Samsung SF4500, Руководство по обслуживанию

Страница: 55 / 130

6-24 Samsung Electronics
6-1-7 FAX Transceiver
6-1-7-1. GENERAL
This circuit processes transmission signals of modem
and between LIU and modem.
This circuit is added only to SmartJet 2000,
S F - 4 3 0 0 C .
6-1-7-2. MODEM (U15)
K S 1 6 117 is a single chip fax modem. It has functions
of DTMF detection and DTMF signal production
as well as functions of modem. TX OUT is
transmission output port and RX IN is received data
input port. /POR signal controlled by MFP
c o n t roller (U16:KS32C6200) can initialize
modem(/RST_OUT) without turning off the system.
D0 - D7 are 8-bit data buses. RS0 - RS4 signals to
select the register in modem decide the mode. /CS is
a
signal to select modem chips. /RD and /WR signals
c o n t rol READ and WRITE re s p e c t i v e l y. /IRQ is a sig-
nal for modem interrupt.
Transmission speed of KS16117 is supported up to
1 4 . 4 k .
6-1-7-3. TRANSMITTER
This circuit processes transmission output, analog
signal of modem(KS16117).
Output signal in each mode goes out of modem
( T X O U T:U15-44). After D/Asignals are smoothed
and filtered through active filter (U12-2), they are
b u ff e red under OPAMP(U12-6) and put out to LINE
t h rough LIU board .
6-1-7-4. RECEIVER
In the receiving mode, analog signals coming in
t h rough LIU board are amplified at OP A M P
(U13-6), and then transmitted to input terminal of
modem (RXIN:U15-45) through smoothing filter
( U 1 3 - 2 ) .
Fig.6-1-18. FAX TRANSCEIVER
FAX T R A N S M I S S I O N
U 1 2
U 1 3
FAX RECEPTION
M O D E M
K S 1 6 11 7
( U 1 5 )
LIU