Service manual
FO-4700U
FO-47UC
5 – 4
(2) Image memory block
This block is composed of 2 MByte DRAM memory and 256 KByte SRAM.
Moreover, a maximum of 2 MByte (when FO-1MK is installed) of image
memory can be extended by installing the option memory of the con-
nector CNOP.
1) HY5118164 or MSM5118165 (IC16) ... pin-42, 80J
The memory which the image data of the copy, transmission and recep-
tion are stored in. The capacity of 1 MByte is assigned. The rest 1 MByte
is a system memory. (Refer to the (1) Main control block)
2) W24010S-70L(IC21, IC36) ... pin-32, SOP
(1 Mbit SRAM)
The setting of receiving mode, optional setting content, soft switch con-
tent and dairy data are stored. Even if the power supply of the main
body is turned off, it is backed up with a lithium battery.
(3) Modem block
The block is mainly composed of the modem R144AFXL (IC24), and is
provided with the following modem function.
Commu- Modu-
Modu-
Transmis- ITU-T
No. nication Baud rate lation
lation rate
sion recom-
mode system frequency mendation
1G3
14400bps 128-value 2400baud 1800Hz V33, V17
TCM
2G3
12000 64-value 2400 1800 V33, V17
TCM
3G3
9600 16-value 2400 1700 V29, V17
QAM
4G3
7200 8-phase 2400 1700 V29
PSK
5G3
4800 8-phase 1600 1800 V27ter
PSK
6G3
2400 4-phase 1200 1800 V27ter
PSK
7G3
300 FSK 300 1650/ V21
1850
8G2
AM•PM• 2100 T3
VSB
In addition to the above functions, the following tone transfer/tone
detection functions are also provided.
No. Signal name Frequency
1 CED 2100Hz
2 G1 1850
3 GC 2100
4 CFR 1650
5 MCF 1650
6 LCS 1100
7 EOM 1100
8 PIS 462
No. Signal name Frequency
1 G1 1850Hz
2 CFR,MCF 1650
3 GC 2100
The above functions are controlled by getting an access to the inter-
face memory in the modem through the data bus from CPU (IC27) of
the control PWB. The interface memory is composed of 32 8-bit reg-
isters, and is controlled with the bank switch. Accordingly, the register
is selected by the register selection signals (RS4 to RS0) of 5 bits and
chip selection signal (CS). The major content controlled by these reg-
isters is as follows.
1) Configuration register
Mode setting of V17, V29, V27, G2, FSK and tone transmission.
2) Option register
Equalizing method of equalizer, carrier detection threshold, addition
of echo suppressor protect tone, and setting of transmission/recep-
tion mode.
3) Others
G2AGC control, tone frequency setting, and so on.
Moreover, data is read from these registers through the data bus to
monitor the statuses of the modem such as tone detection, training
pattern detection and so on.
Next, transmission/reception operation is described.
During sending, the sent data is given from the control block to the
modem through the data bus. Then, it is modulated and sent to LIU
PWB with SIGTX signal. During receiving, the received data is sent
from LIU PWB to the modem with SIGRX signal and is demodulated.
Then, it is sent to the control block with the data bus. The above op-
eration is done with the modem LSI (IC).