One Keyboard, Mouse, and Monitor To Rule (Well, Run) Them All
- What Is a KVM Switch?
- Why Do You Need a KVM?
- Choosing Your KVM
- Installing Your KVM
- A Few Notes
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When you got a DVD player to go with your VCR, you didn’t feel the need for an additional television next to the first one, did you? Of course not. (A better one, maybe.)
Similarly, if you’ve got more than one computer, you wouldn’t want to clutter up your desk with a bunch of keyboards, video monitors, and mice, one for each, would you? Well, you might want to have multiple monitors for one system, or to keep eyes on several at the same time, but that’s a different question. (See my upcoming article on how monitors multiply display turf.)
If you got a notebook computer, wouldn’t it be convenient to use your existing keyboard, display, and mouse when at your desk? Of course, you could do this by constantly moving and switching the connecting cables around.
Or you could get a KVM switch.
Here’s some thoughts and advice on why and how.
What Is a KVM Switch?
In case you haven’t already guessed, KVM stands for Keyboard Video Mouse, and the switch part of the name is there because a KVM switch lets you connect a bunch of computers and select which one the keyboard, video, and mouse currently control. You plug your mouse (or other pointing device), keyboard, and display into the KVM, and run cables from the KVM switch to each computer. (Of course, you could also do this in software, with a remote-access program such as VNC, GoToMyPC, etc., assuming that your computers are networked together. But this means having the accessing computer turned on, assumes they’ll all handle the appropriate software...and breaches any "air firewalls" you may want to maintain, especially if you’re testing funky software.)
KVM switches have been around for decades. And they’re still popular; indeed, as companies look to ways for people to access and manage remote systems, IP/KVMs—KVM switches that can connect over IP networks, rather than through direct cables—are a popular solution.
How popular? KVMs account for about a quarter of remote desktop management (not counting console extenders or software solutions), according to Chad Hart and Spyros Photopoulos, analysts at Venture Development Corporation, an independent technology market research and strategy consulting firm.
In their June 2005 report, "KVM " Console Switch Solutions: Global Market Demand Analysis," they estimated the 2005 worldwide shipments of KVM switches and serial console servers at $118.3 million, with personal/desktop KVMs accounting for about 30% of the total, and predict that the worldwide market for KVM switches will "exceed $888 million by 2007, a CAGR [compound annual growth rate] of 12.5% (2004–2007)."
About 70% of KVMs sold, estimates Photopoulos, are personal/desktop units. But they represent only a fraction of total revenues, because they cost so much less than company-size devices. He says that about 1.1 million desktop KVMs were sold in 2004, and estimates a total installed base of KVMs today at somewhere between 10 and 20 million.
There are plenty of KVM vendors—a quick check at Newegg.com shows about two dozen—including APC, Aten, Belkin, D-Link, IOGEAR, Linksys, Raritan, and Rose.
Entry-level "consumer" KVM switches have come down to prices that anybody can afford. For switching between two computers, two-port KVMs from companies like Belkin and IOGEAR start around 40 bucks (if you watch the sales, you may find one for as little as $20 or $30), including cables, a USB connector for mouse and keyboard, and possibly audio in and out cables—plus video, of course.
For example, at the time of writing (mid-November), I saw a sale price for IOGEAR’s two-port MiniView Micro KVM Switch at KVM Switches Online for a nickel shy of $30—that’s 10 bucks off—and Newegg.com shows several KVMs in the $15–20 range.
"The basic low-cost no-frills unit is usually two-port, with cables attached (bonded) to the KVM, and has either PS2 or USB connectors for the mouse and keyboard," notes Keith Renty, a product manager at IOGEAR.
Low-end KVMs may feel like a large handheld switch. The next step up, Renty says, may look more like desktop devices and have detachable cables. This step up also may include ports for audio peripherals (speakers, possibly a microphone).
For a KVM that connects more computers, such as a four- or eight-port KVM, and or other bells and whistles, expect to pay more, in the $200–400 dollar range.
In addition to more ports, newish bells and whistles can include USB 2.0 ports for peripherals—printers, flash drives, external hard drives, label makers, burners, and so on. The USB hub ports should support independent peripheral sharing, meaning that switching the K, V, and M to another computer doesn’t inherently switch the USB hub ports. (Check for this feature before you buy!) For example, if something’s still printing or saving to a hard drive from computer A, your peripherals isn’t disconnected.
Other possible features: PS2 and USB mouse/keyboard ports, a four-port Ethernet switch, even the ability to handle two monitors—assuming that your computers are dual-head.
Beyond the scope of a desktop user (or this article). there are higher-end KVMs, with 8, 16 or dozens of ports, rack-mountable, possibly able to work over IP networks (IP/KVM), costing from $1,000–3,000, but these are intended for businesses supporting multiple users accessing perhaps dozens of systems, or located at a number of sites.
The original KVM switches were mechanical, using rotary switches. I’ve been using one for many years, and only just retired it. A mechanical rotary KVM is inexpensive. However, as careful reading of documentation cautions, there’s a possibility that power blips may leak across as you turn the dial. My solution was to turn computer and monitor off before switching, which was safe but far from useful. A better (and more expensive) type of KVM is an electrical "break-and-make" KVM, which "breaks" the current connection and then makes the new one, avoiding the electrical leakage problem.
Another advantage of electronic versus mechanical KVMs is that the electronic versions can—and need to—include port emulation circuitry so that the other computers still "think" they have a keyboard and mouse connected.
When you start shopping, you’ll see a spread of prices for what seem to be similar-featured devices. Why? According to KVM Switches Online’s FAQ, "As in all products, some have more options. Some switches offer USB sharing, On Screen Display (OSD), audio support, port emulation, multiplatform capability, built-in conversion, come with cables, and have power supplies. Whether you will need or want these features is up to you."