

rec9140 wrote:
Sun Jan 27, 2019 5:17 pm
Yes, COST, as in CHEAP ! Is key...
If cost really is key then you could get by with a multi-way HDMI selector and a separate switch box which manually switches a USB Hub with your keyboard, mouse and whatever between multiple Pi's.

https://www.raspberrypi.org/forums/view ... 2#p1419761

W. H. Heydt
Posts: 10881
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Re: KVM Switches Pi's and other

Sun Jan 27, 2019 9:16 pm

There are multiple ways to measure cost. For me, I'm less concerned about minimizing out of pocket expense as I am to get equipment that actually *works*. If it doesn't work, it's false economy. Before I got the Iogear KVM, I tested another such device. It didn't work in my environment. So I RMA'd it and kept looking. The 4-port Iogear has been solidly reliable for about 4 years now. The Trendnet 8-port VGA/PS-2 has been in use for about 20 years. That sort of reliability offsets a great deal of cost (figure it on a dollars/year basis...).

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sconemad
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Re: KVM Switches Pi's and other

Mon Jan 28, 2019 12:16 pm

rec9140 wrote:
Sun Jan 27, 2019 5:17 pm
X is NOT used 99.99999% of the time so VNC is not an option. These units are tasked with heavy loads and X running without need is wasted resources.. I only need X every now and then, and same with actual local use, but occasionally its needed instead of ssh and its mostly locally.
The RealVNC service mode server will work without X running, provided you enable "Direct capture mode" (in Options > Troubleshooting) so it may be a possibility.

If you can't get to the UI, then simply add a line saying "CaptureTech=raspi" to the file /root/.vnc/config.d/vncserver-x11

LTolledo
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Re: KVM Switches Pi's and other

Mon Jan 28, 2019 9:53 pm

Looked at the Iogear HDMI KVM. I can only source a 2-channel version here.
And as mentioned by fellow members, its quite expensive, more than thrice the price of an RPi3B+.

Currently the solution am using is [3-port HDMI switcher + 2-port USB switcher], the sum of both cost a bit more or less than RPi3B+.

After a few more searches I've stumbled upon a 4-port 4K HDMI KVM priced just right (I think)... may try to get one by weekend...
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"

W. H. Heydt
Posts: 10881
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: KVM Switches Pi's and other

Mon Jan 28, 2019 11:50 pm

LTolledo wrote:
Mon Jan 28, 2019 9:53 pm
Looked at the Iogear HDMI KVM. I can only source a 2-channel version here.
And as mentioned by fellow members, its quite expensive, more than thrice the price of an RPi3B+.

Currently the solution am using is [3-port HDMI switcher + 2-port USB switcher], the sum of both cost a bit more or less than RPi3B+.

After a few more searches I've stumbled upon a 4-port 4K HDMI KVM priced just right (I think)... may try to get one by weekend...
If it works, post a link.

rec9140
Posts: 33
Joined: Mon Sep 12, 2011 5:29 pm
Contact: Website

Re: KVM Switches Pi's and other

Tue Jan 29, 2019 1:40 am

W. H. Heydt wrote:
Sun Jan 27, 2019 6:00 pm
I'm using an Iogear 4-port Miniview. It's an HDMI/USB KVM.
Link?
W. H. Heydt wrote:
Sun Jan 27, 2019 6:00 pm
The way to handle your monitor with DVI input is to use HDMI cables between the Pis and the KVM and then use your HDMI to DVI cable on the shared output to the monitor.
That was/is sort of the plan, but I expect issues with the KVM and/or Pi's being fickle about that. JUst the nature of things...
W. H. Heydt wrote:
Sun Jan 27, 2019 6:00 pm
Or, of course, you could find a KVM switch that uses DVI and use HDMI to DVI cables from Pis to the switch and then a straight DVI cable to your monitor.
I found an IO Gear one like that.

