Wombat Diet

I just installed a KVM switch to share a Keyboard, Video and Mouse among several computers. Specifically, an ATEN CS1734B, a 4 port switch that also permits sharing of USB and audio peripherals.

Ahh, your Hitler box

said the lady of the house when I described it. A Master of The Universe (MOTU) I could understand, though I am not such an exalted person, but Hitler?

My old KVM switch, which she seemed to have forgotten about (or perhaps never noticed), had died en route from the tropics. As result, I have had two keyboards, mice and monitors on my desk for my Vista and Linux computers for the least year or so.

On the left: the CS1734B switch as shown on ATEN’s web site. It’s hard to tell how big it is from this photograph. It’s actually quite a small box (21×8x4.5cm).

The reality on your desk is slightly different.

It was not immediately clear from the diagrams on ATEN’s website how the switch really worked.

Some switches that handle USB have USB ports on the back for each computer, but not this one. Finally, it dawned on me that the yellow ports on the back were not standard monitor ports, but proprietary combination VGA monitor + USB ports.

It’s obvious to ATEN, but to the prospective customer trying to make sense of the specifications of these devices it would be helpful to point this out.

ATEN’s website has a helpful comparison chart that allows you to quickly focus on the few of dozens of available models that might be of interest. Unfortunately, it doesn’t include new models already on sale, which is inexcusable.

Nevertheless, my advice if you need such a box for personal use is to start with ATEN’s site. I say this having looked at just about all the alternatives. Check the new products as well as the table.

What finally pushed me into into buying a new switch was replacing Xubuntu desktop on my linux server with Ubuntu desktop. They’re just different interfaces. Xubuntu’s had worked well but I decided that I preferred not to do without the network Places on the top menu. Xubuntu just doesn’t have it.

This minor decision led to unexpected consequences. When the server was put back in the cupboard in the hall afterwards I couldn’t get remote control over it again (using UltraVNC, my preferred solution). It worked on my desk, then failed in the cupboard, twice.

Arrgh! How often is a solution a new problem?

I subsequently found that Ubuntu desktop reverts to a low resolution graphics mode when there’s no monitor attached and that when this happened I couldn’t connect.

I didn’t really mind, the utility cupboard had seemed a little too warm anyway (there’s some storage and a wireless access point there already). No doubt there’s another solution, but I had a spare shelf under my Vista PC, where my Windows XP / Ubuntu dual boot PC used to live before it expired. The replacement Linux (Ubuntu desktop) PC doesn’t quite fit there and so it lives on the window sill behind my desk.

With the cupboard door closed these two boxes are quiet. Not silent, as I’d like, but tolerable (the back of the cupboard is open).

In principle, all I had to do was connect everything up then I could switch the audio, video, USB devices (printer, scanner, webcam etc.) and KVM — so that I could listen to music on one system, scan documents on another and print on another, or so the manual would like to have you believe.

All you ever really want to do is just avoid plugging and unplugging stuff all the time. Funny how they don’t mention that.

Tired of groveling behind your desk?

People are never shown on their bellies getting dusy in ads for these boxes, but in fact one of their chief benefits is that you end up not doing it so often.

The manual says to upgrade the firmware from a computer not connected to the KVM ports — because all of these should be shut down first. A cable is helpfully included with an audio type connector at one end and a DB9 serial connector at the other. Unfortunately, my only computer with a serial port was running Linux and the software was only available in a Windows version. I tried and failed to use a USB to serial converter that I had in a drawer, and I then discovered that the ATEN box lacked a reset switch.

Needless to say, I had not shut everything down before I selected Firmware Upgrade on the onscreen menu; I expected another prompt to confirm. Instead the device just started flashing its LEDs at me as it waited for the new firmware to arrive, and it seemed willing to wait forever (would a timeout hurt?). All the computers attached were now unavailable, as you’d expect, and I had to disconnect everything to get past this. Happily I didn’t have to open the box and set a jumper to reinstall the default firmware.

This was just a small warm up for the fun I had with Vista.

My plan was to keep my main monitor (a 22″ Samsung 225BW) on Vista all the time, and have my 2nd monitor (a 17″ Samsung 181T) switch between systems.

Both monitors have analog and digital inputs. Unfortunately, they are not switchable. Both inputs can be used, but only one at a time. To switch connections you’d have to unplug and replug cables, which is impractical as well as inconvenient as the cables connect below the screens.

While there are switches on the market for sharing pairs of screens they’re designed for analog or digital connections and not one of each. Somehow, I find this surprising. Surely, a lot of people have one new monitor and older analog one?

Anyway, the “fun” began when I switched monitor number two to an analog connection via the ATEN box. I had previously used it as a 2nd monitor on Vista, but only when my other PC was switched off.

Vista decided that the smaller monitor was monitor number 1 and it couldn’t be persuaded otherwise, it also switched to a generic driver that resulted in a less crisp image. I had no problem making the larger monitor the main one, and extending the display onto the second, but why I couldn’t persuade Vista to make it number 1 I don’t know.

I tried swapping monitor ports on the Vista box, only to find that they were different versions of DVI, and that with one combination nothing was visible (on the Vista PC both monitors are connected via DVI, but with an adapter to convert to VGA in case of the 2nd).

I will draw a veil over the rest. Suffice it to say that Vista was dictatorial and tempermental.

I did end up with what I wanted, more or less.

Here’s the onscreen display (activated by pressing ScrollLock twice) showing two devices powered up, with the USB and audio connected to Vista and with keyboard video and mouse connected to the Ubuntu server. (Click on it for a bigger image).

In addition to using the onscreen display it’s also possible to switch connections using the front panel of the box or, less easily, with a hotkey sequence.

My old switch, couldn’t cope with a wireless mouse. This one does without any problem, and can also deal with Mac and Sun keyboards as well.

With an adapter cable it’s possible to use PS/2 devices (keyboard, mouse) or to connect a PC with PS/2 min-MIN ports. The illustration on the ATEN’s web site suggests that you can connect two such devices but only one such cable is included.

The audio ports on the front panel of the switch override those on the rear. This is not mentioned explicitly on ATEN’s web site (unless I missed it) and is actually quite desirable; it makes plugging in a headset for a Skype call, say, quite convenient.

One thing I was a little disappointed to find didn’t work was running a remote desktop session to a linux box in full screen mode on the second monitor. It worked ok in less than full screen mode, but switching to full screen caused the image to disappear. However, I’m sure it’s a Vista problem.

The confounding factor in making devices like this is the number of different interfaces used on the PC. It makes it necessary to produce permutations of features, and it’s still hard to find something perfect. This box will begin to be obsolete as soon as USB 3.0 arrives. Isn’t it about time that computers had an optional KVM port to run everything over an Ethernet cable, or do we have to wait for Wireless USB?

Meanwhile, if this switch had

• DVI input and output ports and a programmable ability to use analog or digital output (this would permit a dual input monitor to be used with several different systems, in particular 1 digital system and several with analog outputs) and
• An alternative to the serial interface for updating the firmware

I’d give it 10 out of 10. For now this ATEN gets 8 out of 10.

And I get a bit of desk back.

Tags: linux, Technology, vista