VOGONS


First post, by SirNickity

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Iogear once made* a very nifty 8-port rack-mountable KVM switch with support for cascading (and selecting downstream ports through the keyboard), analog VGA, PS/2 keyboard and mouse, and -- this one's the killer feature -- automatic protocol conversion to serial for the mouse port .... with an optional PS/2-to-serial adapter.

(* By 'made', of course, I mean "contracted some OEM to manufacturer".)

The problem is, that serial adapter is not mentioned in the product catalog of the new-in-box KVM that I bought. It's not listed on their web site. I've not found any references by Googling. So, I thought, hey... maybe tech support can look it up and give me a part number to track down. Or, if the entity on the other end of the web form is a human being and not an 80's answering machine with a worn-out tape, maybe even a wiring diagram! (lol -- my own naivete can be so endearing sometimes)

Here goes:

I have just acquired two GCS138 KVMs. I need to control a couple of older PCs that have serial mouse interfaces. The manual says this is possible with the Miniview Ultra+ model, but it requires an adapter. The manual also specifically says that I can't use any adapter, it has to be an Iogear adapter.

However, I can't find any reference to this adapter on the Iogear site. Is there a part number I can look for? Failing that, is it a passive adapter that can be wired using a custom cable with mini DIN and DB9 serial cable ends?

After only a day, I got back:

The GCS138 is a discontinued legacy device and any adapters that may listed in the manual would no longer be available. * BEEEEerrreEEEEP*

Well, what did I expect. But hey, if it's worth doing, it's worth doing twice.

Yup. So. Page 10 of the manual says:

"You may need to attach a PS/2 to AT adapter on the keyboard cable if your computer has an AT keyboard connection. Also, if you do not have a PS/2 mouse port you will need to use our PS/2 to Serial adapter to connect the mouse cable. You can use any manufacturer's PS/2 to AT adapter, but you must use our PS/2 to Serial adapters for the mouse."

Did such an adapter actually ever exist, or was it just an April Fool's prank? If the former, are you at least able to tell me its part number? I understand you may no longer sell it, but if one was ever sold to anyone in the history of time spanning from the manual's copyright date of 2003 to now, it's probably up on eBay, and I would like to buy it. I just need to know what it is I'm searching for."

I don't anticipate a reply. If I get one, it'll probably just be an off-hook signal.

I did, however, receive three invitations to fill out a survey about my experience immediately upon submitting the initial ticket. What they lack in information they more than make up for in aggressiveness.

Reply 1 of 19, by Horun

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Good Luck ! Curious why it would need a special ps/2 mouse adapter when it works with standard serial mice and does not require a special ps/2 keyboard adapter. Have you tried a standard adapter with a mouse that is ps/2 and serial compatible like an original MS Intellimouse ? I understand getting all the original parts but think I would try it with other parts to see if it works.

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor.

Reply 2 of 19, by SirNickity

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Other way. It uses PS/2 mice and can allow you to control serial computers. I thought that might be particularly interesting 'round here.

So far, though, I've gotten a suggestion to use an AT keyboard adapter, and a comment saying "the serial adapter is not included". From tech support. sigh.

Reply 3 of 19, by xjas

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My ATEN MasterView Plus does the same thing... It only accepts PS/2 mice for input, but will happily convert this to serial internally if you use a bog-standard mouse converter on one of its outputs. I'd be kind of surprised if IOGear's version requires some proprietary adapter.

twitch.tv/oldskooljay - playing the obscure, forgotten & weird - most Tuesdays & Thursdays @ 6:30 PM PDT. Bonus streams elsewhen!

Reply 4 of 19, by SirNickity

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Yeah, I would bet my cat that it's the same box. AFAIK, ATEN is the OEM for (some / much / all?) of their stuff, and based on an image search, they could be twins. I was hoping to get one genuine adapter so I could verify the pinout before making some custom cables, since there wasn't ever a standard for how an adapter for those two interfaces is supposed to be wired. I suppose I could just dig through my box of junk and try a random adapter. Hopefully RS-232 voltages don't offend the PS/2 data pins if they're not meant to connect the way some random adapter does it. I have no faith that Iogear will have a definitive answer to give me though. If it worked for you, that gives me some hope.

Reply 6 of 19, by dionb

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xjas wrote on 2020-03-09, 20:59:

My ATEN MasterView Plus does the same thing... It only accepts PS/2 mice for input, but will happily convert this to serial internally if you use a bog-standard mouse converter on one of its outputs. I'd be kind of surprised if IOGear's version requires some proprietary adapter.

Oh... I have an Aten MasterView as well, I think I'm going to try something out tomorrow 😀

Reply 7 of 19, by SirNickity

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If you should feel inclined to continuity test the pins, that would be awesome, but don't go to too much trouble on my account. I'll just give it a try. They're fairly cheap, so the biggest loss will be having to re-cable everything if I blow something up.

