IBM RT Series Hardware Reference Manual page 20

Horizontal Drive
Free-running horizontal oscillator
Normally low, positive going TTL pulse
Nominal horizontal frequency of 24.68 Khz
Retrace blanking time of 8.0 usec.
Vertical Drive
Free-running vertical oscillator
Normally low, positive going TTL pulse
Nominal vertical frequency of 92 Hz
Nominal frame rate of 46 Hz.
Operator Control
Size
Brightness control adjusts brightness of displayed image. (Clockwise rotation of control
increases brightness)
Raster switch (diagnostic aid) produces visible raster independent of video input. (Raster
switch function occurs at full clockwise rotation of brightness control)
Width 327 mm (12.9 in.)
Depth 331 mm (13.0 in.)
Height 266 mm (10.5 in.) without pedestal
305 mm (12.0 in.) with pedestal
2 Advanced Monochrome Graphics Display