Service manual
Bit Switches
SM 91 M381
Fax Option
Type SP5200
(M381)
2-3
PSTN cable equalizer
(rx mode: Internal)
Bit 3: 0, Bit 2: 0 = None
Bit 3: 0, Bit 2: 1 = Low
Bit 3: 1, Bit 2: 0 = Medium
Bit 3: 1, Bit 2: 1 = High
Use a higher setting if there is signal loss at higher
frequencies because of the length of wire between the
modem and the telephone exchange.
Also, try using the cable equalizer if one or more of the
following symptoms occurs.
Communication error with error codes such as
0-20, 0-23, etc.
Modem rate fallback occurs frequently.
This setting is not effective in V.34
communications.
4
PSTN cable equalizer
(rx mode: External)
0: Disabled
1: Enabled
Keep this bit at "1".
This setting is not effective in V.34
communications.
5
Not used
Do not change the settings.
6
Parameter selection for
dial tone
detection
0: Normal parameter
1: Specific parameter
0: This uses the fixed table in the ROM for dial tone
detection.
1: This uses the specific parameter adjusted with
SRAM (69ECBEH - 69ECDEH). Select this if the dial
tone cannot be detected when the "Normal parameter:
0" is selected.
7
Not used
Do not change the settings.
G3 Switch 08 - Not used (do not change the settings)
G3 Switch 09 - Not used (do not change the settings)