KVM problem

Archived from groups: alt.comp.hardware.homebuilt (More info?)

Hope somebody can help here....

Have been using a Belkin KVM switch with built in cabling
http://www.dabs.com/uk/Search2/Product+Details.htm?quicklinx=2TTD&searchphrase=kvm
for 14 months with no problems initially with a Logitech Marble
trackball with a PS2 plug and then went onto a Microsoft Trackball
Optical with a USB plug and the supplied USB -> PS2 adapter with no
problems.

The switch died and I managed to pick up a D-Link DKVM-2
http://www.expansys.com/product.asp?code=105699&partner=register
which looks like a far better quality box to me, very heavy and
separately powered but I seemed to have a problem that when I switch
from one computer to other the mouse is completely frozen, while first
is fine. If I press the sleep key, put the comp into sleep mode then
wake it up again the mouse wakes up so it's not a hardware problem.

I switched off the computers, unplugged the KWM and started it all up
again and the same thing happened... but the computers were switched
round, the one the previous had functioned fine now had the mouse
freezing problem and the previously problematical one was now fine.

I tried my old Logitech PS2 was fine although it was occasionally
locking up on both machines.

I put in the Microsoft back in and thought I'll just have to live with
it.... and it now works fine - for how long I don't know.

Are there any known problems with KVM switch's? I'm running XP on both
machines.

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ButIstillneedtoknowwhat'sinthere!Thekeytoanysecurity
systemishowit'sdesigned!Thatdependsonwhyitwasdesigned!
Ihavetoknowwhatwhoeverdesigneditwastryingtoprotect!
(Blakes 7, City on the Edge of the World - Vila in typical panic mode)

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4 answers Last reply
More about problem
  1. Archived from groups: alt.comp.hardware.homebuilt (More info?)

    On Sun, 12 Sep 2004 21:41:50 +0100, Luke Curtis
    <mfll78@dsl.pipex.com> wrote:

    >Hope somebody can help here....
    >
    >Have been using a Belkin KVM switch with built in cabling
    >http://www.dabs.com/uk/Search2/Product+Details.htm?quicklinx=2TTD&searchphrase=kvm
    >for 14 months with no problems initially with a Logitech Marble
    >trackball with a PS2 plug and then went onto a Microsoft Trackball
    >Optical with a USB plug and the supplied USB -> PS2 adapter with no
    >problems.
    >
    >The switch died and I managed to pick up a D-Link DKVM-2
    >http://www.expansys.com/product.asp?code=105699&partner=register
    >which looks like a far better quality box to me, very heavy and
    >separately powered but I seemed to have a problem that when I switch
    >from one computer to other the mouse is completely frozen, while first
    >is fine. If I press the sleep key, put the comp into sleep mode then
    >wake it up again the mouse wakes up so it's not a hardware problem.
    >
    >I switched off the computers, unplugged the KWM and started it all up
    >again and the same thing happened... but the computers were switched
    >round, the one the previous had functioned fine now had the mouse
    >freezing problem and the previously problematical one was now fine.
    >
    >I tried my old Logitech PS2 was fine although it was occasionally
    >locking up on both machines.
    >
    >I put in the Microsoft back in and thought I'll just have to live with
    >it.... and it now works fine - for how long I don't know.
    >
    >Are there any known problems with KVM switch's? I'm running XP on both
    >machines.
    >

    I can't be sure without reverse engineering a lot of KVM
    switches, but suspect that there are two distinctly
    different designs. One would simply "switch" (whether it be
    mechanically or electronically) between the two output
    lines, which the other would have a microcontroller
    emulating a PS/2 device, taking the mouse as input signals.

    The latter type should be more compatible, likely resolving
    your issue, but a special PS/2 device needing specifically
    identified by software (some cordless Logitech software
    perhaps?) might be better used with the former type...
    again, it's just a suspicion, I'd have to have a ton of
    spare/unused hardware to test, to confirm it.

    In other words, you're likley better served by the most
    modern KVM design you can find, the D-link looks a bit
    dated.
  2. Archived from groups: alt.comp.hardware.homebuilt (More info?)

    I'm afraid the D-Link KVM are not the best.
    Belkin aren't brilliant - but are at least relatively compatible.

    Do a google for KVM and carefully read through the many problems/solutions:
    o There may be a solution with the D-Link
    o Alternatively the USB-to-PS/2 adapter may be the problem
    o It is an extra layer of interfacing the D-Link may not tolerate

    D-Link are generally economic, ok - but can have compatibility issues.
    That goes historically with a lot of their kit right from the early days.