Reply 8 of 19, by xjas

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No worries... I needed this info for myself anyway, since I didn't realize there wasn't a standard pinout for these things. Here's the adapter I use with mine:

20200309_162646.jpg
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I don't know if this is exactly the same as the one ATEN/IOGear would sell you, but it works for me. CuteMouse recognises it and even the scroll wheel works IIRC.

Note that (as stated in the image) I measured the front face of the female connectors on the adapter itself. The pinout on the mouse side (or on the rear of the connector, where you solder wires to) would be reversed L-R if you're making your own.

twitch.tv/oldskooljay - playing the obscure, forgotten & weird - most Tuesdays & Thursdays @ 6:30 PM PDT. Bonus streams elsewhen!

Reply 9 of 19, by Horun

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SirNickity wrote on 2020-03-09, 19:40:

Other way. It uses PS/2 mice and can allow you to control serial computers. I thought that might be particularly interesting 'round here.

So far, though, I've gotten a suggestion to use an AT keyboard adapter, and a comment saying "the serial adapter is not included". From tech support. sigh.

Ahh ok I thought it backwards 😁. Then a PS/2 mouse that is serial compatible and a adapter like xjas shows

xjas wrote on 2020-03-09, 23:37:

No worries... I needed this info for myself anyway, since I didn't realize there wasn't a standard pinout for these things. Here's the adapter I use with mine:

20200309_162646.jpg
I don't know if this is exactly the same as the one ATEN/IOGear would sell you, but it works for me. CuteMouse recognises it and even the scroll wheel works IIRC.

Think I will check the ps/2-serial adapter that came with one of my mice to see if it matches. Thanks.

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor.

Reply 10 of 19, by SirNickity

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xjas wrote on 2020-03-09, 23:37:

No worries... I needed this info for myself anyway, since I didn't realize there wasn't a standard pinout for these things. Here's the adapter I use with mine:

Fantastic. Thank you!

Horun wrote on 2020-03-10, 01:25:

Ahh ok I thought it backwards 😁. Then a PS/2 mouse that is serial compatible and a adapter like xjas shows

Uh, no. 😀

The KVM has a console port where you plug in the mouse, keyboard, and monitor. The KB/mouse ports are both PS/2, so you would plug in a PS/2 mouse.

The KVM's PC inputs (1-8) have PS/2 keyboard and mouse ports as well, HOWEVER, you can use a PS/2 to serial adapter to connect the KVM to the computer's serial port, and control the PC as if you were using a serial mouse.

The PS/2 to serial protocol conversion happens within the KVM. You use a PS/2 mouse (not serial compatible --or at least it doesn't have to be, as it's used in PS/2 mode) and the KVM converts that to serial protocol and, with a passive adapter, speaks serial to the PC.

***

Really glad I started this thread. As expected, Iogear gave up and said they didn't have any info on the official adapter.

I had already decided to take one of my KVMs apart and check to see if any of the n/c pins were being used for serial. In the absence of that, I probably would've tried an adapter to see what happened. Maybe I would be lucky enough to have one with the right pinout, but having proof that something works is always better. 😀

My next goal is to see about adding a parallel, buffered auxiliary VGA output so I can run one output to my OSSC and on to the HDMI jungle that follows, and the other to a CRT.

Reply 11 of 19, by xjas

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SirNickity wrote on 2020-03-10, 18:10:

Really glad I started this thread. As expected, Iogear gave up and said they didn't have any info on the official adapter.

I've had a batting average of virtually zero emailing companies for technical info like that, even on stuff they supposedly still "support." Unless you're one of their Valued Industry Partners(tm), product support is a sham. These companies know that 99.8% of the time they can get away with just brushing people off, so that's what they do. 😠

SirNickity wrote on 2020-03-10, 18:10:

My next goal is to see about adding a parallel, buffered auxiliary VGA output so I can run one output to my OSSC and on to the HDMI jungle that follows, and the other to a CRT.

What are you adding the second VGA output to? The KVM itself? If so, please post up some pics with what you figure out because I'd be interested in how you do it. I'm running a little 4-port powered VGA duplicator (from my DOS PC output, before the KVM) in order to split the signal off for my capture card, but it makes for a bunch of spaghetti under the desk.

twitch.tv/oldskooljay - playing the obscure, forgotten & weird - most Tuesdays & Thursdays @ 6:30 PM PDT. Bonus streams elsewhen!

Reply 12 of 19, by SirNickity

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Yeah, that's my idea. I haven't taken screwdriver to case yet, so I don't know how accessible the RGBHV lines actually are. I did look at one compact KVM and the board was positively crammed chock full, so there would've been no easy way to mod that one. But, I figure a rackmount unit probably has room to spare, so hopefully the board layout is generous enough to make tapping off of it fairly easy.

