On Fri, Mar 23, 2012 at 02:14:21PM -0700 I heard the voice of Joe Ford, and lo! it spake thus: > > There must be monitors with DVI-A female (and only DVI-A) otherwise > why have such a connector. When I ordered a VGI to DVI cable what I > was sent was the VGA/DVI-A cable which is of no use to me.
That's the general use case for DVI-A connectors; going from the DVI controller end to a VGA on the device end. A general purpose video card will practically always have a DVI-I (both outputs) socket on the back. Into a DVI-I port, you can plugin a DVI-A plug (passing only analog), a DVI-D plug (passing only digital), or a DVI-I plug (passing both). Both electrically and physically, the DVI-I is a superset; both itself and the two more specialized variants can plugin to it. Hence, why the card will almost certainly be DVI-I. And since there's not much point using a DVI port if you're only going to output analog and no digital, you can pretty well assume any card is putting out at least the digital side. Certainly anything in the last 5 or 6 years, since LCD's are the lion's share of the market. My video card is something like 7-8 years old, and it has 2 digital-out DVI ports on it. If you're going to a LCD, you pretty well always want a digital in. Even when they take analog (as in a 15-pin VGA), they just turn that into digital internally, since that's how it controls the pixels. So, a LCD will generally have a DVI-D port. Maybe occasionally a DVI-I, just for the extra connector compatibility (you can put a DVI-D plug into a DVI-I port, but not vice versa), but the analog side will probably not be connected. On the other hand, a CRT needs that analog steering; that's how it moves the beam and turns it stronger and weaker. There may be some CRT's out there with a digital in (I haven't seen any, but It Stands To Reason(tm)), but if so, they're going to have to convert it into analog internally to be able to display the signal (sorta the opposite of putting analog into a LCD). So, a common config for this is a cable with a DVI-A on one side, and a DE-15 VGA connector on the other. Possibly, it may have a DVI-I connector on the device side instead, and only hook up the analog pins, but usually not, since that cuts down on the ports it can hook into (it could only hook up to a DVI-I, not a DVI-A). I doubt there are many device-side DVI-A ports. There're sure to be some, for weird special needs, but I'd definitely expect them to be niche cases. If something really wants analog, it would just use DE-15 since that's already all over the place on analog eq. There may be some use of device-side DVI-I, for devices that could take either digital or analog. But then, it's common enough to just have both a DVI and a VGA like on your monitor, so that's probably uncommon too. > My PC which is several years old has only the 15 pin VGA output. If > my monitor had a DVI-I input, which it doesn't, it should work with > this cable, because it will work digital or analog. If it did, yah. I'd expect such monitors to be rare though; having a VGA port to handle an analog in is still so standard, there's probably not much point in adding the complexity of trying to take analog over the DVI too. > I was just guessing that because they were cheap they were analog > but I had no way of knowing for sure. I'd bet they're all just digital. It's _more_ work to turn it into analog, after all. For a ref, look at the Radeon 5000 series at Newegg: http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007709%20600030349%20600007320&IsNodeId=1&name=Radeon%20HD%205000%20series The 7000 series are mostly out now, so the 5000 is almost 2 gens back. The 4000's are old enough they're actually often more expensive. There's a good selection of 5450's under $30 shipping and all, and they all have at one analog (VGA) and 2 digital (DVI and HDMI) outs. You could poke around for a 4/5000 on ebay maybe, but I'm not sure you'd actually save much in the end at those prices, and you wouldn't get as good a return policy. > My PC has the 15 pin output and the P3SVGA has that connector also. > If I'm going to have only one monitor it will have to have 2 of the > 15 pin inputs or one 15 pin and one DVI-A. You could try getting a KVM switch and just switch the one 15 pin between the two. But a cheap KVM will fuzzy the picture all up, and an expensive one would be expensive. It'd be way cheaper and you'd be way happier spending 30 bucks on a video card. > Or I'll need to go to 2 monitors. Well, any excuse... 8-} -- Matthew Fuller, N3TZJ <n3...@n3tzj.org> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
