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1200/300 BAUD MODEM
UNIDENTIFIED
1200/300 BAUD MODEM
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Modem Type
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Data (synchronous/asynchronous)
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Maximum Data Rate
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1200bps
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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 103 & 212A, ITU-T V.22
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Error Correction/Compression
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Unidentified
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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-in
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J1
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Line-out
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J2
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INTERRUPT SELECT - JP1
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í IRQ
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Jumper A
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Jumper B
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Jumper C
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Jumper D
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» IRQ4
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Open
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Open
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Closed
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Open
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í IRQ2
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Closed
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Open
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Open
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Open
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í IRQ3
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Open
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Closed
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Open
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Open
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í IRQ5
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Open
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Open
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Open
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Closed
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ADDRESS SELECT
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í COM/Address
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SW1/1
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SW1/2
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» COM1/3F8h
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Off
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Off
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í COM2/2F8h
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Off
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On
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í COM3/3E8h
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On
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Off
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í COM4/2E8h
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On
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On
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RECEIVED LINE SIGNAL DETECT BIT (RLSD)
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í Setting
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SW1/3
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» RLSD bit reset/carrier detect status written to modem status register.
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Off
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í RLSD bit written to modem status register.
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On
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DATA TERMINAL READY (DTR)
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í Setting
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SW1/4
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» DTR bit status written to the UART modem control register.
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Off
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í DTR bit is ignored.
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On
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PROTOCOL SELECT
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Protocol
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SW1/5
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» Bell 103 & 212A enabled.
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Off
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í CCITT V.22 enabled.
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On
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MAKE/BREAK RATIO
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í Setting
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SW1/6
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» 39/61 ratio (Bell standard).
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Off
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í 33/67 ratio (CCITT standard).
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On
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