Wsw20 (Overseas Communications Mode Setting) - Ricoh G157 Service Manual

MAINTENANCE MODE

WSW20 (Overseas communications mode setting)

Selector
No.
1 EP (Echo protection) tone prefix
Overseas communications mode
2
(Reception)
Overseas communications mode
3
(Transmission)
Min. time length from reception of
4, 5 CFR to start of transmission of
video signals
At CNG detection, elimination of
6, 7
chattering noise (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.)
G157
Function
5-62
Setting and Specifications
0: OFF
0: 2100 Hz
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
No. 6. 7.
0 0: 100 ms
0 1: 200 ms
1 0: 300 ms
1 1: 400 ms
0: OFF
1: ON
1: 1100Hz
1: ON
SM