    There are cheap KVM switches on the market, eg, Shock, which despite
    the plasticy case, oddball connectors, and low price do work quite well.
    If using a laptop a separate PSU for the KVM tends to be required - as
    quite a few laptops do not provide enough power for the KVM to work.

    Do a google for the part number of the D-Link.
    --
    Dorothy Bradbury
    www.stores.ebay.co.uk/panaflofan for quiet Panaflo fans & other items
    www.dorothybradbury.co.uk (free delivery)
  3. Archived from groups: alt.comp.hardware.homebuilt (More info?)

    On Mon, 13 Sep 2004 23:38:29 GMT, "Dorothy Bradbury"
    <dorothy.bradbury@ntlworld.com> wrote:

    >I'm afraid the D-Link KVM are not the best.
    >Belkin aren't brilliant - but are at least relatively compatible.
    >
    >Do a google for KVM and carefully read through the many problems/solutions:
    >o There may be a solution with the D-Link
    >o Alternatively the USB-to-PS/2 adapter may be the problem
    >o It is an extra layer of interfacing the D-Link may not tolerate
    >
    >D-Link are generally economic, ok - but can have compatibility issues.
    >That goes historically with a lot of their kit right from the early days.
    >
    >There are cheap KVM switches on the market, eg, Shock, which despite
    >the plasticy case, oddball connectors, and low price do work quite well.
    >If using a laptop a separate PSU for the KVM tends to be required - as
    >quite a few laptops do not provide enough power for the KVM to work.
    >
    >Do a google for the part number of the D-Link.


    I picked up the D-Link very cheap second hand (from a boot sale!) so
    I'm not too bothered about it, I just thought there might be a setting
    in windows or a program to download that would automatically refresh
    the dead Mouse when I switched over.

    Fortunately the problem seems to be academic for the moment since
    after numerous switches and both computers being powered down it is
    working fine - I just wish I knew what I had done to make it work so I
    don't get this problem next time!


    -
    ButIstillneedtoknowwhat'sinthere!Thekeytoanysecurity
    systemishowit'sdesigned!Thatdependsonwhyitwasdesigned!
    Ihavetoknowwhatwhoeverdesigneditwastryingtoprotect!
    (Blakes 7, City on the Edge of the World - Vila in typical panic mode)

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  4. Archived from groups: alt.comp.hardware.homebuilt (More info?)

    On Wed, 15 Sep 2004 18:08:20 +0100, Luke Curtis <mfll78@dsl.pipex.com>
    wrote:

    >On Mon, 13 Sep 2004 23:38:29 GMT, "Dorothy Bradbury"
    ><dorothy.bradbury@ntlworld.com> wrote:
    >
    >>I'm afraid the D-Link KVM are not the best.
    >>Belkin aren't brilliant - but are at least relatively compatible.
    >>
    >>Do a google for KVM and carefully read through the many problems/solutions:
    >>o There may be a solution with the D-Link
    >>o Alternatively the USB-to-PS/2 adapter may be the problem
    >>o It is an extra layer of interfacing the D-Link may not tolerate
    >>
    >>D-Link are generally economic, ok - but can have compatibility issues.
    >>That goes historically with a lot of their kit right from the early days.
    >>
    >>There are cheap KVM switches on the market, eg, Shock, which despite
    >>the plasticy case, oddball connectors, and low price do work quite well.
    >>If using a laptop a separate PSU for the KVM tends to be required - as
    >>quite a few laptops do not provide enough power for the KVM to work.
    >>
    >>Do a google for the part number of the D-Link.
    >
    >
    >I picked up the D-Link very cheap second hand (from a boot sale!) so
    >I'm not too bothered about it, I just thought there might be a setting
    >in windows or a program to download that would automatically refresh
    >the dead Mouse when I switched over.
    >
    >Fortunately the problem seems to be academic for the moment since
    >after numerous switches and both computers being powered down it is
    >working fine - I just wish I knew what I had done to make it work so I
    >don't get this problem next time!
    >

    For anybody following the thread I *think* I gave found the solution:

    Although the manual says to boot computers at the same time this
    always produced the losing mouse problem, however if I make sure that
    I boot with the "other" machine on view (ie boot machine 1 with
    machine 2 selected, and then boot machine 2 with machine 1 selected)
    then the problem does not seem to show itself, I would imagine this is
    something to do with "training" the computer to take to off situation
    as normal.
    -
    ButIstillneedtoknowwhat'sinthere!Thekeytoanysecurity
    systemishowit'sdesigned!Thatdependsonwhyitwasdesigned!
    Ihavetoknowwhatwhoeverdesigneditwastryingtoprotect!
    (Blakes 7, City on the Edge of the World - Vila in typical panic mode)

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