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 cartridges. 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 as well as the hidden cost of add-ons required to overcome the limitations of the base unit.
Internally, Mattel programmers adopted Bob Del Principe's mock slogan, "Aquarius – a system for the seventies"; this was a slight, as the Aquarius was developed and released in the 1980s. 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 tiles and sub-tiles, as well as block graphics characters, so games could at least feign sprites and use semigraphics. It proved to be not enough. As COMPUTE! 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 implementations, and emulators.
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: semigraphics ( text characters - with a 25th "zero" row at top - with a size of pixels, equivalent to 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, manual, and sample software cassette Thermal printer Serial printer 1983 Mattel/Radofin Included printer cable, manual, and roll of thermal paper Color printer Serial plotter 1984 Mattel/Radofin Included printer cable, roll of paper, manual, 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, manual, and software on cassette 4kB RAM RAM cartridge 1983 Mattel/Radofin Expanded available RAM to about 6k 16kb RAM RAM cartridge 1983 Mattel/Radofin Expanded available RAM to about 18k 32kb RAM RAM cartridge 1983 Mattel/Radofin Expanded available RAM to about 34kB Quick Disk Disk-based storage 1984? Mattel/Radofin? Released only as a prototype unit 32kB RAM RAM cartridge 2015 Jay Snellen, III Expanded available RAM to about 34kB Micro Expander System expander 2016 Bruce Abbot Included 32kB RAM, custom ROM with USB BASIC, USB interface, AY-3-8910 PSG, and a 3.5mm audio jack Aquarius MX System expander 2022 Harrington, Mack, Kaylor, et al. Included 32kB 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 is 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: Aquariusprinter port ⎯⎯⎯⎯ compatible cable ⎯⎯⎯▶ Serial printer'sconnector 3.5mm TRS Function DB-25 DB-9 RS DIN Tip Data output [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 In September 2024, all remaining—hitherto missing—Aquarius characters were added to Unicode 16.0, in the Symbols for Legacy Computing Supplement Unicode block. The following table shows the Mattel Aquarius character set. Each character is shown with its Unicode equivalent.
Software There were pieces of commercial software published for the Aquarius during its commercial life (1983–84):