https://www.iogear.com/product/GCS1104/

I like it..
W. H. Heydt wrote:
Sun Jan 27, 2019 6:00 pm

The big problem is that HDMI KVM switches are rather more expensive than VGA ones, and I fear it's not going to get any better, due to the increased bandwidth needed because 4K displays are becoming popular (and one can only wonder what will happen if/when 8K goes mainstream...).
2160p and 4096p won't be main stream with me for a long time. I have a 2160p TV but little to no content for it, and wouldn't notice the difference between it and 720p which 90% of the content is... I don't DBS or CATV or new fangled IPTV, and suffice it to say this forum will most egregiously be offended by my method. And I don't have anything that could output 2160p if I wanted it to any way. :)
W. H. Heydt wrote:
Sun Jan 27, 2019 6:00 pm
Future plan is "reverse" part of that. As newer systems output HDMI and/or DVI, but not VGA, I want to get an 8-port HDMI/USB KVM to which I can slave on individual ports both the VGA/PS-2 KVM (using a VGA to HDMI converter) and the 4-port HDMI/USB KVM.
Well things are very unlikely to progress too far with me.. Pi's are the only thing on PC's that have HDMI as a primary output... I build everything else and always get a card with DVI and VGA out. The TV's are the only thing that have HDMI in's around here. and they are all purchased with VGA or DVI' ins as well to ensure compatibility in my realm.

W. H. Heydt wrote:
Sun Jan 27, 2019 6:00 pm
So...Yes. Pis work just fine through KVM switches.
My concern is more

1) Using the HDMI to DVI and the PI's and/or KVM and/or the monitor having a hissy fit and not playing nice with this

2) COST.. This convenience and ease is about 2x my desired price...

So others with HDMI and/or DVI units link away! Maybe I find a deal on something I am not seeing right now.

W. H. Heydt
Posts: 10881
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: KVM Switches Pi's and other

Tue Jan 29, 2019 2:47 am

rec9140 wrote:
Tue Jan 29, 2019 1:40 am
W. H. Heydt wrote:
Sun Jan 27, 2019 6:00 pm
So...Yes. Pis work just fine through KVM switches.
My concern is more

1) Using the HDMI to DVI and the PI's and/or KVM and/or the monitor having a hissy fit and not playing nice with this
I use HDMI to DVI cables with Pis all the time because I only have one monitor that ever gets used with a Pi that has an HDMI port (it also has DVI and VGA). I use Pis to run registration for an 1800 person convention (it's coming up in about 3 weeks...Yikes!). I set up 5 Pis and every one of them is connected using an HDMI to DVI cable and I never have any trouble.
2) COST.. This convenience and ease is about 2x my desired price...
Welcome the world of semi-pro to professional equipment. (A KVM switch isn't a normal "household" item.)
So others with HDMI and/or DVI units link away! Maybe I find a deal on something I am not seeing right now.
One minor point that may be of use... In config.txt, set the flag to force HDMI.

hippy
Posts: 5935
Joined: Fri Sep 09, 2011 10:34 pm
Location: UK

Re: KVM Switches Pi's and other

Tue Jan 29, 2019 11:11 am

rec9140 wrote:
Tue Jan 29, 2019 1:40 am
My concern is more

1) Using the HDMI to DVI and the PI's and/or KVM and/or the monitor having a hissy fit and not playing nice with this
Pi's work fine through HDMI cables, into DVI adapters, and into DVI monitors, so there's no reason to anticipate that putting a HDMI selector or KVM in the HDMI cable path would stop anything working.

LTolledo
Posts: 1942
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Re: KVM Switches Pi's and other

Thu Jan 31, 2019 11:25 am

W. H. Heydt wrote:
Mon Jan 28, 2019 11:50 pm
If it works, post a link.
Just ordered it, a 4-port 4K HDMI KVM switch, 4 USB cables included, no HDMI cables
...its about USD 80.00 from Amazon
added a pair of HDMI cables with that order....

... will arrive and test by the weekend... and post afterwards...
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"

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