d-Color MF4003/MF3303
P THEORY OF OPERATION > 8. FK-517
P-102
Transmitting modem
Receiving m
odem
Main channel data
Sh ALT
8T
16T an
d more
70 ± 5 ms
E con
trol channel data
ALT
E
con
trol channel data
24T
Bet
ween 16T and 120T
120T or less
Sh
Sh
Sh
24T
8T
Main channel re-synchronization procedure and Turn-off
• The receiving modem re-synchronizes the main channel by using the PP signal. After B1, starts receiving Primary Data.
• The transmitting modem sends the scrambled 1’s for 35 ms after Primary Data transmission has been completed.
• Both modems move to the control channel re-synchronization procedure or the control channel startup procedure.
S Signal which sends alternately 0 point and a point which rotated 0 point counterclockwise by 90 degrees
Signal which sends alternately a point which rotated 0 point counterclockwise by 180 degrees and a point which rotated 0
point counterclockwise by 270 degrees
PP Special for adjusting an equalizer
B1 High-speed signal of one frame length which is sent at the end of a series of startup sequence in the selected modulation
parameter.
Transmitting modem
Receiving m
odem
Control channel data
S PP
16T
Turn-off
35 ms
70 ± 5 ms
B1 Scrambled 1’s
S
128T
Mai
n channel
70 ± 5 ms
Control channel data
To Contro
l channel re-synchronization / Control channel startup procedure
Data
(8)Other
(a)Minimum reception signal level (RLSD) (half-duplex mode only)
• The reception circuit is turned to ON when the signal becomes 43 dBm or more.
• When the signal becomes 48 dBm or less, the reception circuit is turned OFF within 20 to 25 ms after it has exceeded the thresh old.
(b)Data frame structure
• All data transmitted in V.34 (after the Phase 4) is treated in the following frame format.
• J: The number of data frames within one super frame
• P: The number of mapping frames within one data frame
Super frame
Data
frame
Mapping frame
Four-dimensional symbol
280 ms
0
1
...
J-1
0
1
...
P-1
J=0 31 2
K=0
1
40 or 35 ms
Modulation Speed J P
2400 baud 7 12
2743 baud 8 12
2800 baud 7 14
3000 baud 7 15
3200 baud 7 16
3429 baud 8 15
8.2FUNCTION
8.2.1Telephone function
(1)TEL/FAX switching
(a)Outline
• A function to switch telephone and FAX automatically after reception. (Depends on Country spec.)
(b)Operation
1. When CNG is not detected for 2 seconds (or 4 seconds, following address parameter) after line seizure, this function sends voice
response message 1 and continues CNG detection.
2. If voice response 1 is sent and CNG detection is continued for 4 seconds but could not be detected, external ringer is sent to the
externally installed phone.
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