Brother MFC-9420CN Service Manual page 332

Selector
No.
1 EP* tone prefix
Overseas communications
2
mode (Reception)
Overseas communications
3
mode (Transmission)
Min. time length from
4
reception of CFR to start of
5
transmission of video signals
At CNG detection, elimination
6
of chattering noise
7
(Not used.)
8 Limitation on CNG detection
NOTE: Selectors 6 and 7 are applicable to models equipped with SDAA circuits.
Selector 1: EP tone prefix
Setting this selector to "1" makes the machine transmit a 1700 Hz echo protection (EP) tone
immediately preceding training in V.29 modulation system to prevent omission of training signals.
Prefixing an EP tone is useful when the machine fails to transmit at the V.29 modem speed and
always has to fall back to 4800 bps transmission.
The setting made by this selector takes effect only when the Overseas Mode is set to ON.
Selectors 2 and 3: Overseas communications mode
These selectors should be used if the machine malfunctions in overseas communications.
According to the communications error state, select the signal specifications.
Setting selector 2 to "1" allows the machine to use 1100 Hz CED signal instead of 2100 Hz in
receiving operation. This prevents malfunctions resulting from echoes, since the 1100 Hz signal
does not disable the echo suppressor (ES) while the 2100 Hz signal does.
Setting selector 3 to "1" allows the machine to ignore a DIS signal sent from the called station
once in sending operation. This operation suppresses echoes since the first DIS signal
immediately follows a 2100 Hz CED (which disables the ES) so that it is likely to be affected by
echoes in the disabled ES state. However, such a disabled ES state will be removed soon so that
the second and the following DIS signals are not susceptible to data distortion due to echoes. Note
that some models when called may cause error by receiving a self-outputted DIS.
The setting made by selector 3 takes effect only when the Overseas Communications Mode is set
to ON. (The setting made by selector 2 is always effective.)
WSW20
(Overseas communications mode setting)
Function
No. 4
App. 4-24
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Setting and Specifications
0: OFF 1: ON
0: 2100 Hz 1: 1100 Hz
0: OFF 1: Ignores DIS once.
5
0 0 : 100 ms
0 1 : 200 ms
1 0 : 300 ms
1 1 : 400 ms
No. 6 7
0 0 : Yes, at both ON/OFF timings
0 1 : Yes, at OFF timing
1 X : No
0: OFF 1: ON
* EP: Echo protection
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