< WSW20 >

 

Selector No.

Function

 

Setting and Specifications

 

 

 

 

 

 

 

1

 

EP* tone prefix

0: OFF

1: ON

 

 

 

 

 

 

 

 

2

 

Overseas communications

0: 2100 Hz

1: 1100 Hz

 

 

mode (Reception)

 

 

 

 

 

 

 

3

 

Overseas communications

0: OFF

1: Ignores DIS once.

 

 

mode (Transmission)

 

 

 

 

 

 

 

 

 

 

No. 4

5

 

 

4

 

Min. time length from reception

0

0: 100 ms

 

 

 

of CFR to start of transmission

0

1: 200 ms

 

 

5

 

 

 

 

of video signals

1

0: 300 ms

 

 

 

 

 

 

 

 

 

1

1: 400 ms

 

 

 

 

 

No. 6

7

 

 

6

 

At CNG detection, elimination of

0

0: Yes, at both ON/OFF timings

 

 

0

1: Yes, at OFF timing

 

7

 

chattering noise

 

 

1

0: No

 

 

 

 

 

 

 

 

 

 

1

1: No

 

 

 

 

 

 

 

 

8

 

Limitation on CNG detection

0: OFF

1: ON

 

 

 

 

 

 

 

* EP: Echo protection

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.)

App. 1-25

Confidential