Currah was a British

computer A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...

peripheral A peripheral device, or simply peripheral, is an auxiliary hardware device that a computer uses to transfer information externally. A peripheral is a hardware component that is accessible to and controlled by a computer but is not a core compo ...

manufacturer, famous mainly for the

speech synthesis Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware products. A text-to-speech (TTS) system converts normal langua ...

ROM cartridge A ROM cartridge, usually referred to in context simply as a cartridge, cart, cassette, or card, is a replaceable part designed to be connected to a consumer electronics device such as a home computer, video game console or, to a lesser extent, ...

s it designed for the

ZX Spectrum The ZX Spectrum () is an 8-bit computing, 8-bit home computer developed and marketed by Sinclair Research. One of the most influential computers ever made and one of the all-time bestselling British computers, over five million units were sold. ...

Commodore 64 The Commodore 64, also known as the C64, is an 8-bit computing, 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in ...

, and other 8-bit

home computer Home computers were a class of microcomputers that entered the market in 1977 and became 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 s ...

s of the 1980s.

Currah μSource for the ZX Spectrum

The Currah μSource, commonly referred to as the ''Microsource'', from Quadhouse is a self-contained ROM cartridge with a full-function-two-pass macro assembler, Forth and a

debugger A debugger is a computer program used to test and debug other programs (the "target" programs). Common features of debuggers include the ability to run or halt the target program using breakpoints, step through code line by line, and display ...

, all of which can interact with

BASIC Basic or BASIC may refer to: Science and technology * BASIC, a computer programming language * Basic (chemistry), having the properties of a base * Basic access authentication, in HTTP Entertainment * Basic (film), ''Basic'' (film), a 2003 film ...

. It is also compatible with Interface 1.

Currah μSpeech for the ZX Spectrum

The Currah μSpeech, commonly referred to as the ''Microspeech'', plugged into the expansion port on the back of the ZX Spectrum. Additional leads were provided to feed the sound and

UHF Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...

signal from the computer into the unit. The TV aerial lead plugged into the unit and speech sounds were added into the UHF signal generated by computer. By default, the unit "spoke" every key-press the user made, even the direction keys which came out as "CURSOR". This could be controlled by a reserved variable KEYS. Typing LET KEYS=0 would turn this feature off.

Programming speech

Specific words and phrases could be spoken by assigning a value to the reserved string variable S$. This was interpreted letter-by-letter unless brackets were used to denote other

allophone In phonology, an allophone (; from the Greek , , 'other' and , , 'voice, sound') is one of multiple possible spoken soundsor '' phones''used to pronounce a single phoneme in a particular language. For example, in English, the voiceless plos ...

s. A simple example would be "(dth)is", (dth) representing the

voiced dental fricative The voiced dental fricative is a consonant sound used in some spoken languages. It is familiar to English-speakers as the ''th'' sound in ''father''. Its symbol in the International Phonetic Alphabet is eth, or and was taken from the Old Engl ...

/ð/. Sixty-three allophones were provided. Rudimentary pitch modulation could be achieved by altering the case of the letters—upper case letters being pronounced at a slightly higher pitch. A more complex example: 5 REM OKAY WISEGUY THIS IS IT 10 LET a$=" (oo)K (AA)" 20 LET b$="w(ii)z (ggg) (ii)," 30 LET c$=" (dth)is iz it" 40 LET S$=a$+b$+c$

Technical details

The unit contained a ULA which worked on a WRITE command from the microprocessor, a

ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...

containing the keyword speech patterns, and an SP0256-AL2 speech processor. It also contained a clock for clear speech and an audio modulator to transfer the sound to the TV lead. A small adjustment screw was provided, to allow fine tuning of the audio output. The unit allocated itself the top 256 bytes of memory at switch-on and moved down the USR graphics and RAMTOP. This made it incompatible with some programs, particularly games, which use that space for machine code. For cost reasons, the unit did not provide for daisy-chaining of further devices on the computer's expansion port. Many

joystick A joystick, sometimes called a flight stick, 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. Also known as the control column, it is the principal control devic ...

interface manufacturers took the same approach, meaning that you could not have a joystick and the MicroSpeech unit plugged in at the same time. ''Booty'' ( Firebird Software Ltd) detected the presence of a MicroSpeech unit and presented the user with a completely different game to that which would be played if the MicroSpeech unit was not present.

History

Currah was acquired by

DK'Tronics DK'Tronics Ltd (stylised as dk'tronics) was a British software and hardware company active during the 1980s. It primarily made peripherals for the ZX Spectrum and Amstrad CPC but also released video games for the ZX81, ZX Spectrum, Commodore 64, ...

in 1985. DK'Tronics continued to manufacture the MicroSpeech unit, and many of their software titles (such as ''

Maziacs ''Maziacs'' is an action adventure maze game published by DK'Tronics in 1983 for the ZX Spectrum, Commodore 64, and MSX. History ''Maziacs'', written by Don Priestley, was based on his earlier ZX81 game '' Mazogs''

'' and '' Zig Zag'') supported it.

External links

Review of the product
at '' CRASH'' magazine
List of Currah products at World of Spectrum
'' community website

References

{{Sinclair computers and clones Defunct computer companies of the United Kingdom Defunct computer hardware companies Home computer hardware companies Speech synthesis ZX Spectrum