Re: KVM Switches
Ken Fairfield wrote:
> vmsmangler@xxxxxxxxxxxxx wrote:
> > William Webb wrote:
> >>On 5 Jan 2006 13:26:22 -0800, vmsmangler@xxxxxxxxxxxxx
> >><vmsmangler@xxxxxxxxxxxxx> wrote:
> >>>Galen wrote:
> >>>>We have one kind of Belkin 2-port KVM switches here and another newer
> >>>>switch from IOgear--model GCS612A.
> >>>>With my particular LK461, both of them have the same minor problem if
> >>>>certain special keys are pressed repeatedly. The symptom is that it
> >>>>sort of freezes up until another special key is pressed. One of the
> >>>>keys with this problem happens to be PF3, which is a pain since it's
> >>>>used for searching in EDT-style editors.
> >>>>I don't have another LK461 immediately available to determine whether
> >>>>the problem is in the keyboard itself, or in the switches. I'll have
> >>>>to borrow one from another system when nobody's looking. :-)
> >>>Thanks for the information. I checked iogear's website and also called
> >>>their technical people.
> >>>They claim to only support the 102 key keyboard so I am surprised that
> >>>is supports a true DEC
> >>>keyboard, e.g. LK461. From what I have determined from all responses is
> >>>that PC's keyboards
> >>>are scanset 2 while DEC keyboards are scanset 3. My 2 DPW 433/500au
> >>>workstations all have
> >>>keyboard detection problems during power-up testing by SRM. They also
> >>>have the error that
> >>>scan code 0xfa is not supported.
> >>>Retired VMS Systems Manager
> >>I seem to recall that there is much anecdocal data on which KVMs work
> >>with LK-style keyboards in the comp.os.vms historical record.
> >>NOTE: This email address is only used for noncommerical VMS-related
> >>All unsolicited commercial email will be deemed to be a request for
> >>services pursuant to the terms and conditions located at
> > I have checked the historical records for KVM switches, LK46x
> > keyboards, etc. Wow! Lots of information and somewhat conflicting but
> > very usefull.
> > I am curious if Ken Fairfield ever got the Belkin switch to work with a
> > true Alpha running VMS and using a LK46 type keyboard.
> Well, yes, with conditions...
> First as a reminder, I use an LK462 (black version of an LK461),
> an older-DEC-style Logitech 3-button mouse, and a "modern" LCD
> Samsung display, between a DPW600au and an IBM T41 laptop-via-port
> replicator (to get to the external keyboard/mouse/video).
> I had some initial problems with the DPW600au when hooked up
> through the Belkin. I finally determined that the mouse and
> keyboard connections were "flaky"; the plugs from the Belkin
> cables didn't seat firmly in the receptacles on the DPW.
> I solved that by trimming about 1mm of the insulation from
> the ground/barrel of the mouse and keyboard plugs. That
> solved the problem.
> I also seem to get what would appear to be discharge flickers
> on the monitor after the DPW has been on a while. It has a
> "standard" Elsa Gloria video card, so you'd think there wouldn't
> be any connector compatibility issues. I have it on my list to
> go back and see if I can do something similar to what I did
> with the keyboard & mouse connections to correct it, but it hasn't
> been enough of a bother to deal with yet.
> I have absolutely no problem using the laptop. I also have no
> problem on the DPW console, after power-up or shutdown (someone
> had mentioned a problem along those lines...).
> With both the laptop and the DPW, ALL the LK keys function as
> expected/desired (with either Exceed or KEA and suitable mapping
> tables on the laptop).
> Here's the big "your mileage may vary": I rarely have both computers
> on at the same time, so I rarely exercise the actual switching
> between computer function (Alt-F19, or Shift-F19, on an LK). I have
> done test and verified it works. I have verified that, contrary to
> the documentation, the switch WON'T go into continuous scan mode,
> something John Malmberg mentioned. [I have managed to get into
> situations where the active computer (the one displaying) wouldn't
> respond to the keyboard, but I think I was specifically banging on
> the F19 thingy in a way that confused the switch, or confused the
> computer...] But I believe for routine use, the switch functions
> quite adequately.
> Some commentary:
> I greatly prefer this "simple" Belkin over the Rose Mini-Vista I
> previously used. The difference is that the Belkin, when it switches
> (every time it switches), resends the keyboard initialization sequence.
> That means (a) there is a slight delay before you can type anything to
> the just-switched-to computer, but (b) the keyboard is put in the
> correct scan mode for that computer. In addition, the Belkin appears
> to just pass through any and all key sequences, not just a (semi-)
> limited set it knows about.
> The Rose, on the other hand, insists on (a) maintaining the keyboard
> in scan mode 2, and (b) translating key sequences to the scan mode
> the computer wants, scan mode 3 for the DPW. But for the DPW, that's
> a Catch-22 since at power-up, the console doesn't send the keyboard
> reset sequence (that VMS eventually does), so the Rose tries to talk
> to it in scan mode 2 instead. Ugh. You can program the port on the
> Rose to talk scan mode 3 (and there's a different special setting
> required for the mouse, IIRC), but when the Rose loses power, because
> both computers are off, it loses its programming! The work-around was
> to put a Rose-supplied external power supply between the switch and
> one of the two input keyboard lines. Finally, there were a number of
> LK key sequences that the Rose simply didn't know about and so wouldn't
> do the translation on. For the all the time I used the Rose, I needed
> TWO KEYBOARDS: one connected through the KVM that I'd use with the
> laptop, and the second directly plugged into the DPW. Sigh...
> I'm told by Rose that some of their more expensive models (but older)
> work correctly with LK keyboards in scan mode 3. I'm also told that
> some Raritan models, possibly with additional required "options", also
> work with LK keyboards and scan mode 3. In both cases, the complete
> solution is MUCH MORE EXPENSIVE and not necessarily more functional.
> In summary, the "cheap" commodity KVMs, while not officially supporting
> an LK keyboard, seem to work pretty well, at least the Belkin does.
> A bonus with the particular Belkin John recommended, the F1DL102P, is
> that it really saves real estate by having the two computer cable sets
> built-in/preconnected internally to the box.
> I don't speak for Intel, Intel doesn't speak for me...
> Ken Fairfield
> D1C Automation VMS System Support
> who: kenneth dot h dot fairfield
> where: intel dot com
Thank you Ken for your great reply. You have done very extensive
testing with the Belkin switch which confirms my thoughts about which
switch to purchase. Based upon your results I have decided to obtain
the Belkin F1DJ102P. This switch does not support audio but it does
have a button to switch systems. Hot Key switching is also supported
but I really like the idea of a separate button.
I will post the results of my testing this switch as soon as I can.
Thanks to all who have responded to this thread.
Retired VMS Systems Manager
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