Canon FAX-L1000 - Manual (Page 515)

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FAX-L1000 Chapter 5: Appendix
3.6.4 G4 board components
Fig. 5-73 Component bloock diagram
a) DTMF signal detection circuit
This circuit uses a dedicated IC (IC38 DTMF receiver) to detect a DTMF signal.
b) ISDN interfade IC (IC24)
This YAMAHA-made IC YM7405C has Layer 1 functions, Layer 2 functions(LAPD), and
Layer 3 interface functions for connection to an ISDN circuit.
c) PCM CODEC IC (IC51, IC69)
The PCM CODEC IC, OKI-made MSK7578VMS-K, converts analog audio signals output
from a G3 modem to PCM digital signals to implement G3 transmission through ISDN
lines. This IC converts PCM digital signals to analog audio signals.
d) Modem IC (IC52, IC67)
The modem IC, CONEXANT R288F, G3-modulates transmit data received from a CPU
according to ITU-T V.17, V.21, V.27ter, V.29, and V.34 in transmit mode. This IC G3-
demodulates the signal received through the line according to ITU-T V.17, V.21, V.27ter,
V.29, and V.34 in receive mode. The IC detects a DTMF signal through ISDN lines.
Slave CPU
V.853 A
(IC21)
Parallel/
Serial
Conversion
(IC10)
SRAM
16Kbit
X2
(IC48,49)
Main CPU
V.821
(IC8)
Port
SW
Port
SW
Audio IC (IC45)
FUNK
(IC20)
ROM
8Mbit
(IC1)
DRAM
8Mbit
(IC41)
PCM
CODEC
(IC51)
TWINS
(IC39)
PCM
CODEC
(IC50)
SRAM
256Kbit
MODEM
R288F
(IC67)
ISDN
I/F
(IC24)
Analog
Port I/F
Port
SW
PCM
CODEC
(IC69)
MODEM
R288F
(IC52)
ISDN LINE
JACK
TWINS
DTMF Receiver
(IC38)
Audio IC (IC46)
T1
T2
Not mount
SCNT
PSU
G4
Relay
PC/DC
-12V
+5V
+5/+12/+24V
Speaker
Driver
Speaker