1980s Vintage Computers

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Connectors and leads

Several vintage computers have custom connectors for video and cassette recorders and so selecting the right lead can be tricky. This guide covers some of the computers and devices I have used.

Cassette connector

Most computers supported ordinary mono cassette recorders. This section does not cover computers that used special cassette decks such as the Commodore PET or the Atari 600XL.

All connectors shown are sockets viewed from outside the device.

Tandy TRS-80  Model 1
Tandy TRS-80 Color Computer 2
Dragon 32

The Tandy TRS-80 model 1 was one of the earliest home computers with a cassette connector, and so the pin-out was copied by many others.

5-pin DIN socket:

1 & 3 - remote
2 - ground
4 - phones (input to computer)
5 - mic (output from computer)

NEC PC-8001

7-pin DIN socket:

2 - ground
4 - mic (output from computer)
5 - phones (input to computer)
6 & 7 - remote

Acorn BBC micro and Master

7-pin DIN socket:




1 - mic (output from computer)
2 - ground
3 - phones (input to computer)
6 & 7 - remote

Research Machines Link 480Z

7-pin DIN socket:




1 - mic (output from computer)
4 - ground
6 - phones (input to computer)
3 - +5V (for relay driver)
2 - recorder 1 control (TTL output)
7 - recorder 2 control

The 480Z can switch betwen two cassette players under software control.

Cassette leads

Home cassette recorders have a 3.5mm socket for output to headphones or earpiece, and a 3.5mm socket for a microphone. Several also had a 2.5mm socket for remote control (ie only play when a short circuit is made).

Video Connector

There are two main types of video connectors, those provide a composite video output (where the video signal is mixed with sync signals) and those that provide separate video and sync outputs. Monochrome video always uses a composite output connector, whilst colour can use either.

Video output signals from a computer have to be at the right voltage and frequency for a particular monitor input, or in some cases a computer with a higher voltage output the signal can be attentuated with resistors. Video convertors or adapters are also available (eg RGB to HDMI) but these are beyond the scope of this page, I will only describe passive leads that work with monitors I have access to,

Tandy TRS-80 Model 1

This provides monochrome video only.

5-pin DIN socket:

Dragon 32

This provides compoisite video (PAL colour) and sound output on the same 5-pin DIN socket:

2 - ground
3 - composite video
1 - sound out

NEC PC-8001

This has two video outputs for monochrome or colour.

Monochrome - 5-pin DIN socket:

3 - composite video
2 - ground
1 - +12V
5 - lightpen input

Colour - 8-pin DIN socket (270°):

2 - ground
4 - HSYNC (inverted)
5 - VSYNC (inverted)
6 - red
7 - green
8 - blue
1 - +12V
3 - colour clock

Acorn BBC micro and Master

6-pin DIN socket:

1 - red
2 - green
3 - blue
4 - sync (composite H+V)
5 - ground
6 - +5V

Signal levels are TTL with positive sync by default (negative sync can be set with link S31). Frequencies are 50Hz vertical (frame) and 15.625kHz horizontal (line).

Tatung Einstein TC-01

This computer has internal jumpers to configure the video output to either RGB or YUV colour mode. The YUV setting can also be used for a monochrome output.

6-pin DIN socket:

RGB mode (nb same as Acorn computers above):

1 - red
2 - green
3 - blue
4 - sync (composite H+V)
5 - ground

YUV mode:

1 - V
2 - Y + sync
3 - U
5 - ground

For a monochrome monitor use pins 2 (composite video) and 5 only.

Atari 800XL

Following is for the UK PAL model. Provides either composite colour video, or Y+C video (combined on S-video input on a monitor or TV). Socket also provides a sound output.

5-pin DIN socket:

2 - ground
4 - composite video
3 - sound out
1 - Y + sync video
5 - C video

Commodore C64 and C128

1 - Y + sync video
2 - ground
3 - sound out
4 - composite PAL video
5 - sound in
6 - C video
8 - +5V

For a monochrome monitor use pins 1 (composite video) and 2 only.

Research Machines Link 480Z

This has two video outputs for monochrome or colour.

Monochrome - 6-pin DIN socket:

1 - composite video
2 - ground
5 - sound out
3 - VSYNC (Frame)
4 - HSYNC (Line)
6 - video (when using VSYNC and HSYNC)

The manual refers to pin 6 as 'wireframe video', exact signal levels to be confirmed.

Colour - 8-pin DIN socket (270°):

1 - sound out
2 - composite sync (inverted)
3 - red
4 - ground
5 - blue
6 - green
7 - HSYNC, Line (inverted)
8 - VSYNC, Frame (inverted)

Levels are TTL. Exact format to be confirmed.