Brother MFC260C Service Manual page 400

Selector
No.
1 EP* tone prefix
Overseas communications mode
2
(Reception)
Overseas communications mode
3
(Transmission)
Min. time length from reception
4
of CFR to start of transmission
5
of video signals
6 At CNG detection, elimination
7
of chattering noise
8 Limitation on CNG detection
NOTE: Selectors 6 and 7 are applicable to models equipped with an SDAA circuit.
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 4,800 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
App. 4-24
Setting and Specifications
0: OFF
0: 2100 Hz
0: OFF
No. 4 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 0 : No
1 1 : No
0: OFF
1: ON
1: 1100 Hz
1: Ignores DIS once.
1: ON
ms: millisecond(s)
* EP: Echo protection
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