Model III Ports related to MODEM operation
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           Luis M. Garcia-Barrio

PORT E8H (232): Master Reset/MODEM Status Register.
Any output to this port resets the Controller.
On input:   Bit 4 -- Ring Indicator
            Bit 5 -- Carrier Detect
            Bit 6 -- Data Set Ready
            Bit 7 -- Clear To Send

PORT E9H (233): Config. DIP switches/Baud rate select
On input:   Bits 0-2 Baud rate from 50 to 1200
                     5=300; 7=1200
            Bit 3 -- 0=Parity On; 1=Parity Off
            Bit 4 -- 0=1 Stop Bit; 1=2 Stop Bits
            Bit 5-6  Word length.
                     00=5, 01=6, 10=7, 11=8
            Bit 7 -- 0=Parity Odd; 1=Parity Even
On output   Bits 0-3 Receive Baud Rate (50-19200)
            Bits 4-7 Transmit Baud Rate (50-19200)

PORT EAH (234): Status and Control Register
On input:   Bit 3 -- 1=Parity Error
            Bit 4 -- 1=Framing Error
            Bit 5 -- 1=Overrun Error
            Bit 6 -- 1=Data Sent
            Bit 7 -- 1=Data Ready
On output   Bit 0 -- Data Terminal Ready
            Bit 1 -- Request To Send
            Bit 2 -- Break
            Bit 3 -- Parity enable
            Bit 4 -- Stop bits
            Bits 5-6 Word length select 
            Bit 7 -- Parity

PORT EBH (235): Data Register
On input:   Received Data
On output:  Transmit Data