MOTM

--- In motm@yahoogroups.com, "Paul Schreiber" wrote:
> This is probably "old hat" to many computer geeks, but I just
> discovered the neatest gadget for my office.
> 
> It's called a KVM switch: Keyboard, Video and Mouse. It allows 1
> keyboard/monitor/mouse to control up to 'n' PCs without swapping
> cables...

We have the fancy $1000 model "at the office"  It is an Avocent 
(Cybex) product that connects 8 PCs on one side of the switch with two 
sets of display/keyboard/mice on the other side.  One "terminal" 
(display, keyboard, mouse) is in the equipment rack with the KVM 
switch and all the attached PCs.  The other "terminal" is remote via 
CAT5 cable!!!  The KVM switch actually sends the analog RGB signals 
over 3 of the twisted pairs in a CAT5 with the 4th pair used for the 
PS2 (keyboard/mouse) signaling.  Switching between connected computers 
is done with the keyboard.  A magic key sequence (something like 
pressing "print screen" twice) brings up an on screen video overlay 
with a list of machine names to choose from.

I'm sure these products work great in a facility with a really good 
grounding system but in our "office" we had problems with the video 
going in and out of sync at the remote terminal.  My first thought was 
to lift the ground on the remote CRT which improved but did not 
eliminate the video sync problem.  My final solution was to run a #10 
ground wire along with the CAT5 cable to force the remote terminal to 
a close enough ground potential.  Works great now!  It is somewhat 
amazing to me that high resolution (high frequency) analog video can 
be run across a hundred feet of unshielded twisted pair and still have 
a nice sharp image at the remote terminal!


The first place I saw a really fancy KVM system like this was at a big 
(conglomerate / multi-station) radio broadcast facility.  They had all 
of their computer equipment in a centralized equipment room (probably 
50 to 100 computers, PCs and Macs) and all of these went through a 
monster Cybex KVM switch out to many remote terminals.  They claimed 
this solved numerous problems such as 1) elimination of machine (fan) 
noise in the "on air" studios and production rooms, 2) expensive 
machines such as ProTools could be shared between rooms, 3) equipment 
maintenance was centralized.  (Don't need to kick anyone out of a 
studio or production room to fix a dead power supply in a PC or 
whatever.)

They had a similar monster switching system that routed audio between 
different rooms.  I can't remember who made the audio switch but I do 
remember poking my nose into the card frame on this thing to see who 
made the audio crosspoint switching chips.  (Analog Devices)



> Mine is a Linksys 2-port model ProConnect, for a staggering $29
> from buy.com (digress: Linksys is the MOTM of the computer world.
> I buy ONLY their stuff, and I have ~8 various things of theirs and
> all work FLAWLESSLY).

I think you are selling MOTM short.

I know a few "computer knowledgeable" guys who recommend Linksys 
products for budget computer networks but acknowledge that Linksys is 
something like the best of the worst.  I'm sure products like the KVM, 
Ethernet hubs, etc work fine.  However when there is a significant 
amount of software (firmware) involved (in products like the Linksys 
Cable/DSL routers) that is where you sometimes run into problems.  
Weird stuff like Internet access gets slower and slower and eventually 
stops.  If impatient, just press the secret reset button on the 
Linksys router.  Or, if you like, just wait a few more minutes and the 
hardware watchdog will press the reset button for you ;)


seth