Ricoh D072 Service Manual page 595

Bit Switches
PSTN cable equalizer
(rx mode: Internal)
Bit 3: 0, Bit 2: 0 = None
2-3
Bit 3: 0, Bit 2: 1 = Low
Bit 3: 1, Bit 2: 0 = Medium
Bit 3: 1, Bit 2: 1 = High
PSTN cable equalizer
(V.8/V.17 rx mode: External)
4
0: Disabled
1: Enabled
5 Not used
Parameter selection for dial
tone detection
6
0: Normal parameter
1: Specific parameter
7
Not used
G3 Switch 08 - Not used (do not change the settings)
G3 Switch 09 - Not used (do not change the settings)
D067/D068/D069/D072
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
communicatio
Keep this bit at "1".
Do not change the settings.
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.
Do not change the settings.
7-56 SM Appendix