Mac Compatible Projector (Super MultiSync??)

[Themk]

Well, this is surely somewhat of an oddity, as far as topics in this Conquests forum goes, but, I thought it would be appropriate to put it here.

So, I bought a projector recently. It is a Proxima Ultralight LS2. Now, you might be thinking, "Cool! It's a projector. But, how exactly does this relate to Macintosh?", well, for one it came with a Mac DA-15 to VGA adaptor, the one with six dip switches. But, the second reason(s) are why it is so appealing.

This projector does MultiSync like I have never seen before. It supports every obscure Mac resolution I've thrown at it so far, even identifying it as "Mac 13", or "Mac 16", etc. in the OSD. It syncs perfectly to those. But, it also does something else which I found very awesome- It supports IIgs video output.

Now, this is where we go into the "What were you thinking MK, were you trying to let the magic smoke out??" part. I already have the Mac video pinout pretty much memorized from working on my ADB KVM, and I checked out the pinout of the IIgs video port. Both are DA-15 connectors, and both have their R,G and B signal lines on the same pins. But this is where the stupid part beings, I decide to hook up my Mac VGA adaptor which I have used for quite a few things, and also hook up a VGA cable using that between my IIgs and this projector. And, it worked. Additionally, the OSD of the projector identifies the HSYNC and VSYNC rates correctly, as well as calling it "Analog RGB". Very cool, I honestly didn't expect this to work.

As always, pictures!: (Oh, and be sure to read the titles/descriptions I have given to each of the pictures)


Another interesting things is Gorgonops was talking about syncing and projectors, as well as a specific monitor in this thread: https://68kmla.org/forums/index.php?/topic/30554-mac-plus-external-video-mod-ttl-to-vga/?p=331885

 

[Gorgonops]

It's actually not *terribly* surprising a projector accepts IIgs output, as it's at NTSC resolution/scan rates and most full-featured projectors support those with composite/svideo/etc inputs. (Additionally, the projector may well also support SCART with an appropriate cable, and Apple IIgs output is essentially the same as SCART RGB.) That is nonetheless sort of cool; it implies the projector would also work with an Amiga, Atari ST, or other similar sort of machine.

Per the possibility that it could be made to sync with the output of an ad-hoc compact mac motherboard adapter, well, here's something you could *try*, perhaps. If you can convince your Mac and monitor adapter to output the 512x384 video mode targeted at the 12" RGB it would be interesting to see if the projector is flexible enough to sync with *that*. That runs at a 24khz Hsync, which makes it the only "standard" Mac external display resolution that's a lower frequency than VGA.

One thing you might find when messing with older LCD monitors (and presumably projectors) is they do tend to be more willing to accept "odd" video modes verses just puking with "out of range" if you dare ask them to display something other than a standard set of VESA resolutions@60hz. I have an old beige AOC 17" VGA LCD from 2002-ish that works (granted it doesn't look that great) with things like the 1152x870 mode output by old Sparc boxes using a VGA->13w3 adapter. Most newer LCDs will just tell you to get bent. The one sad thing, though, is that the *floor* on those old monitors still tends to be 31.5kz 640x480 VGA; there are a *few* that will go all the way down to NTSC frequencies (and possibly things in between), but they're rare.

(Or, in the case of a monitor that also has composite/svideo/component jacks, they'll support NTSC/PAL as a special exception, but still have a floor of 31.5khz on the VGA port.)

 

[Themk]

I would love to get 12-inch 512x384 output. Unfortunantly, I do not know what the correct DIP switches for that are.

My adaptor:

 

[Gorgonops]

Here's a manual page that covers the totality of what that adapter supposedly supports, but unfortunately it doesn't include the 512x384 mode; my guess is that the monitor it came with didn't like that mode so even if the adapter supports it it's via some undocumented setting. Here's a reference of what the sense pins on the monitor port need to be set to for various resolutions, I suppose you could either try poking at your adapter with a multimeter and seeing if you can discover if it's possible to set it up correctly, or cook your own cable.

 

[Themk]

Thanks for the information. I'll probably stick it with a multi meter, to see what happens, and then if that doesn't work, I feel confident building my own SENSE line magic.

 

[Cory5412]

Nice find!

I don't think any of those adapters will let you force 512x384 onto a PC monitor. They generally do 640x480 and up.

Regarding Mac compatible projectors, if this is going to be a point of possible collection, it may be worth looking at nView and perhaps at '90s inFocus stuff.

