Apple II and RGB Video By Joel Buckley 11/7/2002 There have been a number of questions related to RGB video on the //e, //c, and Laser 128. I could only find limited info on these topics in the FAQs, so I thought I'd add what I have in my notes and references. I offer no guarantee that this is 100% accurate. In the Apple // series of computers, there have been 15 pin video ports on the Apple ///, Apple //e (option), Apple //c, Apple //c+, Laser 128, and Apple IIgs. Despite all using a 15 pin connector, most of these ports are different and incompatible! RGB may provide crisper, higher resolution displays than televisions or composite video displays. But RGB is not one standard. RGB monitors may use different frequencies, digital #s of colors (8 color, 16 color, or analog) and different sync encoding (separate vertical and horizontal sync, or composite sync, or sync mixed with the video signal). Early IBM computer used a type of RGB display which they called CGA. It is 16 color, RGBI (Red,Blue,Green,Intensity) and runs at 60Hz vertical 15KHz horizontal scan rate. These frequencies are the same as a regular TV set. The Apple II family uses these same frequencies. Later, higher resolution monitors, like EGA and VGA, use higher scan rates and generally are not compatible with the Apple II series. I think the Apple /// was one of the earliest versions of RGB for the Apple II family. Here's the pinout: Apple /// 1. Shield Ground 2. Green 3. Comp Sync 4. N/C 5. Red 6. Ground 7. -5v 8. +12v 9. Blue 10. Intensity 11. NTSC B+W 12. NTSC Color 13. Ground 14. -12v 15. +5v (I don't have an Apple /// and have not verified this myself.) The Apple //e had an RGB option which was very similar to the Apple ///. I actually have 2 of these boards (though I haven't hooked them up to an RGB monitor.) I believe it was called the AppleColor 64k 80 column card. The identical card was sold by a company called Video 7 (maybe they developed it?) They were not that much different from the early big 64k/80 column cards. They had a 16pin ribbon cable connector on top (which connected to a DB-15 connector). The matching monitor was called AppleColor 100, The pinout is basically a subset of the Apple ///. Apple //e 1. Shield Ground 2. Green 3. Comp Sync 4. N/C 5. Red 6. Ground 7. N/C 8. N/C 9. Blue 10. Intensity 11. N/C 12. N/C 13. Ground 14. N/C 15. +5v I believe some of the memory expansion cards for the //e made by Applied Engineering also had an RGB option. I don't have any information on them. The Apple //c and //c+ They also had a video expansion port which did not directly do RGB. The port could drive an LCD display (very rare). It also carries composite video and sound, so some adapter cables plug into it for those-but these are not RGB. There was an adapter made by Telemax called the Peacock model CM2C that converted these signals into RGB. I do not have one of these. Apple //c, //c+ 1. TEXT 2. F14M 3. COMP SYNC 4. SEGB 5. SOUND 6. LDPS 7. WNDW 8. +12v 9. PRAS 10. GR 11. CGSEROUT 12. NTSC (Composite video) 13. Ground 14. VIDD7 15. CREF Laser 128 This was an Apple //c clone. But its video port differs from the //c. While I believe it may work with the //c LCD display and with adapter cables that split out composite video and sound, it also has the signals needed for an RGB display without any extra circuitry. Laser 128 1. INTEN 2. F14M 3. RED 4. BLUE 5. SOUND 6. LDPS 7. DSPEN 8. +12v 9. HSYNC 10. /CSYNC 11. CGSEROUT 12. NTSC (Composite video) 13. Ground 14. VSYNC 15. GREEN Then there was the Apple IIgs. While it uses the same frequency monitor as the others, it uses analog video signals with superimposed sync signals. Besides its own monitor, it was compatible with a few other brands. Apple IIgs 1 Signal ground (Red) 2 Analog RED with sync 3 Composite sync 4 No connection 5 Analog GREEN with sync 6 Signal ground (Green) 7 -5 volts DC 8 +12 volts DC 9 Analog BLUE with sync 10 No connection 11 Sound 1V peak-to-peak 12 NTSC/composite color video out 13 Signal ground (Blue) 14 No connection 15 No connection In general Color monitors designed for the Macintosh have higher frequencies and aren't compatible with Apple II computers. There are exceptions to this. I believe there was a VGA board for the IIgs called Second Sight. Then there are devices called scan doublers, which may let Apple II video be displayed on some monitors which operate at twice the frequency as the Apple II. IBM CGA RGB Monitors I present this information because these monitors were once fairly common and you may want to try to hook them up to your Apple. Sometimes the Apple provides Composite Sync and the IBM wants separate Vertical and Horizontal. You can build a circuit to split them apart. But first try running the composite sync into both. Sometimes it will work. Trying to make one of these work with a IIgs is probably more trouble than its worth, especially with IIgs monitors from school surplus being a dime a dozen. Trying the reverse, getting a Iigs monitor to work with a //e or Laser 128 is also rather complicated. But wiring a CGA monitor to Apple ///, //e with RGB output, or Laser 128 may be doable with just a cable. Perhaps even more common than CGA monitors, were monochrome digital (MDA) or TTL or Hercules compatible monitors. These used a 9 pin connector very much like the CGA, with monochrome Video output on pin 7 (Red,Green,Blue unused). Intensity was used. These monitors worked at 50Hz vertical, 18KHz horizontal instead of 60/15Khz. Many PC clones could provide either of these video on the same connector. And I even have an odd hybrid, a CGA mono, which takes RGBI at 60/15K and displays it greyscale on a mono monitor. IBM CGA 1. Shield Ground 2. Ground 3. Red 4. Green 5. Blue 6. Intensity 7. Mono (not CGA) 8. Horizontal Sync 9. Vertical Sync Some additional comments: Improvement with the digital monitors may not be as much as you would expect. The Apple does some tricky things with color and video in its high res and double hi-res modes. These don't always translate well into digital. The AppleColor composite monitor gives a pretty good picture. It also has a black and white switch which can improve the display quality on text and monochrome graphics. The Laser 128 has a mono/color switch which can often improve the display for text and graphics when set to mono. I believe the Apple digital monitors are a little bit different than the IBM type. They use something called XRGB or linear-weighted summing. Standard RGB actually has bright and dim versions of 8 colors. The Apple produces 16 (or 15) different colors. Many are the same on both, but not all.