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PN 88300150
7.3.2 DIP-Switches #13 - #16
Switches #13 and #14 - Speed Selection
DIP-Switches #13 and #14 are used for speed selection (mainly in call origination leased line
applications).
28800 bps Operation
19200 bps Operation
14400 bps Operation
9600 bps Operation
NOTE: The modem baud rate command, $MB, overrides the setting of DIP-Switches #13 - #14.
Switch #15
Carrier Detect/DSR Source - "DSR"
(Asynchronous/Synchronous Mode/Dial-Up/Leased Line)
Some terminals react in unusual ways to the toggling of the Carrier Detect (CD - RS232C/V.24 pin 6)
signals. The most common symptom is that the modem will not respond to commands, or will not echo
characters. In these cases, force these two signals On in order for the terminal to communicate properly
with the modem when the modem is in Command mode by placing DIP-Switch #15 in the DOWN
position. With Switch #15 UP, the state of the CD and DSR signals depend on the On-Line status.
CD and DSR normal
CD and DSR forced On = Switch #15 DOWN
(Factory Default Setting = UP)
Switch #16
2-Wire/4-Wire Leased Line
(Asynchronous/Synchronous Mode/Leased Line)
2-Wire Leased Line = Switch #16 UP
4-Wire Leased Line = Switch #16 DOWN
(Factory Default Setting = DOWN)
7.4
Jumper Settings
The MT2834MR has three two-position jumpers (one for each modem) for OOS and service. Each set of
OOS jumpers defines pin 25 of the RS232C/D interface as an input (OOS) or an output (Test Mode) for
one of the three modems. Each is set to a default of OOS (U.S.); international models have a default
setting of Test Mode.
There is also a factory-set selection for MI/MIC (modified dial-up phone line interface that allows dialing
by an external device such as an 801 Dialer, computer or PBX/CBX system dialer).
7.4.1 ATEST/AV54 Jumper (S105)
Jumper S105 sets pin 25 of Modem A as input (OOS) for the default and output (Test Mode) as the option
setting on domestic (US) modems. On international modems, Jumper S105 sets pin 25 of Modem A as
input (OOS) for the option, and output (Test Mode) as the default setting. The location of these jumpers
can be seen in Figure 7-1 on the right-hand side of the board.
4/3/01
DIP-Switch
#13
#14
UP
UP
#13
#14
DOWN UP
#13
#14
UP DOWN
#13
#14
DOWN DOWN
= Switch #15 UP
71
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