Installation manual

Hardware & Software Compatibility
The RGB monitor has two implementations that should be of interest to the
Apple //e owner. The Apple type RGB differs from the IBM RGB in two
ways. The major difference is that Apple uses a composite synchronization
signal. This signal has bath the horizontal and vertical pulse information in
it. IBM type monitor uses two separate synchronization signals, one for the
horizontal sweep and another for the vertical sweep. Feeding the Apple type
synchronization to an IBM produces a picture that both rolls and tears left to
right. The second difference is not as critical, as it does not effect the stability
of the display, but it is noticeable. Since there are four color signals to work
with (red, green, blue and intensity) there are sixteen unique colors that can be
generated. Apple and IBM do not use the same combination of RGB signals to
define these sixteen colors, five of the color patterns do not match. For
example, Apple gray comes Out as brown on the IBM RGB monitor. If you
have an IBM type monitor, don’t panic.
Checkmate Technology has two different RGB cables, one with a DB-15
connector for TTL Apple RGB video, and one with a DB-9 connector for TTL
IBM RGB video. The DB-15 cable is intended to connect to Apple TTL RGB
monitors. The DB-9 cable turns the Apple RGB color and video signals into
the IBM TTL RGB format. Each of these cables comes with an instruction
manual and the necessary hardware for installation. Figure 2.2 on page 17
shows the connection for the RGB cable.
There is one more subcategory of RGB monitors. TTL and analog. The TTL
RGB monitor expects each color to be either on or off and the analog, actually
digital, expects each color to be one of sixteen voltages. The difference is that
the TTL can generate sixteen unique colors and the analog can generate 4096
unique colors. The Apple IIGS uses the analog RGB type monitor.
Now that the background has been covered we can talk about monitor options.
These options include:
- switch selectable between Apple TTL and IBM ‘TTL
- switch selectable between TTL and analog RGB
- switch selectable composite color and RGB
- switch selectable monochrome text display
- switchable from color television to RGB monitor
- may have a sound output
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