To tell you why I use a KVM (Keyboard-Video-Mouse)
switch, let me begin by describing my computer setup, where I have been,
where I am now and where I am going. Until about 3 years ago I had a fairly
standard setup, I had a single computer and I connected to Texas.net and
the Internet with a standard modem using a second telephone line. I was
happy with Texas.net. If I had trouble I called and they told me what to
and behold everything worked again. Except on rainy days I usually got
indicated speeds of 30 to 40 kilobits per second. I was happy. The set
up worked, and I did not know about real access speed. I was an innocent
Then came DSL via SBC, although I think it was Southwestern Bell then.
Behold the installer came on time, did the hook up and the self install
box came in the mail. Because I am within a mile of the local office I
got a 1.5 megabit per second connection which in the real world works out
to receiving about 125,000 to 150,000 bytes per second. Because I was worried
about the nasties inherent in an always on, high speed internet connection
I got a Lynksys hardware firewall/router. Life was good. I was safe. I
still kept Texas.net as my Internet service provider and again I was happy,
faster but still happy. Then I noticed that having one computer connected
to the Internet translated into my not being able to use the computer all
the time. I had to share my computer! Thus began the local Ethernet wiring
era. I linked all the computers in my office. Then I ran cable to my daughters
bedroom for her computer. My wife liked that so much that I got to run
wire to her computer in the spare bedroom. Ethernet wiring with bulk wire
and punch down blocks or with pre-made extension cable is really easy,
except for hanging upside down under the roof with the ladder sliding away
while trying to secure the wire. I also learned to measure the length of
wire needed carefully, accounting for each section, allowing for curves,
then when you have the final total accurate amount you know you need, add
an additional 50%. Trust me this is a good idea. In fact this is a very
good idea, consider hanging upside down under the roof, etc., first to
take out the just too-short cable, and then again to install the very slightly
Then SBC and Texas.net agreed to disagree. No problem, said I, I will
just switch to SBC as my ISP, what do you mean you can not do that, you
have to disconnect me for a week or two, and then perhaps reconnect me
and charge me for a full install. But I am already wired to SBC, it can
not be that hard to change…
And so began the Time-Warner Roadrunner cable modem era. The download
speed is a little faster than DSL, probably 200,000 to 250,000 bytes per
second. In practice this only makes a difference when downloading a whole
CD or set of CD, which we will return to later.
Anyway this was my basic setup and its history. I used the standard
Win98SE and Win2000 operating systems, with Office and Outlook and a current
version of Internet Explorer. I do the bug fixes and patches regularly.
As I mentioned previously I have a Lynksys hardware firewall, and I use
the free version of Zone Alarm as a software firewall. But I do share access
to printers and files with in my network. I have run Norton Utilities since
the DOS days and Norton Antivirus (with current virus identification files)
since it was available. I also do not allow Java to run and have turned
off the Word macro capability.
I really thought that this would be safe, and before the past year I
think that this setup was safe. However, it is not safe now. The combination
of Windows, Internet Explorer and Outlook exposes your computer to just
too much dangerous material.
I downloaded (love that high speed) a free copy of Pest Patrol and was
horrified about the amount of predatory files on my computer, including
keystroke loggers. I was so impressed and frightened that I actually bought
a copy. I have also added Web Washer to (help) (I hope) prevent pop up
ads, Start Up Cop (PC-Magazines utilities) to keep the start up programs
to those I wanted, Ad-aware, and Big Fix to keep track of bug fixes. Except
for BigFix, which I have not decided how I feel about yet, these are all
very useful programs.
Should it be this hard and dangerous to just use a computer? Now I do
not have anything that is sensitive or even very private on my computer
but I hate the idea of being so vulnerable. My wife keeps her grades on
her computer so to some extent we have a privacy issue. If I had anything
of commercial importance I would be very concerned.
Long term, I think that abandoning the entire windows operating system
and programs such as Outlook and Internet Explorer may be necessary, and
I can see going to a Unix derivative (e.g. a free Linux). But in the short
course what I am doing is using two computers. The computer that surfs
the internet and gets mail is my old AMD 350 with a 6 GB hard disk with
a very minimal install. Everything else, such as this manuscript is on
my main computer which usually does not access the internet. In fact, if
I were just a little more cautious I would disconnect my main computer
from my home network entirely.
So division of computer tasks is the first big reason for using a KVM.
You can use two (or more) computers with a single monitor, keyboard and
mouse. With an electronic switching KVM you can switch between monitors
without having to turn everything off. Yes, I tried using a basic mechanical
switch and it was not very satisfactory. Even less satisfactory was using
two keyboards for two computers. This arrangement took too much room and
I kept typing on the wrong keyboard. I am not so sure about switching mice.
If you have multiple monitors on one computer having instead access with
a mouse is nice but in general the KVM switches are successful because
they are so useful.
Other reasons for using a KVM with a home computer network is to get
the resource hogs, like AOL Instant Messenger, off your working machine.
