Toshiba GD-1210 Service Manual page 54

(4) Training
The training is performed in the binary procedure to surely transmit the image signals.
• Training signal
The training signal is transmitted following the DCS signal at the modem speed specified by
the DCS signal. Responding to this training signal, the receiving side adjusts the auto-equal-
izer.
• Format of the training signal
- 14.4 Kbps, 12 Kbps
Segment 1
Alternation
of ABAB
106 msec
- 9600 bps, 7200 bps
Segment 1
V.29 No signal
20 msec
- 4800 bps, 2400 bps
Segment 1Segment 2
Non-
V.27ter modulated
carrier
• TCF signal
An error may occur in the image data if the training is not performed correctly. The transmit-
ting side sends a TCF signal and checks if any error occurs in image data before the image
data communication to follow. When the receiving side detects an error in the TCF signal, it
transmits an FTT signal to the transmitting side to request the retraining. When there is no
error, the receiving side transmits a CFR signal.
The TCF signal transmits all zeros for 1.5 seconds at the same modem speed as that for the
training signal.
GD-1210/1250/1270/1160/1260
DIALING/COMMUNICATION CONTROL
Segment 2 Segment 3
Equalizer Chain-store
adjustment information
pattern sequence
1240 msec 27 msec
1393 msec
Segment 2 / Segment 3
Repeating 2-state
signal
( Binary )
53 msec+160 msec
253 msec
Segment 3
Continuous
180° phase
No signal
inversion
( Binary )
4,800 bps: 923 msec,
2,400 bps: 1158 msec
Segment 4
Scrambled binary data "1"
20 msec
Fig. 3-4
Segment 4
Scrambled data "1"
( Hexa or octal )
20 msec
Fig. 3-5
Segment 4 Segment 5
0° to 180°
2-phase pattern Scrambled data "1"
( Binary )
Fig. 3-6
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TCF
TCF
TCF
( Hexa or octal)