Using KVM to control multi computers
 

A "KVM switch" (KVM= keyboard, video/visual, mouse), lets you control multiple computers with a single monitor, mouse and keyboard. Some of the better ones even include a printer USB hub and audio jacks.

Home users usually only have a single computer. But many techs, videographers/photographers, and similar computer-saturated careers have at least 2-3 computers in their office. Many of them have a desktop and a laptop, sometimes several desktops.

This post is being made in reply to a phone call. I needed some time to track down the perfect KVM for him.

The person in question has a legacy ATI All In Wonder capture card that does great -- and he's quite happy with. However, the computer running the card is a bit old, and no longer runs the latest software as fast as it could. Even something as simple as Office 2007 or Firefox 3.5 can really suck up the CPU and RAM from an outdated computer.

The solution was to keep the old computer on the floor, under the desk, relegated PURELY to capturing video, and then adding a new computer on the desk. The new computer features the latest in whiz-bang speeds, including the PCI express card bus, which the ATI AIW card cannot use. However, rather than suffer through a desk with multi monitor and keyboards, a simple KVM will solve the trick.

This particular KVM model works well, as it has buttons on-box (no crazy monkey-claw keyboard commands required), passes audio, and works with USB keyboard and mouse. I use these myself, due to their high quality. The video has high bandwidth VGA, so the image quality is not degraded -- a common problem of KVMs on modern high-resolution LCDs.

Get the AirLink USB KVM with Audio @ http://www.amazon.com/gp/redirect.ht...reative=390957

Some people will refer to the KVM as a "switch box", but it does more than simply switch the signals -- it keeps the signal "alive" in each computer. Remember that computers know when a mouse and keyboard has been unplugged, often with undesirable consequences (system lockups, mostly).

Sorry to dig up this topic, but I'm in the same situation as that guy on the phone actually.

So I wondered if there are any affordable 2-port switches that allow for the connection of an extra usb-device like a printer/ external hdd to the KVM?

Some of what you want isn't technically possible. But there are workarounds.
I'll update this post with more in several hours, or tomorrow.

Hard drives cannot connect via a KVM, because drives are not "hot swappable" in that manner. If you want to share a single hard drive amongst many computers, you must either share it from it's "master" or "host" computer, or simple used network-attached storage (NAS). Gigabit ethernet networks are best, when sharing hard drives in this way.

Printers are also not really "hot swappable" like this, and each new "turn of the dial" (so to speak) between computers would re-trigger auto detection of new hardware. Much like hard drives, printers must either be shared from a single computer, or put onto the network via ethernet connection. A printer without native ethernet/networking can generally be "converted" into a network printer using a low-cost hardware adapter (a "print server").

For a long time, the Airlink KVM from the first post was the only real contender as the best KVM. Now Trendnet has one, too, which does audio, USB1 connections (mouse+keyboard), and high bandwidth VGA. It's about $20-25 cheaper than the Airlink, but I still give the Airlink my #1 recommendation, as I own several of them, and have had years of success with them.

TRENDnet 4-Port USB KVM Switch Kit with Audio (Includes 4x KVM Cables)
$50 @ http://www.amazon.com/gp/product/B00...SIN=B000M5VXVS

TRENDnet 2-Port USB KVM Switch Kit with Audio (Includes 2x KVM Cables) TK-209K (Blue)
$29 @ http://www.amazon.com/gp/product/B00...SIN=B000L4D42Q

Cellvision Systems PRS-301U, 1-Port USB Print Server - Share Your USB Printer on a 10/100 Ethernet Network!
$20 @ http://www.amazon.com/gp/product/B00...SIN=B004BVJPL4
(I may soon buy this cheap printer server for my own needs.)

Other print servers to choose from, at about double the price:
$38 and up @ http://www.amazon.com/gp/redirect.ht...reative=390957

If you want some suggestions for a NAS, let me know. But honestly, I prefer to just share hard drives from the computers. Long-term, it's far cheaper. The main computer here is basically a server with about 10TB of drive space (some of which are powered off when not needed, being on-site backup/recovery drives). Some of the others simply have "shared" folders (custom location shares, not the BS default location desired by Windows or OS X).

Aside from KVM-over-IP (expensive, not easy to work with), these are really your only options.

The Trendnet sounds like a nice and affordable solution, and that printer network device is certainly something to keep in mind if it turns out it's not just for the time being that I need a printer on both computers. As for the external hdd's, sharing is a good work around yes (it also helps I don't need them all the time and eventually could do with only one pc connected to such devices). Just wondered if it was possible to do it simpler.

One question though, from I've understood these devices are USB-powered, but does that mean they can be connected to the pc's through two USB cables and draw power from either pc, or does one need to be on constantly?

Any one computer powers the Airlink.

Related trivia: I have one system that sends power through the USB ports, even when the system is "off" -- so the KVM is always on, for as long as the computer is receiving electricity from the wall outlet. It's a "power vampire" that you always hear about from conservation and "green" groups. So anytime I'm not going to use it for several days or longer, I have to unplug it from that system's USB. Then it cuts off fully. Otherwise it's on, with a blinking light. (The light on the KVM will blink when it can't find any mouse or keyboard input. Because the system is off, it gets no signal, and therefore blinks non-stop. Lights are solid when keyboard/mouse is connected and "seen" by the KVM.) The other four-system subnets have systems that fully power off, so the Airlinks turn off when the systems are shutdown.