The Chroma 81 interface is a multi-purpose peripheral for the ZX81. Its primary function is to allow the ZX81 to be connected to a TV via a SCART socket to produce an RGB picture that is sharp and bright.

The Chroma 81 interface plugs into the expansion port of the ZX81 and connects to the TV using a standard SCART cable. There is no need to make modifications to the ZX81 since the Chroma 81 interface only requires access to those signals available on the expansion bus.

An exciting additional feature of the Chroma 81 interface is its ability to add colour to the ZX81 display. Two colour modes are provided, each supporting up to 15 colours. One mode provides an attributes file similar in concept to that found on the Spectrum. Use of this attributes file requires dedicated software to control it. The other mode provides a colour look up table that maps specific colours for each of the 128 different characters (64 normal and 64 inverse) that the ZX81 can display. This mode allows existing games to be colourised!

The Chroma 81 interface also provides the following facilities:

The Chroma 81 interface measures 10cm by 10cm. The key items of the interface are shown labelled in the following photograph:

Chroma 81 Interface

A plastic case is available for the Chroma 81 interface, as shown in the following photograph:

Chroma 81 Interface Case

The Chroma 81 interface was released on 20th October 2014, with the case released on 17th June 2018.