Actually, I consider AOL IM both a recourse hog and a security hole but
I still have to use it as both my wife and my daughter are fans.
Finally, a KVM lets you control multiple computers so that you can allocate
time wasting process, such as downloading and burning a Linux CD set to
an other computer leaving the main unit free for use. Also, if you program
you can send program and error messages to the second unit, without messing
up your code running a debugger. Finally, you can experiment with passing
out sections of long programs among multiple CPU, which can make slow code
run much faster.
KVM switches are generally either 2 or 4 port meaning that they connect
to 2 or 4 computers, but much larger 8 port units are available. Some units
are also able to be connected to each other so that nine of the 8 port
units could connect to 64 computers. This is probably excessive for the
average home user. Even I do not have 64 computers.
Prices range from about $50 to several hundred dollars, depending on
the unit and where you get it.
As well as the Avocet Switch View -MP (4 port) this article describes
I have been using a Smart View 2 port KVM which essentially makes the exactly
opposite choice in every design decision, making the two units an interesting
contrast. The Avocet connects to four computers and the Smart View to only
The Avocet is much larger (1.9” x 8.1” x 11” , HWD). The Switch View
is much smaller at 1.8” x 5” x 2.8”. A KVM has to be fairly large to allow
all the wiring and rather hefty to keep from sliding on a desk. I have
not had a problem with the Smart View sliding but it is stabilized by the
paper avalanche on my desk. You have to realize that the total weight of
cables will probably be greater than the KVM. Both the Smart View and the
Avocet have soft gummy feet to keep them from sliding and the larger Avocet
has mounting holes as well, which is appropriate to its larger size. I
have the feeling that the Avocet would be happy in a production, commercial
environment where its greater flexibility and “quality” would be appropriate.
The Avocet Switch View came with both an external power supply and 4
cables. Two of the cables were DB25 to VGA plus PS2 for mouse and PS2 for
keyboard. The other two cables were DB25 to VGA plus a single USB connector.
The power supply looks to be a nice little mini-switching supply that puts
out 2.5 amps at 5 volts while the switch box itself is labeled as requiring
only 1 amp at 5 volts. This is one of the places where extra headroom will
give cooler running and probably better long term life. Also the PS is
not a cheap wall wart that clogs up the outlet box but comes with its own
power cord. By the way if you have a bad case of wall warts Googlegear
has 6” extension cords to keep wall warts from blocking electrical outlets.
The Smart View does not come with either cables or a power supply. The
Smart View also comes only with PS2 ports for mouse and keyboard and VGA
connectors. Now which is better. I like the power supply for the Avocet,
the idea of stealing power from the PS2 connectors seems a little iffy.
The Smart View has a power jack but I never added the 9 volt supply.
Because the Avocet supplied the cables, especially the VGA section they
can specify the video resolution to 1600 x 1200 at 85 Hz. I do not know
the video resolution of the Smart View, but it would depend, in part, on
the cables used. The Avocet cables are a useful 8 feet long and are a single
cable to the computer which usefully reduces the cable tangle. If you do
have a severe cable tangle Velcro straps (ca $1 each) help or if you are
as thrifty (in fact cheap) as I am I would recommend a roll of Johnson
and Johnson self sticky tape sold in the bandage section of drug stores.
The tape is a little stretchy will stick only to itself and can be reused.
On the other hand the Avocet cables may be expensive (a cheaper source
of Avocet cables is www.KVMs.com
and may have to be ordered only from Avocet or its dealers. [check altex]
Now that I have used both kinds (multiple cheap cables, single expensive
cable) I tend to favor the single cable for the resulting decrease in cable
clutter, although I would not pay Avocet’s list price.
For PC’s, the console connections of both KVM’s are the same, PS2 for
keyboard and mouse and a 15 pin standard VGA connector. However, the Avocet
has the provision for connecting to a Sun as well. In fact being able to
connect a PC keyboard and mouse to a Sun may be a deciding factor in selecting
The Avocet uses a DB25 connector at the switch end which is terminated
with a 15 pin standard VGA connector and either a set of PS2 plugs for
keyboard and mouse or a single USB connector.
The Smart View is simple: push the button to switch unit and the button
takes a fraction of a second to respond. The Avocent Switch View on the
other hand has both a single button to go to the next computer and a set
of keyboard commands to go to any computer or to scan at variable rates
among computers. The Avocent can also resynchronize with the mouse if the
mouse gets lost while changing computers.
In general, cheap 2-port KVM switches are in the $50 range (without
cables) and 4 port models in the $100 area. Cables generally run $20 to
$50 depending on where you buy them and their quality.
In conclusion, the Avocent Switch View is a very nice, if a little expensive,
product. Perhaps it is geared more to a commercial environment where just
being nice to work with and probably of higher quality and more dependable
is worth the extra money. Having both I will be using the Avocent Switch
View . Of course, if you have a mixture of PC’s and Sun’s there is no question
that the Avocet is a better buy.