Sharp FO-DC600, Service Manual, Page: 82 / 150

FO-DC600U
[7] Circuit description of Dual Line Kit (Option: FO-60DL)
1) Block diagram
SURGE
PROTECTION
CIRCUIT
DIODE
BRIDGE
ACTIVE
CHOKE
HI
LO
CI
DETECTOR
+5V
TXA2
MODEM
(FM336PLUS)
RIN
SPKR
TXA1
VREF
RXIN RXIN
TXOUT
DUAL LINE
CONTROL
LIU (LINE-2)
HI
XCI1 XCI1
CML1 CML1 CML1
XCI1
SUB ASIC
LO
TXOUT
LINE-2
5 – 20
Fig. 13
2) Circuit description
1. Dual Line Control PWB
2. LIU PWB (Line-2)
1. Dual Line Control PWB
The circuit structure of Dual Line Control PWB is the same as that of
Modem Block on the Control PWB, and has G3 FAX communication
function which is similar to that function of Line-1.
2. LIU PWB (Line-2)
LIU PWB (Line-2) is the same unit as LIU PWB (Line-1) and has line
I/F function for Line-2.
It is controlled by Control PWB, and the communication data line is
connected to the modem on Dual Line Control PWB.