Acer NA23WABAS Service Manual page 4

C o nne c to r P in D e s c riptio n
D -S U B Pin D e s criptio n
Pin N a me
1 Red - V id eo Red vid eo signal inp ut.
2 G reen- V id eo G reen vid eo signal input.
3 Blue- V id eo Blue vid eo signal inp ut.
4 G N D G ro und
5 D D C - G N D D D C gro und fo r the V ES A D D C 2 Bi functio n.
6 Red - G N D A nalo g signal gro und fo r the Red vid eo .
7 G reen- G N D A nalo g signal gro und fo r the G reen vid eo.
8 Blue- G N D A nalo g signal gro und fo r the Blue vid eo .
9 + 5 V + 5V inp ut fro m ho st system fo r the V ES A D D C 2 Bi functio n.
1 0 S ync- G N D S ignal gro und
1 1 G N D G ro und
1 2 D D C _ S D A S D A signal inp ut fo r the V ES A D D C B2 i functio n.
1 3 H - S Y N C H orizo ntal signal inp ut fro m the ho st system.
1 4 V - S Y N C V ertical signal inp ut fro m the host system.
1 5 D D C - S C L S C L signal inp ut fo r the V ES A D D C 2 Bi functio n.
1.3.1.3 Audio Jack (option)
This jack shall connect the audio input from
host computer.
1.3.2 Video Input Signals
Video Input Signal
1.3.2.1 Video Signal Amplitudes
The three video inputs consist of Red , Green ,
and Blue signals, each with its own coaxial cable
terminated at the monitor. These video signals are
analog levels, where 0 V corresponds to black ,
and 700 mV is the maximum signal amplitude for
the respective color, when each signal is
terminated by a nominal 75.0 ohms .For a given
monitor luminance levels are measured using this
defined video amplitude driving a monitor meeting
the termination requirements . The signal
amplitude is not to be readjusted to compensate
for variations in termination impendence.
1. Product Specification (continued)
D e s criptio n
1.3.2.2 Video Signal Termination Impedance
This analog video signal termination shall be 75
1% which shall be resistive with a negligible reactive
component.
1.3.2.3 Synchronization ( Sync ) Signals
The Horizontal Sync (HS) TTL signal is used to initiate
the display of a horizontal line. HS may be either active
high or active low, depending upon the timing .The
Vertical Sync (VS) TTL signal is used to initiate the
display of a new frame .VS may be either active high or
active low, depending on the timing .
1.3.2.4 Sync Signal Levels
The monitor must accept sync signals from both 3.3 and
5 volt TTL logic families.The inputs shall sense a logic 0
when the input is 0.8 volt or less and shall sense a logic
1 when the input is 2.0 volts or greater. In addition to
these level requirements , there shall also be a
minimum of 0.3 volt hysteresis provided for noise
immunity (typically by using a Schmitt Trigger input ).
That is , the input level at which the monitor actually
detects a logic 0 shall be at least 0.3 volt lower than the
level at which it actually detects a logic 1.If the monitor
sync processing circuits are designed around the 3.3
volt logic family ,then the sync inputs must be 5 volt
tolerant .
1.3.2.5 Sync Signal Loading
TTL input loading shall be equivalent to one TTL input
load. When logic 0 is asserted by a sync input , the
maximum current source from any single monitor sync
input to the driver is 1.6 mA .When logic 1 is asserted ,
the maximum current source from the driver to any
single monitor sync input is 400 uA .
1.3.2.6 Abnormal Signal Immunity
The monitor shall not be damaged by improper sync
timing , pulse duration , or absence of sync , or
abnormal input signal amplitude ( video and/ or sync too
large or too small) , or any other anomalous behavior of
a graphics card video generator when changing modes
, or when any combination of input signals is removed
or replaced . Additionally , under these conditions , the
monitor shall not cause damage to the driving source .
3
ACER V233H
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