There's plenty of panel space to add a second VGA port, so I would just need to grab the video/sync signals before the output series resistors to avoid attenuation issues, maybe buffer them with an appropriate high-speed op-amp (depending on the drive capability of whatever the existing output buffer is), add its own series Rs and the physical port... voila. I would leave the EDID lines disconnected on the mirror port, since you can't exactly cater to different resolution/refresh requirements from the same input signal anyway.

My approach is to get everything to HDMI as close to the source as possible. My digital video distribution network is insane, but it's so much easier to deal with than analog RGB. My capture box (hopefully en route as we speak) uses an Intensity Pro 4K card, which has analog inputs (480i+ only, no 240p), but I only feed it HDMI from the scalers.

But... I still want the option to use CRT monitors for composite / S-video / component / RGBS / VGA.

Reply 13 of 19, by xjas

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I know it's less satisfying than DIYing it, but you might be able to grab one of these cheap 2-port powered VGA splitters and steal its PCB:

AV25243-40.jpg
It already has the amplifier circuit you want to build, and you can relocate the ports however. I bought one off Ebay for like $9 shipped. Did its job just fine until a friend gave me the 4-port splitter I'm currently using.

twitch.tv/oldskooljay - playing the obscure, forgotten & weird - most Tuesdays & Thursdays @ 6:30 PM PDT. Bonus streams elsewhen!

Reply 14 of 19, by SirNickity

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You know, I was all set to use a cheap and cheerful external box to get the job done, but the sheer number of DC power bricks in one room is seriously getting to be an issue. 😉 I can't buy power strips fast enough to keep up! The additional cabling and spot to shove the box is another problem. Just one more thing to fall on my head when I'm back there trying to plug in an Ethernet cable or whatever.

I know you mean to suggest that I could mount the guts internally to the KVM, but I don't think there's much to be gained by cannibalizing an existing box. The hardest part of this project is going to be modifying the back panel for the additional port. The existing output will stay untouched, save for the pre-series-resistor tap to the second output. Not sure I even need to amplify it, so long as whatever's there can supply two 75R terminated loads -- which it probably can. If so, a passive tap wouldn't even really need a PCB. Wires with inline resistors would probably work fine (although I'm obsessive about that sort of thing and would probably spin a small PCB anyway.) 😀

But who knows. It's still all speculation until I get in there and see what's what.

Reply 15 of 19, by dionb

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dionb wrote on 2020-03-09, 22:54:
xjas wrote on 2020-03-09, 20:59:

My ATEN MasterView Plus does the same thing... It only accepts PS/2 mice for input, but will happily convert this to serial internally if you use a bog-standard mouse converter on one of its outputs. I'd be kind of surprised if IOGear's version requires some proprietary adapter.

Oh... I have an Aten MasterView as well, I think I'm going to try something out tomorrow 😀

And... it didn't work with my CS-88A. Not had time to check the pinout of the only PS/2 to serial adapter I could find, so might be that and not the KVM itself.

Reply 16 of 19, by SirNickity

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Fingers crossed. 😀

This will likely be a weekend project for me. I have some CD-ROM drives to clean, re-lube, and retrobright before I can reclaim my workbench enough to take apart another device. After a while, I start losing track of which screws belong to which thing.

Reply 17 of 19, by hwh

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I hate that word "legacy." So full of themselves. It's like some Taiwanese didn't know how to say "old unsupported stuff we barely acknowledge" and found "legacy" in the dictionary. It's like calling a used car "pre-owned," but in a more egotistical way. "This is part of our tremendous legacy, which means go to hell."

Reply 18 of 19, by SirNickity

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Pretty much. Tech support is intended for helping people with complicated things like matching the green plug with the green port, and even advanced tasks like plugging the cable from the TV into the port next to the words "HDMI Out". You know, a remix of the "put the square piece in the square hole" game that most people start practicing before they're able to speak, and apparently you're meant never to graduate from. 😉

The days where you would get schematics with your purchase, so you're empowered to replace a component if it fails? Yeah... The technical types who step out of line and do shady things like opening the cover, well, those people are tantamount to criminals.

We expect a lot less capability of people these days, and the population has met those expectations.

I must be getting old, I'm starting to sound like somebody's grandpa. 🤣

Reply 19 of 19, by gdjacobs

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xjas wrote on 2020-03-10, 19:13:

I've had a batting average of virtually zero emailing companies for technical info like that, even on stuff they supposedly still "support." Unless you're one of their Valued Industry Partners(tm), product support is a sham. These companies know that 99.8% of the time they can get away with just brushing people off, so that's what they do. 😠

It never hurts to ask. I was astounded that Hercules was able to provide a pinout for a Fortissimo breakout cable.

All hail the Great Capacitor Brand Finder