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VESA MAINBOARD SIS 486 (REV. 2)
CHAINTECH COMPUTER COMPANY, LTD.
VESA MAINBOARD SIS 486 (REV. 2)
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Processor
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80486SX/CX486M7/80486DX/80486DX2/Pentium Overdrive
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Processor Speed
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25/33/40/50(internal)/50/66(internal)MHz
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Chip Set
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SIS
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Max. Onboard DRAM
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128MB
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Cache
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128/256/512KB
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BIOS
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AMI/Award
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Dimensions
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330mm x 218mm
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I/O Options
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32-bit VESA local bus slots (3), green PC connector
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NPU Options
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None
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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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External battery
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J1
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Reset switch
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J6
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Turbo switch
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J3
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Power LED & keylock
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J7
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Turbo LED
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J4
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Green PC connector
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JP26
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Speaker
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J5
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32-bit VESA local bus slots
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SL1 - SL3
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USER CONFIGURABLE SETTINGS
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Function
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Jumper
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Position
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»
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SMOUT type select normal mode
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J2
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Closed
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SMOUT type select standby mode
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J2
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Open
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»
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CMOS memory normal operation
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JP16
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pins 1 & 2 closed
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CMOS memory clear
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JP16
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pins 2 & 3 closed
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»
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Factory configured - do not alter
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JP18
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Open
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DRAM CONFIGURATION
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Size
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Bank 0
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Bank 1
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1MB
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(4) 256K x 9
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NONE
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2MB
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(4) 256K x 9
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(4) 256K x 9
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4MB
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(4) 1M x 9
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NONE
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5MB
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(4) 256K x 9
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(4) 1M x 9
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8MB
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(4) 1M x 9
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(4) 1M x 9
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16MB
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(4) 4M x 9
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NONE
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17MB
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(4) 256K x 9
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(4) 4M x 9
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20MB
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(4) 1M x 9
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(4) 4M x 9
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32MB
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(4) 4M x 9
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(4) 4M x 9
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64MB
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(4) 16M x 9
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NONE
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65MB
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(4) 256K x 9
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(4) 16M x 9
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68MB
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(4) 1M x 9
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(4) 16M x 9
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80MB
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(4) 4M x 9
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(4) 16M x 9
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128MB
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(4) 16M x 9
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(4) 16M x 9
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CACHE CONFIGURATION
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Size
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Bank 0
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Bank 1
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TAG
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128KB
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(4) 32K x 8
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NONE
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(1) 8K x 8
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256KB
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(4) 32K x 8
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(4) 32K x 8
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(1) 32K x 8
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512KB
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(4) 128K x 8
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NONE
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(1) 32K x 8
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CACHE JUMPER CONFIGURATION
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Size
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JP1
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JP2
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JP3
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JP4
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128KB
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pins 1 & 2 closed
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pins 1 & 2 closed
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pins 1 & 2, 3 & 4 closed
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pins 1 & 2 closed
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256KB
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pins 2 & 3 closed
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pins 2 & 3 closed
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pins 2 & 3, 4 & 5 closed
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pins 1 & 2 closed
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512KB
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pins 1 & 2 closed
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pins 2 & 3 closed
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pins 1 & 2, 3 & 4 closed
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pins 2 & 3 closed
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CPU TYPE CONFIGURATION
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Type
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JP8
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JP9
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JP10
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JP11
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JP12
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JP13
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JP14
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80486SX
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2 & 3
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Open
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2 & 3
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Open
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3 & 4
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1 & 2
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2 & 3
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CX486M7
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1 & 2
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Closed
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2 & 3
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2 & 3
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2 & 3
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Open
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1 & 2
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80486DX/DX2
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1 & 2
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Closed
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2 & 3
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2 & 3
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3 & 4
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1 & 2
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2 & 3
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P23S
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2 & 3
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Open
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2 & 3
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Open
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3 & 4
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1 & 2
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2 & 3
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P24D
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1 & 2
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Closed
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1 & 2
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2 & 3
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1 & 2
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2 & 3
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2 & 3
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P24S
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1 & 2
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Closed
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2 & 3
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2 & 3
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3 & 4
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1 & 2
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2 & 3
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P24T
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1 & 2
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Closed
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1 & 2
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1 & 2
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3 & 4
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Open
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1 & 2
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Note: Pins designated should be in the closed position.
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CPU TYPE CONFIGURATION (CON’T)
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Type
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JP15
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JP21
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JP22
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JP24
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JP25
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JP30
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80486SX
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4 & 5
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2 & 3
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1 & 2
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Open
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Open
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Open
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CX486M7
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2 & 3
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1 & 2
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2 & 3
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2 & 3
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2 & 3
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Open
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80486DX/DX2
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4 & 5
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2 & 3
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1 & 2
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Open
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Open
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Open
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P23S
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4 & 5
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2 & 3
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1 & 2
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Open
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Open
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Open
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P24D
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4 & 5
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2 & 3
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1 & 2
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Open
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1 & 2
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Closed
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P24S
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4 & 5
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2 & 3
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1 & 2
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Open
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Open
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Open
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P24T
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1 & 2
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1 & 2
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1 & 2
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1 & 2
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1 & 2
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Open
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Note: Pins designated should be in the closed position.
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CPU SPEED CONFIGURATION
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Speed
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JP5
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JP6
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JP7
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25MHz
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Open
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Closed
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Open
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33MHz
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Closed
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Closed
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Closed
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40MHz
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Open
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Closed
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Closed
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50iMHz
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Open
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Closed
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Open
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50MHz
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Closed
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Open
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Open
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66iMHz
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Closed
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Closed
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Closed
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CPU CLOCK DELAY CONFIGURATION
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Delay
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JP20
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0 delay
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pins 1 & 2 closed
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1 gate buffer delay
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pins 2 & 3 closed
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CPU INPUT FREQUENCY CONFIGURATION
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input
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JP23
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Single input
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pins 1 & 2 closed
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Double input
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pins 2 & 3 closed
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VESA WAIT STATE CONFIGURATION
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Wait states
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JP28
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0 wait states
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pins 1 & 2 closed
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1 wait state
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pins 2 & 3 closed
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BUS SPEED CONFIGURATION
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CPU speed
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JP29
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<= 33MHz
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pins 1 & 2 closed
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> 33MHz
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pins 2 & 3 closed
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