# Mattel Aquarius

The Aquarius is a home computer designed by Radofin and released by Mattel Electronics in 1983. Based on the Zilog Z80 microprocessor, the system has a rubber chiclet keyboard, 4 KB of RAM, and a subset of Microsoft BASIC in ROM. It connects to a television set for audiovisual output, and uses a cassette tape recorder for secondary data storage. A limited number of peripherals, such as a 40-column thermal printer, a 4-color printer/plotter, and a 300 baud modem, were released. The Aquarius was discontinued in October 1983, only a few months after it was launched.

## Development

Looking to compete in the home computer market, Mattel Electronics turned to Radofin, the Hong Kong based manufacturer of their Intellivision consoles. Radofin had designed two computer systems. Internally they were known as "Checkers" and the more sophisticated "Chess". Mattel contracted for these to become the Aquarius and Aquarius II, respectively.
Aquarius was announced in 1982 and finally released in June 1983, at a price of $160. Production ceased four months later because of poor sales. Mattel paid Radofin to take back the marketing rights. Four other companies: CEZAR Industries, CRIMAC, New Era Incentives, and Bentley Industries also marketed the unit and accessories.
The Aquarius was often bundled with the Mini-Expander peripheral, which added game pads, an additional cartridge port for memory expansion, and the General Instrument AY-3-8910 sound chip. Other peripherals were the Data recorder, 40 column thermal printer, 4 and 16 KB RAM carts. Less common first party peripherals include a 300 baud cartridge modem, 32 KB RAM cart, four color plotter, and Quick Disk drive.

## Reception

Although less expensive than the TI-99/4A and VIC-20 home computers it competed against, the Aquarius was made a less attractive purchase by its comparatively weak graphics and limited memory. Internally, Mattel programmers adopted Bob Del Principe's mock slogan, "Aquarius – a system for the seventies", which was a sleight because the Aquarius was developed and released in the eighties. Of the 32 software titles Mattel announced for the unit, only 21 were actually released, and most of those were ports of Intellivision games, often inferior ports. Because of the hardware limitations of the Aquarius, the quality of many games suffered. The absence of any all-points-addressable graphics mode was so glaring that Radofin crafted the character set for the Aquarius with many tile and sub-tile, as well as block graphics characters, so games could at least feign sprites and use semigraphics. It proved not enough. As one then-popular magazine put it:
"The Aquarius suffered one of the shortest lifespans of any computer—it was discontinued by Mattel almost as soon as it hit store shelves, a victim of the 1983 home computer price wars."
Decades after the spectacular market failure and exceptionally short original product life of the Aquarius, retrocomputing enthusiasts returned to this platform with renewed interest and intrigue, partly due to rarity and hacker interest in working within—and pushing—tight system constraints. Multiple homebrew games were thus published scores of years after-the-fact, and development and niche user interest in Aquarius software continues, using surviving original hardware, FPGA reimplementations, and emulators. In September 2024, all remaining—hitherto missing—Aquarius characters were added to Unicode 16.0, in the Symbols for Legacy Computing Supplement Unicode block.

### Aquarius II

Just after the release of the Aquarius, Mattel had announced plans for the Aquarius II, and there is evidence that the Aquarius II reached the market in small numbers under the Radofin brand, but it was also not a commercial success. Technically otherwise identical to the previous version, the Aquarius II came with a 16 KB RAM extension, mechanical keyboard and Extended Basic.

## Technical specifications

* CPU: Zilog Z80 @ 3.5 MHz
* Memory: 4 KB RAM, expandable to 36 KB; 8 KB ROM
* Keyboard: 48-key rubber chiclet keyboard
* Display: 80 × 72 semigraphics (40 × 24 text characters - with a 25th "zero" row at top - with a size of 8 × 8 pixels, equivalent to 320 × 192 pixels) in 16 colors (TEA1002 colour encoder)
* Sound: one voice, expandable to four voices
* Ports: television, cartridge/expansion, tape recorder, printer
* PSU: non-removable external power supply hard-wired into case providing 8.8 / 16 / -19 VDC

