Processor	80486SX/80487SX/80486DX/ODP486SX/80486DX2
Processor Speed	16/20/25/33/50(internal)/66(internal)MHz
Chip Set	OPTI
Max. onboard DRAM	6MB (82C495 AT U77) OR 18MB (82C495B1 AT U77)
Cache	64/128/256KB
BIOS	Phoenix
Dimensions	330mm x 218mm
I/O Options	Fax/modem daughterboard, floppy drive interface, game port, IDE interface, multi-function connector (IDE interface LED, keylock, reset, SW_MODLR, Turbo LED), parallel port, PS/2 keyboard port, PS/2 mouse port, serial port, VGA feature connector, VGA port
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
PS/2 keyboard	J1	Keyboard lock	J19
PS/2 mouse	J2	Fax/modem daughterboard	J21
VGA port	J3	IDE interface	J25
Game port	J4	Floppy drive interface	J27
Parallel port	J5	External speaker connector	J28
Serial port B	J6	Multi-function connector	J32
External battery	J7	CPU/chassis fan power (+12VDC)	J33
VGA feature connector	J13	Riser card	S1

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	Internal battery enabled	J8	Closed
	Internal battery disabled	J8	Open
»	Onboard Game port enabled	J12	pins 2 & 3 closed
	Onboard Game port disabled	J12	pins 1 & 2 closed
»	Monitor type select color	J16	Closed
	Monitor type select monochrome	J16	Open
»	PS/2 mouse port enabled	J17	Closed
	PS/2 mouse port disabled	J17	Open
»	Onboard IDE interface enabled	J24	pins 1 & 2 closed
	Onboard IDE interface disabled	J24	pins 2 & 3 closed
»	Onboard floppy drive interface enabled	J26	pins 1 & 2 closed
	Onboard floppy drive interface disabled	J26	pins 2 & 3 closed
»	Onboard speaker enabled	J29	pins 1 & 2 closed
	Onboard speaker disabled	J29	pins 2 & 3 closed

DRAM CONFIGURATION
Size	Bank 0	Bank 1	Bank 2	U77
2MB	(8) 41256	(8) 41256	NONE	Either
6MB	(8) 41256	(8) 41256	(4) 1M x 9	Either
18MB	(8) 41256	(8) 41256	(4) 4M x 9	82C495B1 ONLY
Note:256K x 9 SIMMs are not supported. 18MB configuration requires OPTI 82C495B1 DRAM controller. Banks 0 and 1 are soldered to the board and should not be altered.

VIDEO CONFIGURATION
Mode	J10	J14
VGA port (J3)	pins 1 & 2 closed	Closed
VGA feature connector (J13)	pins 1 & 2 closed	Open
Disabled	pins 2 & 3 closed	N/A

VRAM CONFIGURATION
Size	Bank 0	Bank 1
512KB	(4) 44256	NONE
1024KB	(4) 44256	(4) 44256
Note:If Bank 1 sockets are omitted from board, board was factory installed with 1MB of VRAM. Bank 0 is soldered to the board and should not be altered.

SERIAL PORT CONFIGURATION
Modem (J21)	Port B (J5)	ISA Modem	J18	J20	J101/JMOD *
Disabled	COM2	None	N/A	pins 1 & 2	Closed
Disabled	COM2	COM1	pins 2 & 3	pins 1 & 2	Closed
Disabled	COM2	COM3	pins 1 & 2	pins 1 & 2	Closed
COM1	COM2	None	pins 1 & 2	pins 1 & 2	Open
COM3	COM2	None	pins 2 & 3	pins 1 & 2	Open
Disabled	COM4	None	N/A	pins 2 & 3	Closed
Disabled	COM4	COM1	pins 2 & 3	pins 2 & 3	Closed
Disabled	COM4	COM3	pins 1 & 2	pins 2 & 3	Closed
COM1	COM4	None	pins 1 & 2	pins 2 & 3	Open
COM3	COM4	None	pins 2 & 3	pins 2 & 3	Open
Note:* JMOD is a special block placed on J21, connecting pins 10 and 11 together diagonally.

PARALLEL PORT CONFIGURATION
LPT		IRQ	J22	J23
»	LPT1	IRQ7	pins 1 & 2 closed	pins 1 & 2 closed
	LPT1	IRQ5	pins 1 & 2 closed	pins 2 & 3 closed
	LPT2	IRQ7	pins 2 & 3 closed	pins 1 & 2 closed
	LPT2	IRQ5	pins 2 & 3 closed	pins 2 & 3 closed

CPU TYPE CONFIGURATION
CPU	J30/1 & 2	J30/3 & 4	J30/5 & 6	J30/7 & 8	J30/9&10	J31	J34
80486SX	Open	Closed	Open	Open	Open	Open	Open
80487SX	Closed	Open	Closed	Open	Closed	Open	Open
80486DX	Closed	Open	Closed	Closed	Open	Open	Open
ODP486SX	Closed	Open	Closed	Closed	Open	Closed	Closed
80486DX2	Closed	Open	Closed	Closed	Open	Open	Closed

CPU SPEED CONFIGURATION
Speed	J35/pins 1 & 2	J35/pins 3 & 4
16MHz	Closed	Closed
20MHz	Open	Closed
25MHz	Closed	Open
33MHz	Open	Open

CACHE CONFIGURATION
Size	Cache	Location	TAG (U81)	Dirty Bit (U84)
64KB	(8) 8K x 8	Banks 0 & 1	(1) 32K x 8	(1) 64K x 1
128KB	(4) 32K x 8	Bank 0	(1) 32K x 8	(1) 64K x 1
256KB	(8) 32K x 8	Banks 0 & 1	(1) 32K x 8	(1) 64K x 1

CACHE JUMPER CONFIGURATION
Size		J36/1 & 2	J36/3 & 4	J36/5 & 6	J36/7 & 8	J36/9 & 10
»	Disabled	Open	Open	Open	Open	Open
	64KB	Open	Open	Open	Open	Open
	128KB	Closed	Open	Closed	Closed	Open
	256KB	Closed	Closed	Closed	Open	Closed