5. Central Highway & Fast I/O Modules
GEM80-400
Page 5-10
ALSPA GEM
80-400 SERIES CONTROLLERS TECHNICAL MANUAL
Issue 3 04/99
or colour printers. When 'daisy-chaining' monitors, make sure that the 75
Ω
/high
impedance input switches on each monitor are correctly set. Set the last
monitor switches to 75
Ω
and all previous monitors in the chain to high
impedance. Also illustrated, on the front panel, is the Video Program Port to
which a suitable GEM
80 programming tool, such as Gemesys 3, may be
connected.
Further details are available in the relevant IMAGEM Technical Publications.
Also included in T493 are details of recommended coaxial-axial cables and
connectors.
If a monochrome monitor is to be connected, the IMAGEM program must be
written to display various shades of the chosen colour (either RED, GREEN or
BLUE). The monitor is then connected to the relevant connector on the
termination panel and to the composite sync. output. Figure 5.3 illustrates the
IMAGEM connections to be made on the upper backplane of the Enhanced
Controller subrack.
Figure 5.3 - IMAGEM Connections on the Enhanced Controller Subrack Upper
Backplane
5.8.
IMAGEM CRT Monitor Frequency Selection
The 8284-400x IMAGEM Processor Module has been improved and now
produces the higher frequency video signals that are used by readily available,
high quality, video monitors. However the 8284 may be configured to use the
same monitors as the 8219 IMAGEM Module by placing a jumper or wire-link
between the pair of wire wrap posts associated with the slot or slots containing
the 8284-400xs. These wire wrap posts are accessible once the power supply
module has been removed. See figure 5.3 above. To configure the slot to be
compatible with the older style monitors connect a wire link between IM1 and
0V if the 8284 module is in slot 1. IM2-IM5 correspond to slots 2 to 5
5.9.
IMAGEM Compatibility
GEM
80-400 Enhanced Controllers accommodate the IMAGEM graphic video
only and NOT character-based video systems.
