TANDY/RADIO SHACK

2500 SX/20

Processor

80386SX

Processor Speed

20MHz

Chip Set

Unidentified

Video Chip Set

Unidentified

Maximum Onboard Memory

5MB

Maximum Video Memory

Unidentified

Cache

None

BIOS

Unidentified

Dimensions

254mm x 218mm

I/O Options

Floppy drive interface, IDE interface, serial port, parallel port, PS/2 mouse port, riser slot

NPU Options

80387SX

CONNECTIONS

Purpose

Location

Purpose

Location

Floppy drive interface

CN1

IDE interface LED

J1

IDE interface

CN2

Riser slot

SL1

The location of the serial port, parallel port and PS/2 mouse port is unidentified.

USER CONFIGURABLE SETTINGS

Function

Label

Position

»

Audio input source select microphone

JP1

Pins 1 & 2 closed

 

Audio input source select line level

JP1

Pins 2 & 3 closed

»

Audio output source select headphone

JP2

Pins 1 & 2 closed

 

Audio output source select line level

JP2

Pins 2 & 3 closed

»

Monitor type select VGA analog or standard multiple frequency

JP3

Pins 1 & 2 closed

 

Monitor type select non standard multiple frequency

JP3

Pins 2 & 3 closed

»

VGA BIOS select PS/2 mode

JP4

Pins 2 & 3 closed

 

VGA BIOS select AT mode

JP4

Pins 1 & 2 closed

»

Video IRQ9 disabled

JP5

Open

 

Video IRQ9 enabled

JP5

Pins 1 & 2 closed

»

On board video enabled

JP6

Pins 1 & 2 closed

 

On board video disabled

JP6

Pins 2 & 3 closed

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

1.5MB

1MB

(2) 256K x 9

None

2MB

1MB

(2) 256K x 9

(2) 256K x 9

3MB

1MB

(2) 1M x 9

None

5MB

1MB

(2) 1M x 9

(2) 1M x 9

Note: Bank 0 is factory installed and is not configurable. The location is unidentified.