> is a VGA cable the 'regular' cable 'we' are used to for monitors? Yes > > what is a DVI cable & to what does it attach?
It's the digital version of the analog VGA cable. For more info than you would ever want to know: http://www.thesmallest.com/lessonettes/dviandvga.html Richard P. thesmallest.com lessonettes: short essays on whatever Computers connect to monitors using one of two methods; the traditional VGA (Video Graphics Array) format or the newer DVI (Digital Video Interface). The facts VGA, which stands for Video Graphics Array, has been the standard method for connecting monitors to Macs since the late 1990s and to PCs for some years before then. The newer DVI format, which stands for Digital Video Interface, is the preferred connection method for most non-budget LCD displays, a number of higher-end CRTs, and even a small number of expensive video displays. VGA is being phased out in favour of DVI, although we’re still in the transition period where support for both is common. Some monitors contain sockets for each format, and the Mac mini comes with a DVI to VGA adaptor dongle to help users with older displays connect to its built-in DVI port. Much of the DVI specifications and its differences from VGA aren’t widely understood. VGA is based on analog signals, at least in terms of what goes across the cables themselves. Although the monitor signal always starts and its life as digital. With VGA systems it is converted to analog as it leaves the graphics card for the purposes of sending it through the cable, then converted back to digital format at the other end, over in the monitor. One drawback of this is the inability to address the monitor’s picture elements - the individual pixels - precisely. This isn’t a problem with CRT displays, as they simply draw out the image as it arrives by passing an electron beam across the inside phosphor-coated surface of the glass screen. It becomes an issue when working with LCD displays, as their pixels are fixed, individual entities which need to have the incoming image pixels matched up to produce a clean result. The problem this causes with VGA connections is the need to apply phase and clock corrections to synchronise the signal with the display’s physical pixel array and its properties. When this is out of adjustment it can produce banding and other effects for reasons not dissimilar to what causes moiré patterning in printed work; the two different patterned arrays (the virtual pixel grid of the display signal and the physical pixel grid of the LCD itself) don’t match up, leading to regular bands of blurred detail and similar problems. Unlike the potentially imprecise way VGA works with LCD displays, the DVI signal is mapped to the physical frequency of the monitor’s pixels. The display signal can also degrade with improperly sheilded VGA cables, leading to poorer-quality results at the display end. This isn’t a problem in the same way with DVI, although there is still a maximum recommended length (5 metres) beyond which the signals may not be transmitted properly. In short, DVI provides a cleaner, faster, more precise display with hardware that supports it properly. This is all very well, but there is a small matter of different DVI formats to content with. Fortunately, these are designed to complement each other rather than actually being competing standards; the differences are essentially to do with handling displays with digital or non-digital inputs. There are three main kinds of DVI connections which are available; DVI-D, DVI-A, and DVI-I. DVI-D is the ‘true’ digital format. It is the normal format used for connecting digital LCD monitors to DVI graphics cards. DVI-A is the analog version of DVI; it is used to carry a signal from a DVI graphics card to an analog display, for example a CRT monitor. There is a digital to analog conversion applied here, but this still gives higher-quality results than a standard VGA cable. Finally, there’s DVI-I, the integrated format which caters for both digital and analog equipment. This doesn’t convert a pure DVI-D output to something a DVI-A device can use. But it will act as a DVI-D cable or a DVI-A cable according to your needs. The real benefit is that you don’t have to use two different cables if you use both digital and analog displays. Having said that, you’re pretty unlikely to run into trouble if you stick with the cables that come with whatever new display you buy. Where you need to take care is when buying cables separately. Although you’re unlikely to need anything other than a DVI-D cable when dealing with LCD screens, it could still be wise to consider buying a DVI-I cable to cover both eventualities. However, do be aware that some manufacturers have been making the blade part of the pin set in DVI-I cables larger than normal; this could affect how it fits in some equipment. There is, unfortunately, still more to the DVI connection format. DVI-D and DVI-I can come in single-link and dual-link forms. Fortunately, again, this isn’t as complex as it sounds at first. The dual link varieties provide twice as much power and deliver the data more rapidly than the single link kind. This has a practical benefit with larger monitors, in that it allows a higher maximum resolution to be transmitted. In compatibility terms, the physical difference between single link and dual link is purely a matter of the absence or presence of extra pins in the middle section of the plug; any DVI-D or DVI-I-ready graphics card can accept either level. Telling them apart Recognising the different DVI formats isn’t hard once you know what to look for. All forms of DVI have a flat blade at one side of the plug, slightly separate from the main group or groups of smaller pins. With the pure digital DVI-D format this is on its own, whereas the formats which support analog data (DVI-A and DVI-I) have four pins grouped around this flat blade. DVI-D and DVI-I connectors have two equal groups of small pins (if they’re single link) or one solid group (if they’re dual link), while DVI-A has fewer pins, unevenly distributed between the two groups. Computers or video? In the realm of home theatre setups the DVI connection format is becoming popular for making pure digital links between AV equipment. Some feel that the use of this format by the hardware manufactureres is being encouraged by the movie and video industry in place of FireWire because of data copying concerns with that arguably more flexible connection format. DVI can incorporate the HDCP (High-bandwidth Digital Content Protection) copy protection scheme developed by Intel for use with home cinema-level products. HDCP, however, is not relevant to those using DVI for computer monitor interfaces, where DVI is the best choice for modern monitor equipment. Banner > > > ************************************************************************* > ** List info, subscription management, list rules, archives, privacy ** > ** policy, calmness, a member map, and more at http://www.cguys.org/ ** > ************************************************************************* > ************************************************************************* ** List info, subscription management, list rules, archives, privacy ** ** policy, calmness, a member map, and more at http://www.cguys.org/ ** *************************************************************************