The InFocus projectors I'm thinking of in particular (LP series minus 580, basically) are all Multiscan Mac era from the mid-late '90s and have hilarious colored plastic accents. They use these proprietary adapter cables to take VGA and sound or Mac MultiSync video and sound and connect it to a single port on the projector. It's an interesting series to look at because you can basically look at them and tell pretty easily what the different projectors were for. One was pretty obviously a "multimedia" projector aimed at showing video and playing audio, one was meant as a traveling businessman projector, another was meant for tabletop use in conference rooms and on carts, and another was meant for ceiling hanging installations.

nView stuff is interesting because some of the early things (I'm thinking about the nSight in particular) are pretty clearly from the Mac II era and the nSight specifically included a Mac video cable, which is wired up to force a 640x480 mode. The nSight is also pretty neat as what I believe to be one of the first integrated computer projectors. It was essentially a slide projector but with an LCD display mounted permanently inside. It even used cheap inexpensive slide bulbs and slide projector lenses which you could focus yourself. The trade-off is that it's very dim.

The other thing to look at, from nView, Proxima, and inFocus really, are overhead projector LCD panels that were common in educational settings.

Anyway, one thing of note is that it looks like the Proxima LS2 is from 2000. That Mac video adapter probably didn't come with it. In general, once Apple shipped the blue-and-white G3 with a VGA port in 1999, all monitor and projector vendors dropped Mac adapters from their products immediately. The DIP switch adapters were gone even earlier - probably by 1996 or so Mac  displays were presumed to be for MultiSync compatible machines and so they generally included straight-through adapters.

My guess is that whoever used it hooked it up to their existing adapter and when they got rid of the projector, they got rid of their 10+ year old pre-Quadra Mac as well.

Regardless, it's neat and fun that it happened to work that way. I wonder if Proxima originally bundled a VGA to component video adapter or something like that. Adapting the IIgs display connector straight through like that would work well with very few regular computer displays.

 

[Themk]

Thanks for the post Cory, It's nice to know someone else other than me and G have interest in this.

The Mac VGA adaptor that is pictured above is just one of the ones I have laying around. That didn't come with the projector. Now, I don't have the adaptor that did come with the projector, but, the manual clearly states that yes it did come with an adaptor, and yes it has DIP switches (reference pages 5 and 13).

Another interesting thing as I was reading through the manual is the control port. It is an ADB port, as well as a PS/2 port, as well as a serial port using the supplied (don't have) adaptor. I want to find the software for Macintosh, to see if I can control it from ADB, which I think is really cool! (reference pages 12/13)

Checking out the manual lists analog RGB as a supported thing under the VGA support table, so, that's good to know its a 'supported' config. Overall, I really like this projector. I didn't even buy it originally as a mac conquest but it does make a good data projector, it was for playing DVDs from my DVD player.. For $5 at my local thrift shop, with a good bulb I felt like was fine deal. One thing interesting to note, is that even though I didn't get the goodies I wanted from the accessories list in the manual, it did come with a very long VGA cable.

Regarding trying to force 12-inch RGB resolution, I think I will cook up my own SENSE line magic, which should force that resolution.

 

[Cory5412]

Interesting about the manual mentioning an adapter. I hadn't seen anything else that new with one, but the adapters were cheap, and it was probably easier than doing what some of the desktop monitor manufacturers tried to do and have pc/mac versions.

Does the projector say it supports it? As far as I know, almost nothing outside of actual Apple monitors supports that resolution, and most of the Apple monitors do it by displaying a 512x384 pixel area at the center of the screen, using approximately the dpi of their "native" res (so basically, on an Audiovision or MCD, a 512x384 area in the middle of a 640x480 field or a 832x624 field.)

There's nothing that really benefits from it other than perhaps some machines can display more colors at that res. I would evaluate how important that is to your particular context, and then settle on upgrading the VRAM of the affected machine so it can display those colors at 640x480.

My interest in projectors was a high school era thing. I don't have/use one today, but I definitely had An Interest™ in using a projector for desktop computing back in the day. Every once in a while I entertain the notion of getting one, but bulbs don't last an awfully long time and I don't have any particularly good spaces or reasons for it today.

The other thing that probably caused some interest (especially in OHP models, although what I ended up with was an integrated model) was because Silicon Graphics had the "Presenter" display for some machines. I never had one of those, but I thought the idea was very interesting.