Ricoh A250 Service Manual page 510

BIT SWITCHES
4 Modem types available for
to reception
7 Bit 7 6 5 4 Setting
0 0 0 1 V.27ter
0 0 1 0 V.27ter, V.29
0 0 1 1 V.27ter, V.29
0 1 0 0 V.27ter, V.29,
0 1 0 1 V.27ter, V.29,
Other settings - Not used
G3 Switch 07
No FUNCTION
0
PSTN cable equalizer
to (tx mode: Internal)
1 Bit 1 Bit 0
0 0
0 1
1 0
1 1
2 PSTN cable equalizer
to (rx mode: Internal)
3 Bit 3 Bit 2
0 0
0 1
1 0
1 1
4 PSTN cable equalizer
(V.8/V.17 rx mode: External)
0: Disabled
1: Enabled
5 PSTN cable equalizer
(V.34 rx mode; External)
6-7 Not used
A250
The setting of these bits is used to inform the
transmitting terminal of the available modem type
for the machine in receive mode.
If V.34 is not selected, V.8 protocol must be
disabled manually.
V.33
Cross reference
V.17/V.33
V.8 protocol on/off - G3 switch 03, bit2
V.17/V33,
V.34
Use a higher setting if there is signal loss at
higher frequencies because of the length of wire
Setting between the modem and the telephone
None exchange.
Low Use the dedicated transmission parameters for
Medium specific receivers.
High
Also, try using the cable equalizer if one or more
of the following symptoms occurs.
•
•
Note: This setting is not effective in V.34
communications.
Use a higher setting if there is signal loss at
higher frequencies because of the length of wire
Setting between the modem and the telephone
None exchange.
Low
Medium Also, try using the cable equalizer if one or more
High of the following symptoms occurs.
•
•
Note: This setting is not effective in V.34
communications.
Keep this bit at "1".
Keep this bit at "1".
Do not change the settings.
COMMENTS
Communication error
Modem rate fallback occurs frequently.
Communication error with error codes such as
0-20, 0-23, etc.
Modem rate fallback occurs frequently.
4-48 SM