Dual Port Serial Board  (250-4039)   Settings          Faxback Doc. # 5490

This board has two DB-9 male serial port connections

    Serial Port #1
────────┬──────────┬───────────┬───────────┐
Port    │  Switch  │ Interrupt │           │
        │ Settings │  Jumpers  │ Address   │
────────┼──────────┼───────────┼───────────│
COM1:   │ 1 2 3 4  │  1 2 3 4  │           │
Sw  ON  │ X X      │      X    │  3F8-3FF  │
Sw  OFF │          │   IRQ 4   │           │
────────┼──────────┼───────────┼───────────│
COM2:   │ 1 2 3 4  │  1 2 3 4  │           │
Sw  ON  │ X        │    X      │  2F8-2FF  │
Sw  OFF │   X      │   IRQ 3   │           │
────────┼──────────┼───────────┼───────────│
COM3:   │ 1 2 3 4  │  1 2 3 4  │           │
Sw  ON  │   X      │  X   X    │  3E8-3EF  │
Sw  OFF │ X        │ IRQ2 IRQ4 │           │CAN USE EITHER IRQ4 OR IRQ2)
────────┼──────────┼───────────┼───────────│
COM4:   │ 1 2 3 4  │  1 2 3 4  │           │
Sw  ON  │          │    X   X  │  2E8-2EF  │
Sw  OFF │ X X      │ IRQ3 IRQ5 │           │CAN USE EITHER IRQ3 OR IRQ5)
 ───────┴──────────┴───────────┴───────────┘
                               
        Serial Port #2
────────┬──────────┬───────────┬───────────┐
Port    │  Switch  │ Interrupt │           │
        │ Settings │  Jumpers  │ Address   │
────────┼──────────┼───────────┼───────────│
COM1:   │ 1 2 3 4  │  1 2 3 4  │           │
Sw  ON  │     X X  │      X    │  3F8-3FF  │
Sw  OFF │          │   IRQ 4   │           │
────────┼──────────┼───────────┼───────────│
COM2:   │ 1 2 3 4  │  1 2 3 4  │           │
Sw  ON  │     X    │    X      │  2F8-2FF  │
Sw  OFF │       X  │   IRQ 3   │           │
────────┼──────────┼───────────┼───────────│
COM3:   │ 1 2 3 4  │  1 2 3 4  │           │
Sw  ON  │       X  │  X   X    │  3E8-3EF  │
Sw  OFF │     X    │ IRQ2 IRQ4 │           │(CAN USE EITHER IRQ4 OR IRQ2)
────────┼──────────┼───────────┼───────────│
COM4:   │ 1 2 3 4  │  1 2 3 4  │           │
Sw  ON  │          │    X   X  │  2E8-2EF  │
Sw  OFF │     X X  │ IRQ3 IRQ5 │           │(CAN USE EITHER IRQ3 OR IRQ5)
────────┴──────────┴───────────┴───────────┘
+5/Ring Indicator Jumpers


Two jumpers (W1 and W2) are provided on the Dual Port Serial Board to
replace the ring indicator signal with +5 volts. This can provide power
for a serial driven mouse. Jumper W1 provides +5 Volts for Serial #2.
The jumper settings are the same for both serial ports. Refer to the
following diagram.

    L R        L R
    X            X
    X            X
Ring Indicator      +5 Volts
Signal Setting      Setting*

*This jumper setting will cause the Dual Port Serial Board to fail the 
diagnostic serial port test.

"D"
 PIN Signal                       Direction

 1  CD-Carrier Detect             To Dual Port Serial Board
 2  RD-Receive Data               To Dual Port Serial Board
 3  TD-Transmit Data              From Dual Port Serial Board
 4  DTR-Data Terminal Ready       From Dual Port Serial Board
 5  Ground
 6  DSR-Data Set Ready            To Dual Port Serial Board
 7  RTS-Request To Send           From Dual Port Serial Board
 8  CTS-Clear To Send             To Dual Port Serial Board
 9  +5/RI-Ring Indicator          To Dual Port Serial Board

*NOTE*
The UART chip on the board will not keep up with the faster speed of the
T3000 and T4000 models.  Check the UART, if the chip is an 8250, the chip
should be replaced with an NS16450.  You can order the correct chip from
National Parts under catalog number 25-4011, part MX-6981.

This board is labeled on the board for dip switch settings.

The Dual Port Serial Board does not support the 20mA current loop.

Some application software will support will support COM3: and COM4:, but
you must specify the address and interrupt to be used in the software
package.

(smm/jej-05/12/94)