## Peripherals

Despite its relatively short time on the market, Mattel Electronics and Radofin managed to have most of the announced peripherals available within a month or so of the release of the system. Some products never materialized beyond prototype phase, and some were available only in specific markets. Beginning in 2016, new user-designed peripherals began to show up, mostly on eBay or on vintage computer forums such as AtariAge.
| Name | Product Type | Year | Creator | Notes |
| Mini Expander | System expander | 1983 | Mattel/Radofin | Included two Hand Controllers, with slots for RAM and ROM cartridges. Difficult to find outside of North America |
| Data Recorder | Serial storage device | 1983 | Mattel/Radofin | Included data cable and sample software cassette |
| Thermal Printer | Serial printer | 1983 | Mattel/Radofin | Included printer cable and roll of thermal paper |
| Color Printer | Serial plotter | 1984 | Mattel/Radofin | Included printer cable, roll of paper, and spare pens. Unit was a rebrand of a similar Tandy/RS printer |
| Modem | Cartridge-based 300 Baud Modem | 1984 | Mattel/Radofin | Included phone cables and software on cassette |
| 4k RAM | RAM cartridge | 1983 | Mattel/Radofin | Expanded available RAM to about 6k |
| Quick Disk | Disk-based storage | 1984? | Mattel/Radofin? | Released only as a prototype unit |
| 32k RAM | RAM cartridge | 2015 | Jay Snellen, III | Expanded available RAM to about 34k |
| Micro Expander | System Expander | 2016 | Bruce Abbot | Included 32k RAM, custom ROM with USB BASIC, USB interface, AY-3-8910 PSG, and 3.5mm audio out |
| Aquarius MX | System Expander | 2022 | Harrington, Mack, Kaylor, et al. | Included 32k RAM, custom ROM with MX BASIC 2.0, USB interface, AY-3-8910 PSG, and DB9 hand controller ports |

## Interfacing

The Aquarius manual did not contain detailed documentation on any of the ports available, but Aquarius FAQ files, and later retrocomputing websites shared the ascertained information.

### Cassette port

The cassette port, although using the same 5-Pin DIN 41524 connector as the TRS-80, did not have the same pinout and thus was incompatible with readily available cables for the TRS-80, even though they physically fit the sockets on both the computer and cassette player. The Aquarius-branded cassette deck came with the appropriate cable.
The cassette port a 5-pin female DIN 41524 connector
| Pin | Function Aquarius | Function TRS-80 |
| 1 | MIC | REMote |
| 2 | Common Ground | Common Ground |
| 3 | EAR | REMote |
| 4 | Not used | EAR |
| 5 | Not used | MIC |
The MIC and EAR connections from the Aquarius each go to the tip/center of one of the two mini-plugs being attached to the recorder; Ground goes to the base/outside of both mini-plugs.

### Printer port

The printer interface is a 3.5 mm mini-stereo socket with 3 lines (tip, ring, sleeve), the same as on the Mattel Entertainment Computer System. The Aquarius printers came with their own cables. The interface conforms to RS-232 serial signal standards (+12VDC/-12VDC), and with knowledge of its pinout it is possible to interface with RS232-compatible serial printers.
Typical serial printers had DB-25 interfaces; some had DE-9 interfaces; and some Radio Shack (RS) printers had round 4-pin female DIN serial interfaces (with the pin sockets numbered left-to-right: 4, 3, 2, 1).
The following shows the pinout for the printer connector on the Aquarius, as well as for connection with the aforementioned serial printers:
| Aquarius printer port | ⎯⎯⎯⎯ compatible cable ⎯⎯⎯▶ | Serial printer's connector | Serial printer's connector | Serial printer's connector |
| 3.5mm TRS | Function | DB-25 | DB-9 | RS DIN |
| Tip | Data Out [to printer] (TxD) | Pin 3 | Pin 2 | Pin 4 |
| Ring | Printer Busy/Data Set Ready (DSR) | Pin 20 | Pin 4 | Pin 2 |
| Sleeve | Signal Ground (GND) | Pin 7 | Pin 5 | Pin 3 |
The serial transfer protocol is fixed to 1200 baud 8N2, and provided both carriage return and line feed commands to the printer; thus the printer needed to be set to not also execute a line feed on carriage return. Because the Aquarius printer port used only a minimum number of pins (TxD/DSR/GND), the use of this port was unidirectional, from the computer to the printer (or other attached serial device).

