GD-1220/1221
© 2006 - 2008 TOSHIBA TEC CORPORATION All rights reserved
ELECTRICAL CIRCUITS
4 - 14
The monitoring signal selected by IC9 is input to the analog switch (IC10) to select the output sound
volume. The sound volume is selected by switching IC10 according to the SPVOL0-2 signals output
from the ASIC and selecting an input resistance for the monitoring signal.
The relation between the signals and sound volume is as follows.
The monitoring signal whose volume is controlled by IC10 is amplified by the OP amplifier (IC17), then
output to the speaker.
* Values in [ ] are GD-1221 in case that the descriptions vary between GD-1220 and GD-1221.
Sound volume
SPVOL2
SPVOL1
SPVOL0
Max. (7)
LOW
LOW
LOW
(6)
LOW
LOW
HIGH
(5)
LOW
HIGH
LOW
(4)
LOW
HIGH
HIGH
(3)
HIGH
LOW
LOW
(2)
HIGH
LOW
HIGH
Min. (1)
HIGH
HIGH
LOW
Silent (0)
HIGH
HIGH
HIGH
Signal Name
Type
Active
Description
Destination
TONESEL
O
H
Line/Tone Selection Signal
IC9
RING/TONE
O
H
Ring/Tone Selection Signal
IC9
SPVOL0-2
O
H
Speaker Volume Control Signals 0-2
IC10
08/08
Summary of Contents for GD-1221
Page 1: ...SERVICE MANUAL FACSIMILE GD 1220 1221 File No SME060017B0 R060121B2200 TTEC Ver02_2008 08 ...
Page 6: ...GD 1220 1221 2006 2008 TOSHIBA TEC CORPORATION All rights reserved CONTENTS 2 ...
Page 34: ...GD 1220 1221 2006 2008 TOSHIBA TEC CORPORATION All rights reserved LSU RELATED FUNCTIONS 2 16 ...
Page 78: ...GD 1220 1221 2006 2008 TOSHIBA TEC CORPORATION All rights reserved ELECTRICAL CIRCUITS 4 18 ...
Page 80: ...GD 1220 1221 2006 2008 TOSHIBA TEC CORPORATION All rights reserved INSTALLATION 5 2 ...
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