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VARMODEM 2400
U.S. ROBOTICS, INC.
VARMODEM 2400
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Modem Type
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Data (synchronous/asynchronous)
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Maximum Data Rate
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2400bps
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Data Bus
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8-bit ISA
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Data Modulation Protocol
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Bell 103A/212A
ITU-T V.21, V.22, V.22bis, V.23
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CONNECTIONS
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Purpose
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Location
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Purpose
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Location
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Line out
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CN1
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Volume
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SW2
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Line in
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CN2
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BASE I/O ADDRESS SELECTION
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Port
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J3
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J4
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» COM1: (3F8h)
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Off
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Pins 2 & 3 closed
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COM2: (2F8h)
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On
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Pins 2 & 3 closed
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COM3: (3E8h)
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Off
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Pins 1 & 2 closed
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COM4: (2E8h)
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On
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Pins 1 & 2 closed
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INTERRUPT SELECTION
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IRQ
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J5
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» 4
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Pins 1 & 2 closed
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3
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Pins 2 & 3 closed
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DTR SIGNAL
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Setting
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SW1/1
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» On
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DTR forced high
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Off
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DTR normal
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RESULT CODES
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Setting
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SW1/2
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» Off
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Verbal result codes enabled
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On
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Numeric result codes enabled
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RESULT CODES DISPLAY
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Setting
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SW1/3
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Off
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Display disabled
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» On
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Display enabled
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ECHO COMMANDS DISPLAY
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Setting
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SW1/4
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» Off
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Local echo enabled
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On
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Local echo disabled
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AUTO ANSWER
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Setting
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SW1/5
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» On
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Modem does not answer on first ring
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Off
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Modem answers on first ring
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CARRIER DETECT
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Setting
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SW1/6
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» Off
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CD normal
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On
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CD forced high
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MULTI-LINE INSTALLATION
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Setting
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SW1/7
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» Off
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Single phone connected
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On
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Multiple phones connected
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AT COMMAND SET
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Setting
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SW1/8
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» On
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AT command set recognized
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Off
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AT command set disabled
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ESCAPE CODE
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Setting
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SW1/9
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» On
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Go to command mode and display OK result code when escape character is received
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Off
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Disconnect, go to command mode and display NO CARRIER when escape character is received
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VOLUME CONTROL
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Setting
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SW1/10
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» Off
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High volume
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On
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Low volume
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Proprietary AT Command Set
See document V1254 for a full command summary.
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