## Character set

The following table shows the Mattel Aquarius character set. Each character is shown with its Unicode equivalent.
Mattel Aquarius :
| | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F |
| 0x | £ | ½ | ¼ | ¾ | ÷ | © | → | ← | ↑ | ↓ | ↗ | ↙ | ↘ | ↖ | 𜷰 | 𜷱 |
| 1x | 𜷲 | 𜷳 | 𜷴 | 𜷦 | 𜷧 | 𜷨 | 𜷩 | 𜷪 | 𜷫 | 𜷵 | ▗ | ▝ | ▖ | ▘ | ▚ | ▄ |
| 2x | SP | ! | " | # | $ | % | & | ' | ( | ) | * | + | , | - | . | / |
| 3x | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | : | ; | < | = | > | ? |
| 4x | @ | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O |
| 5x | P | Q | R | S | T | U | V | W | X | Y | Z | [ | \ | ] | ^ | _ |
| 6x | ` | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o |
| 7x | p | q | r | s | t | u | v | w | x | y | z | { | | | } | ~ | █ |
| 8x | ▇ | ▏ | 𜷬 | 𜷭 | 🮏 | 🮌 | ▒ | ● | ▂ | ▆ | 🛧 | 𜷸 | 𜷮 | 𜷯 | ▶ | ▲ |
| 9x | ▁ | ▉ | 𜷶 | 𜷷 | 🮎 | 🮍 | ⬤ | ▎ | ▍ | ▌ | 𜷹 | ✈ | 𜷺 | 𜷻 | ◀ | ▼ |
| Ax | NBSP | | | | | | | | | | | | | | | |
| Bx | | | | | | | | | | | | | | | | |
| Cx | ◢ | ◣ | 🯨 | ▊ | ▪ | ♦ | · | 🯬 | ┼ | 🯪 | ╱ | 🯭 | ┴ | ├ | ┐ | └ |
| Dx | 𜷿 | 𜷾 | 🯪 | 𜷽 | ♥ | ♣ | │ | 🯮 | ╳ | 🯯 | ╲ | 🯫 | ┬ | ┤ | ┌ | ┘ |
| Ex | | | | | | | | | | | | | | | | |
| Fx | | | | | | | | | | | | | | | | █ |

