Card Type	Serial
Chip Set	Zilog
I/O Options	Serial ports (2)
Data Bus	8-bit ISA

CONNECTIONS
Function	Label	Function	Label
Serial port 1 (May be RS-232, RS-422/423, or RS-485)	J1	Serial port 2 (RS-232 only)	J2

USER CONFIGURABLE SETTINGS
Setting		Label	Position
»	Factory configured - do not alter	SW1/1	Off

CLOCK SOURCE FOR PORT 1
Setting	JB3
External clock from serial RTxC	Pins 1 & 2 closed
Internal clock from 8254	Pins 1 & 3, 2 & 4 closed

DMA CHANNEL - RECEIVE
Setting	JB1
DMA1	Pins 9 & 10, 13 & 14 closed
DMA3	Pins 10 & 12, 14 & 16 closed
Disabled	Above pins open

DMA CHANNEL - TRANSMIT
Setting	JB1
DMA1	Pins 9 & 11, 13 & 15 closed
DMA3	Pins 11 & 12, 15 & 16 closed
Disabled	Above pins open
Note: If a DMA is used for transmission then port 1 may not be used.

BASE I/O ADDRESS
Setting		SW1/2	SW1/3	SW1/4	SW1/5	SW1/6	SW1/7	SW1/8
	000h	On	On	On	On	On	On	On
	008h	On	On	On	On	On	On	Off
	010h	On	On	On	On	On	Off	On
	018h	On	On	On	On	On	Off	Off
	020h	On	On	On	On	Off	On	On
»	380h	Off	Off	Off	On	On	On	On
	3D8h	Off	Off	Off	Off	On	Off	Off
	3E0h	Off	Off	Off	Off	Off	On	On
	3E8h	Off	Off	Off	Off	Off	On	Off
	3F0h	Off	Off	Off	Off	Off	Off	On
	3F8h	Off	Off	Off	Off	Off	Off	Off
Note: A total of 127 base address settings are available. The switches are a binary representation of the decimal memory addresses. SW1/2 is the Most Significant Bit and switch SW1/8 is the Least Significant Bit. The switches have the following decimal values: SW1/8=8, SW1/7=16, SW1/6=32, SW1/5=64, SW1/4=128, SW1/3=256, SW1/2=512. Turn off the switches and add the values of the switches that are off to obtain the correct memory address. (Off=1, On=0)

INTERRUPT
Setting	JB1
IRQ3 internally	Pins 1 & 2 closed
IRQ3 from 8254	Pins 1 & 3 closed
IRQ4 internally	Pins 2 & 4 closed
IRQ4 from 8254	Pins 3 & 4 closed
IRQ5 internally	Pins 5 & 6 closed
IRQ5 from 8254	Pins 5 & 7 closed
IRQ7 internally	Pins 6 & 8 closed
IRQ7 from 8254	Pins 7 & 8 closed

PORT 1 TYPE
Setting	JB4	U5	U6	U9	U10
RS-232	Pins 1 & 2, 4 & 5 open	Not installed	MC1489	Not installed	MC1488
RS-422/423	Pins 1 & 2, 4 & 5 open	26LS32	Not installed	26LS31	Not installed
RS-485	Pins 1 & 2, 4 & 5 closed	26LS32	Not installed	26LS31	Not installed

PORT 1 PINS 9 & 10
Setting	JB3
+12V DC	Pins 7 & 8 closed
Not used	Pins 7 & 8 open

PORT 1 RS-422/423/485 DRIVER
Setting	JB3
Enabled by RTS	Pins 5 & 6 closed
Enabled permanently	Pins 3 & 5 closed

PORT 1 RS-422/423 DRIVER TERMINATION
Setting	JB4	RP3	RP4
Not terminated	Pins 5 & 6, 7 & 8 closed	Not installed	Not installed
Terminated	Pins 5 & 7, 6 & 8 closed	Installed	Installed
Note: The ohm values of RP3 and RP4 should be determined to cause a difference in voltage of at least 2.0V between the ends of the serial cable.

8254 CLK0 SOURCE
Setting	JB2
8254 clock signal	Pins 15 & 16 closed
Disabled	Pins 15 & 16 open

8254 CLK1 SOURCE
Setting	JB2
8254 clock signal	Pins 13 & 14 closed
8254 CLK0	Pins 11 & 13 closed
Disabled	Above pins open

8254 CLK2 SOURCE
Setting	JB2
8254 clock signal	Pins 10 & 12 closed
8254 CLK1	Pins 9 & 10 closed
Disabled	Above pins open

CLK0 INTERRUPT GENERATOR
Setting	JB2
CLK0 generates interrupt	Pins 7 & 8 closed
CLK0 does not generate interrupt	Pins 7 & 8 open

CLK1 INTERRUPT GENERATOR
Setting	JB2
CLK1 generates interrupt	Pins 5 & 6 closed
CLK1 does not generate interrupt	Pins 4 & 6 open

CLK2 INTERRUPT GENERATOR
Setting	JB2
CLK2 generates interrupt	Pins 1 & 3 closed
CLK2 does not generate interrupt	Pins 1 & 2 open

MISCELLANEOUS TECHNICAL NOTE

When using RS-422, resistors R2, R3, R5, and R6 must be installed to match the impedance of the cable that is used. The board will not function properly in RS-422 mode without these resistors.