Audio Board; Figure 2-7: Graphics Daughter Board - PictureTel Concorde 4500 Servicing Manual

UNDERSTANDING THE ELECTRONICS MODULE
AVIA<11:01>
GAVAIA<15:0>
PG 3
AVIA<16:01>
GRAFIXCS GRXDONE_L
J721
Interconnect to video board
PG 9

Audio Board

2-14
The following illustration shows a block diagram of the Graphics
board.
Graphics
calibration
constant
EEPROM
PG 3
GAVAIA<15:0>
PG 3 PG 7 PG 7
DATA_L<15:00>
DMAO<15:00>
J878
PG 9

Figure 2-7: Graphics Daughter Board

The Audio board (AI) is located in slot 8 on the Backplane. This
board provides an interface to the electronics module for external
audio equipment such as a VCR, the monitorÕs audio ampliÞer, and
the wired keypad.
The AI board supports an optional telephone interface daughter
board that provides an interface for a telephone line and extension
telephone. This telephone line can be used for audio-only
conferencing or to add telephone users as audio-only participants in
a videoconference.
Graphics
overlay
PG 6
GAGSD<15:00>
GOFSD0<15:00>
GRAFIXCS
GRXDONE_L
GOFSD0<15:00>
GAVAIA<15:0>
LUMOUT
GAVOGA
AVIA<19:17>
LDACLK_L
VGIA20_L
CHROUT
CSYNC
CDACLK
LDACLKX2
LHREF_L
20 MHZ
PLL
SCHREF_L
PG 2
PP 4,5,8
DMAO<15:00> CDACLK
Interconnect to video board
Output
framestore
0
PG 4
Output
framestore
1
PG 4
Luma 5 MHZ
D/A lowpass
converter (SINX/X)
PG 2 PG 2
Chroma Chroma
D/A bandpass
CDACLK
converter filter
PG 2 PG 2
2
SN
CSYNC
filter
PG 2
PG 2