Brother MFC990CW Service Manual page 480

Selector
No.
Starting point of training check
1
(TCF)
2
Allowable training error rate
3
4
Decoding error rate for
transmission of RTN
5
6
Not used.
7
8 Limitation of attenuation level
Note: Selector 8 is not applicable to the French models.
• Selector 1: Starting point of training check (TCF)
At the training phase of receiving operation, the called station detects for 1.0 second a
training check (TCF) command, a series of zeros which is sent from the calling station for
1.5 seconds to verify training and give the first indication of the acceptability of the line.
This selector sets the starting point from which the called station should start counting
those zeros. If this selector is set to "0," the called station starts counting zeros 100
milliseconds after the head of a series of zeros is detected.
If it is set to "1," the called station starts counting zeros upon detection of 10-millisecond
successive zeros 50 milliseconds after the head of a series of zeros is detected. In this case,
if the detection of 10-millisecond successive zeros is too late, the data counting period will
become less than 1.0 second, making the called station judge the line condition
unacceptable.
• Selectors 2 and 3: Allowable training error rate
The called station checks a series of zeros gathered in training (as described in Selector 1)
according to the allowable training error rate set by these selectors. If the called station
judges the line condition to be accepted, it responds with CFR; if not, it responds with FTT.
• Selectors 4 and 5: Decoding error rate for transmission of RTN
The machine checks the actual decoding errors and then transmits an RTN according to the
decoding error rate (Number of lines containing an error per page ÷ Total number of lines
per page) set by these selectors.
• Selector 8: Limitation of attenuation level
Setting this selector to "0" limits the transmitting level of the modem to 10 dB (1 dB in
France).
This setting has priority over the settings selected by WSW02 (selectors 5 through 8) and
WSW13 (selectors 5 through 8).
WSW23
(Communications setting)
Function
App. 4-28
Setting and Specifications
0: From the head of a series of zeros
1: From any arbitrary point
No. 2 3
0 0 : 0%
0 1 : 0.5%
1 0 : 1%
1 1 : 2%
No. 4 5
0 0 : 16%
0 1 : 14%
1 0 : 10%
1 1 : 8%
0: Yes 1: No
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