UNIDENTIFIED

XTT

Processor

8088

Processor Speed

4.77/8MHz

Chip Set

Unidentified

Video Chip Set

None

Maximum Onboard Memory

640KB

Maximum Video Memory

None

Cache

None

BIOS

Unidentified

Dimensions

330mm x 218mm

I/O Options

None

NPU Options

8087

CONNECTIONS

Purpose

Location

Purpose

Location

Power LED & keylock

JP7

Turbo switch

JP8 pins 3 & 4

Reset switch

JP8 pins 1 & 2

Speaker

JP9

USER CONFIGURABLE SETTINGS

Function

Label

Position

 

Wait state select 3 wait states

JP3

Pins 2 & 3 closed

 

Wait state select 2 wait states

JP3

Pins 1 & 2 closed

 

SW1/5 is set to on

JP5

Closed

 

SW1/5 is set to off

JP5

Open

»

Factory configured - do not alter

SW1/1

Off

 

NPU not installed

SW1/2

On

 

NPU installed

SW1/2

Off

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

Bank 3

256KB

(9) 41256

None

None

None

512KB

(9) 41256

(9) 41256

None

None

640KB

(9) 41256

(9) 41256

(9) 41256

None

640KB

(9) 41256

(9) 41256

(9) 4164

(9) 4164

DRAM JUMPER CONFIGURATION

Number of banks with 41256 chips installed

JP4

0

Pins 1 & 3, 2 & 4 closed

1

Pins 2 & 4 closed

2

Pins 1 & 3 closed

3

Open

DRAM SWITCH CONFIGURATION

Banks used

SW1/3

SW1/4

1

On

On

2

On

Off

3

Off

On

4

Off

Off

CPU SPEED SELECTION

Speed

JP6

Switchable through keyboard

Pins 1 & 2 closed

4.77MHz

Open

8MHz

Pins 2 & 3 closed

FLOPPY DRIVE SELECTION

Drives installed

SW1/7

SW1/8

1

On

On

2

On

Off

3

Off

On

4

Off

Off

MONITOR SELECTION

Type

SW1/5

SW1/6

EGA

On

On

Color (80 x 25)

On

Off

Color (40 x 25)

Off

On

Monochrome

Off

Off

BIOS SELECTION

Type

JP2

2764

Pins 3 & 15, 4 & 14, 5 & 13, 6 & 12, 7 & 11, 8 & 10 closed

27128

Pins 2 & 15, 3 & 14, 4 & 13, 5 & 12, 6 & 11, 7 & 10 closed

27256

Pins 1 & 15, 2 & 14, 3 & 13, 4 & 12, 5 & 11, 6 & 10 closed