ZX Interface 2
Encyclopedia
Peripheral
A peripheral is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture....
from Sinclair Research
Sinclair Research Ltd
Sinclair Research Ltd is a British consumer electronics company founded by Sir Clive Sinclair in Cambridge. Originally incorporated in 1973 as Ablesdeal Ltd., it remained dormant until 1976, and did not adopt the name Sinclair Research until 1981....
for its ZX Spectrum
ZX Spectrum
The ZX Spectrum is an 8-bit personal home computer released in the United Kingdom in 1982 by Sinclair Research Ltd...
home computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...
released in September 1983. It had two joystick
Joystick
A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Joysticks, also known as 'control columns', are the principal control in the cockpit of many civilian and military aircraft, either as a center stick or...
ports and a ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
cartridge slot, which offered instant loading times. The joystick ports were not compatible with the popular Kempston interface
Kempston Micro Electronics
Kempston Micro Electronics was an electronics company specialising in computer joysticks and related home computer peripherals during the 1980s. Kempston was based in Kempston, Bedfordshire, England.- Interfaces :...
, and thus did not work with most Spectrum games released prior to the launch of the ZX Interface 2. In addition, the pass-through expansion bus provided was stripped, only allowing a ZX Printer
ZX Printer
The Sinclair ZX Printer is a spark printer which was produced by Sinclair Research for its ZX81 home computer. It was launched in 1981, with a recommended retail price of £49.95....
to be attached.
Compatible titles
Availability of cartridge software was very limited: The cost was almost twice as much as the same game on cassette tapeCompact Cassette
The Compact Cassette, often referred to as audio cassette, cassette tape, cassette, or simply tape, is a magnetic tape sound recording format. It was designed originally for dictation, but improvements in fidelity led the Compact Cassette to supplant the Stereo 8-track cartridge and reel-to-reel...
, and each cartridge could only hold 16 KiB
Kibibyte
The kibibyte is a multiple of the unit byte for quantities of digital information. The binary prefix kibi means 1024; therefore, 1 kibibyte is . The unit symbol for the kibibyte is KiB. The unit was established by the International Electrotechnical Commission in 1999 and has been accepted for use...
, making it almost immediately obsolete as the majority of Spectrums sold were 48K-models, which the software publishers targeted.
Only ten games were commercially released:
- JetpacJetpacJetpac is a ZX Spectrum, VIC-20 and BBC Micro video game developed and released by Ultimate Play The Game in 1983. The game is the first in the Jetman series, and was the company's very first release. The game was written by Chris Stamper with graphics by Tim Stamper...
- PSSSTPSSSTPssst is a ZX Spectrum video game made by Ultimate Play The Game in 1983. In the game Robbie the Robot has to protect his plant as it is attacked by various insects , each of which needs a different repellent. The game was written by Chris Stamper and Tim Stamper...
- CookieCookie (game)Cookie is a ZX Spectrum video game written by Chris and Tim Stamper and published by Ultimate Play The Game in 1983. It was one of four 16K games by Ultimate that were available on ROM format for use with the ZX Interface 2...
- Tranz AmTranz AmTranz Am is a ZX Spectrum video game released by Ultimate Play The Game in 1983. The game was one of the very few Spectrum games also available in ROM format for use with the Interface 2....
- Chess
- Backgammon
- Hungry HoraceHorace seriesThe Horace video game series was created in the 1980s by William Tang for Beam Software. The series comprised Hungry Horace, Horace Goes Skiing and Horace and the Spiders....
- Horace and the SpidersHorace seriesThe Horace video game series was created in the 1980s by William Tang for Beam Software. The series comprised Hungry Horace, Horace Goes Skiing and Horace and the Spiders....
- Planetoids
- Space Raiders
Paul Farrow has demonstrated that it is possible to produce custom ROM cartridges, including the ability to exceed the 16 KiB
Kibibyte
The kibibyte is a multiple of the unit byte for quantities of digital information. The binary prefix kibi means 1024; therefore, 1 kibibyte is . The unit symbol for the kibibyte is KiB. The unit was established by the International Electrotechnical Commission in 1999 and has been accepted for use...
design limitation of the ROM cartridges .
Joystick ports
The interface two came with two joystick ports that (unlike the KempstonKempston Interface
The Kempston Interface, produced by Kempston Micro Electronics, was the generic name for any interface on Sinclair's ZX Spectrum series of computers that allowed joysticks complying with the de facto Atari 2600 standard to be used with the machine. It was one of the most widely supported standards...
which used the IN31 command) were mapped to actual key presses. Player 1 was mapped to 1-5 and player 2 was mapped to 6-0. This initially seemed at odds with Sinclair's own keyboard layout, given that the keyboard itself had the cursor keys mapped to 5-8 with 0 typically being used by games as a fire button. Joystick interfaces that mapped to the cursor keys were available, but like the popular Kempston interface they were limited to supporting a single joystick only. It was the twin joystick feature of the ZX Interface 2 that turned out to be its major selling point.
See also
- ZX Interface 1ZX Interface 1A peripheral from Sinclair Research for its ZX Spectrum home computer, the ZX Interface 1 was launched in 1983. Originally intended as a local area network interface for use in school classrooms, it was revised before launch to also act as the controller for up to eight ZX Microdrive high-speed...
– A peripheral with ports for ZX MicrodriveZX MicrodriveThe ZX Microdrive is a magnetic tape data storage system launched in July 1983 by Sinclair Research for their ZX Spectrum home computer. The Microdrive technology was later also used in the Sinclair QL and ICL One Per Desk personal computers.-Development:...
s, RS-232RS-232In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
serial units, and ZX Net cables (for connection to a ZX Net local area network)