Spectravideo "Compumate" add-on

The picture shows the Spectravideo "Compumate"

With the release of the early home-computers, like the Commodore 64 or the Atari 800, people wanted more than just playing games; they wanted to write their own software and benefit from the increased capabilities of those new machines.
Several manufacturers, including Atari with their "Graduate", announced computer add-ons for the Atari 2600. Most of those announcements failed their promises.
Spectravideo was the manufacturer who managed to release and sell their add-on called "Compumate", though in limited quantities.
The "Compumate" was a simple case that fitted exactly onto the top of the Atari 2600 (6 switch and 4 switch versions only). It had no built-in video or sound device. It used the existing 2600 hardware to generate graphics and sound. A wired cartridge had to be inserted into the console and two cables had to be plugged into the joystick ports of the Atari 2600.
The CompuMate offered 16K of built-in ROM, 2K built-in RAM, built-in Microsoft BASIC and a 42-key sensor touch keyboard. The "Compumate" had two headphone jacks to store and load programs onto any ordinary cassette recorder. No other peripherals were available for that machine.
The "Compumate" had two built-in programs: a music-writing software, featuring two octaves / two channel music and a drawing program that allowed creating simple pictures with up to 10 different colors.

"Compumate" mounted on top of the Atari 2600

The "Compumate" retailed for about $100 in the US and for about DEM 200 (approximately EURO 102) in Germany.
Distributor for Germany was "Quelle", the world's largest home-order company. "Quelle" sold the "Compumate" under its own brand "Universum", and didn't change anything else but sticking other labels onto the "Compumate".