## Software

Software published for the Aquarius during its commercial life (1983–84):
| Commercial software | Publisher | Release date |
| Advanced Dungeons & Dragons: Treasure of Tarmin † | Mattel Electronics | 1983 |
| Aliens | Add On Electronics | 1983 |
| Aquapack 1 (Snake, Breakout, Moon Shuttle) | Apocalypse Software | ???? |
| Astrosmash † | Mattel Electronics, Radofin Electronics | 1983 |
| Battle Zone | Add On Electronics | 1984 |
| Biorhythms † | Mattel Electronics | 1983 |
| Bounder | Add On Electronics | 1984 |
| Breakout | Add On Electronics | 1984 |
| Burger Time † | Mattel Electronics, Radofin Electronics | 1983 |
| Chess (Dick Smith Electronics) | Dick Smith Electronics | 1983 |
| Chess (Mattel)† | Mattel Electronics | 1983 |
| Chuckman | Add On Electronics | 1983 |
| D-Fenders | Add On Electronics | 1983 |
| Deathrace | Apocalypse Software | ???? |
| Demo Cassette (Stalactites, Macho-Man, Torment, Cute Cubes, Alien Quest, Mad Mould) | Radofin Electronics | 1983 |
| Diamond Mine | Add On Electronics | 1984 |
| Disco Fever | Add On Electronics | 1984 |
| Ed-On | Add On Electronics | 1983 |
| Extended Microsoft Basic (Mattel)† | Mattel Electronics | 1983 |
| FileForm † | Mattel Electronics | 1983 |
| FinForm † | Mattel Electronics. Radofin Electronics | 1983 |
| First Adventure | Digital Output | 1984 |
| Games Pack 1 (Stalactites, Macho-Man, Othello, Mutants) | Add On Electronics | 1983 |
| Games Pack 2 (Bounder, Local Bomber, Breakout, Night Driver) | Custom Cables International | 1984 |
| Games Pack 3 (Metior, Sheepdog, Mastermind, Depthcharge) | Custom Cables International | 1984 |
| Games Pack 4 (Painter, Pontoon, Grand Prix, Alien Storm) | Custom Cables International | 1984 |
| GamesTape (Dodge It, Trojan Dragon, Death Trap, Tablets of Hippocrates) | Fawkes Computing | 1984 |
| Gamespack 1 (Snake, Masterguess, Symon, Bomber, Hi-Lo) | Processor Software | 1984 |
| Gamespack 2 (Collector, Blocked!, Rocket Run, Minefield, Air-Defence) | Processor Software | 1984 |
| Ghost Hunter | Dick Smith Electronics | ???? |
| Grid Bug | Add On Electronics | 1983 |
| Hopper | Microdeal | 1984 |
| Invaders | Dick Smith Electronics | 1984 |
| Kronos Europea Cassette (Gamble, Gunfight, Mad Mould, Outline) | Radofin Electronics | 1984 |
| Logo † | Mattel Electronics | 1983 |
| Maths Armada | Dick Smith Electronics | 1984 |
| Mazantics | Add On Electronics | 1983 |
| Melody Chase † | Mattel Electronics | 1983 |
| Millypede | Add On Electronics | 1983 |
| Mower Man | Add On Electronics | 1984 |
| N-Vaders | Add On Electronics | 1983 |
| Night Stalker † | Mattel Electronics, Radofin Electronics | 1983 |
| Outpack 1 (Snake, Masterguess, Symon, Bomber, Hi-Lo) | Digital Output | 1984 |
| Outpack 2 (Collector, Blocked, Rocket Run, Minefield, Air-Defence) | Digital Output | 1984 |
| Outpack 3 (Gunfight, Gambler, Moonlander, Tracker, Nim) | Digital Output | 1984 |
| Outpack 4 (Super Slot, Golf, Invasion, Killer Sub, Survival) | Digital Output | 1984 |
| Outpack 5 (Timetrap, Gro-Worm, Wampus Gold, Bumpers, Space Shoot) | Digital Output | 1984 |
| Pac Mr | Add On Electronics | 1983 |
| Pack 1 (Bombardier, Fruit Machine, Hang Man, Alien Descent, Escape) | Mercury House | ???? |
| Pack 2 (Dungeon Adventure, U-Boat, Golf, Star Catcher, Moonraker) | Mercury House | ???? |
| Phrogger | Add On Electronics | 1984 |
| Postman Pot | Add On Electronics | 1984 |
| Rally Driver | Micro Mart Software | 1984 |
| Read It | Dick Smith Electronics | 1984 |
| Scramble | Micro Mart Software | 1984 |
| Snafu † | Mattel Electronics, Radofin Electronics | 1983 |
| Space Ram | Dick Smith Electronics | 1984 |
| Space Speller † | Mattel Electronics | 1983 |
| Tracker | Digital Output | ???? |
| Tron: Deadly Discs † | Mattel Electronics, Radofin Electronics | 1983 |
| Utopia † | Mattel Electronics, Radofin Electronics | 1983 |
| Zero In † | Mattel Electronics | 1983 |
| Zorgon's Kingdom | Romik Software | 1984 |
    † ROM Cartridge
Homebrew software developed for the Aquarius:
| Homebrew games | Publisher/Developer | Release date |
| AlphaMix | Oasis | |
| Aquariworm | Cronosoft / Roy Templeman | 2020 |
| Bomb Catcher II | Cronosoft / Roy Templeman | 2021 |
| Astro Covoy | Cronosoft / Roy Templeman | 2024 |
| Crossword Computer | Oasis | |
| Doomsday Defender | Cronosoft / Roy Templeman | 2022 |
| Electric Organ | Oasis | |
| Fall of the Eastern Blocks | Leinen, Jason J. | 1999 |
| Flying | Oasis | |
| Football | D.A. Spencer | |
| Fruit Machine | D.A. Spencer | |
| Gunnery | Oasis | |
| Mastercode | Oasis | |
| Pontoon | D.A. Spencer | |
| Rollerball | D.A. Spencer | |
| Sketch | Oasis | |
| Ski | D.A. Spencer | |
| Solitaire | Oasis | |
| Space Collision | D.A. Spencer | |
| Spacepits | D.A. Spencer | |
| Strikeforce | D.A. Spencer | |
| Symmetry | Oasis | |
| Turmoil 2022 | 8-Bit Milli Games | 2022 |
| Warp Factor | Cronosoft / Roy Templeman | 2023 |
| Grid Trap | Cronosoft / Roy Templeman | 2024 |
| Paqu Deluxe | Cronosoft / Roy Templeman | 2024 |
| 10 Liner - Invader | Roy Templeman | 2019 |
| 10 Liner - Cave Navigator | Roy Templeman | 2021 |
| 10 Liner - Attack of the ROM Robots | Roy Templeman | 2022 |
| 10 Liner - AstroRun | Roy Templeman | 2023 |
| 10 Liner - Paqu | Roy Templeman | 2024 |