Brother FAX-270MC, Service Manual

Page: 120 / 220

V – 32
WSW20
(Overseas communications mode setting)
Function
Selector
No.
Overseas communications mode
(Transmission)
Setting and Specifications
1
EP* tone prefix
0: OFF 1: ON
2 0: 2100 Hz 1: 1100 Hz
Overseas communications mode
(Reception)
3 0: OFF 1: Ignores DIS once.
No. 4 5
0 0 : 100 ms
0 1 : 200 ms
1 0 : 300 ms
1 1 : 400 ms
4
5
Min. time length from reception
of CFR to start of transmission of
video signals
No. 6 7
0 0 : A (During CNG ON and OFF)
0 1 : B (During CNG OFF only)
1 X : C (No elimination)
6
7
Chattering elimination for CNG
detection
8
* EP: Echo protection
●
Selector 1: EP tone prefix
Setting this selector to "1" makes the equipment transmit a 1700 Hz echo protection (EP)
tone immediately preceding training in V.29 modulation system to prevent omission of train-
ing signals.
Prefixing an EP tone is effective when the equipment fails to transmit at the V.29 modem
speed and always has to fall back to 4800 bps transmission.
●
Selectors 2 and 3: Overseas communications mode
These selectors should be used if the facsimile equipment malfunctions in overseas commu-
nications. According to the communications error state, select the signal specifications.
Setting selector 2 to "1" allows the equipment 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 equipment to ignore a DIS signal sent from the called
station once in sending operation. This operation suppresses echoes since the first DIS sig-
nal immediately follows a 2100 Hz CED (which disables the ES) so that it is likely to be af-
fected by echoes in the disabled ES state. However, such a disabled ES state will be re-
moved 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.
●
Selector 8: CNG detection on/off
If this selector is set to “1,” the equipment detects a CNG signal according to the condition
preset by selectors 2 and 4 of WSW18 after a line is connected. If it is set to “0,” the equip-
ment detects a CNG signal as long as a line is connected.
CNG detection on/off 0: OFF 1: ON