Sinclair Computer Hardware Factsheet ------------------------------------ Version 1.2 "Uncle" Clive Sinclair, inventor of the handheld pocket calculator, digital watch and small screen TV pioneer, founded Sinclair Research and developed the ZX80 microcomputer in March of 1979. Within a year, he had the ZX80 in the British market, selling for about 100 British pounds. In 1981, Sinclair Research developed and marketed the improved ZX81. Both computers were available in kit form, and had a dramatic effect on prices of computers that were available to home and hobbyist users. Other computer manufacturers were forced to lower prices drasticly, which put more computers in more homes in a shorter span of time. Indeed, the Sinclair line of computers, nearly forgotten by all except a dedicated remnant of hobbyists in this Pentium era, were a catalyst that accelerated the placement of computers as a common household and business item. This factsheet is intended to be a briefing of the hardware that comprised the Sinclair line of computers. It is intended to give a view at the chipset level as well as the hardware system level. It is a growing body of information as the details of this line of computers are compiled by its current devotees. Third party hardware is also included, since the third party developers of interfaces, mass storage, memory expansions, and peripherals have helped to keep the Sinclair computers a viable tool for personal and business use. Submission of facts that were omitted or are inaccurate in this version are graciously welcomed. My experience is with the T/S1000 and T/S2068, and many peripherals associated with these computers. My sources include some back issues of Sync, Update, T/S2068 Technical Manual and Syncware news. I have avoided mention of any prices of any piece of hardware. Besides the price differences of 1985, 1990 and 1995, there is the matter of denominating it in Pounds, Dollars, Kroner, Sheckels or whatever, and I prefer to stick with simpler topics, such as ULA and SCLD pinouts. More importantly, there is a large body of information about these machines residing in closets and stashed away in boxes that we need to liberate and make available to the curious and the perhaps eccentric souls of those who dare venture into the Sinclair Zone. Email submissions/corrections/rants directed to me may be sent to: Bob.Johnson@pdsig.com WANTED: Detailed descriptions of Interface 2, Spectrum+, +2, +3 LEGAL NOTE: HA! I despise most lawyers. One such vermin screwed my brother over when he was the victim of an accident. So how about this: This document is free to print out, scoff at, reside in Web pages, be ignored, get folded, spindled and mutilated, be admired, be translated, instruct, inform, and delay the onslaught of a drab world full of PeeCee clones. COMPUTERS --------- NOTE: The Sinclair line of computers used the Z80A 8-bit CPU. The ZX81 and T/S1000 used custom logic chips such as the ULA and were of such simple, low-cost design that they drove prices of competing computers way down, thus putting computers into the hands of millions of hobbyists and home users. The most important difference from all other home computers, and at the same time THE characteristic of the ZX-family is the lack of a special video controller. This task is managed by the Z80 processor together with some very clever and at the same time very short software routines (less than 300 bytes) and a little hardware. Of course this is the reason why the ZX81 (in SLOW-mode) is a little bit slower than other home computers. Other common characteristics are: * "keyboard" with 40 keys * simple cassette port with about 300 baud * bus connector with 46 (-2) connections * 3.25 MHz CPU clock frequency * 9 Volts operating voltage * TV connector for the use with a normal TV-set * the B&W screen has 32x24 UPPERCASE characters, 64x44 graphics * no ASCII code Timex was licensed by Sinclair to sell Sinclair machines in designated countries around the world. Timex and Sinclair signed an agreement that precluded each other from competing in one another's territories, which is why you would rarely see a Timex/Sinclair in England and rarely see a Spectrum in Canada or the US. Eventually, independant dealers shipped both sets of machines to both sides of the Atlantic, and elsewhere. Early Sinclair Computers: - MK14 -- Sinclair's first foray into the computer market - the (not very well known) MK14. This had a strange proprietary CPU (which may have been called the SC/MP), 256 bytes of RAM (expandable to 512), a seven segment LED display and a hex keypad. It was supplied as a kit and came with an instruction book with several simple programs such as timers, limited games, etc. - NewBrain -- Also, Sinclair designed the NewBrain, but this was sold off and developed by Grundy Electronics (? this name is probably wrong). This was a Z80-based machine with built-in gas plasma display and could also be connected to the TV. And then, the Famous ZX series: - ZX80 -- 4K Sinclair Integer BASIC ROM, 1K RAM, white plastic case, membrane keyboard, 32x24 UPPERCASE character monochrome display, with the bottom two lines used by the OS for the edit line, RF modulated video output. This machine was upgradeable with an 8K ROM kit and keyboard overlay. Also available as a kit. - ZX81 -- 8K Sinclair Floating Point BASIC ROM, 1K RAM in a small black plastic case, membrane keyboard, 32x24 UPPERCASE character monochrome display, 64x44 graphics, RF modulated video output. Also available as a kit. - T/S1000 (Timex/Sinclair) -- American version of the ZX81. It is 100% compatible. In fact, early models had a ZX81 circuit board. Two 4x1K RAM chips replaced by single 8x2K RAM. It looks the same as a ZX81 except it has a Timex/Sinclair logo where the Sinclair logo of the ZX81 appears. - T/S1500 -- 16K RAM version of the T/S1000 with a new case design. Raised rubber chiclet keys. It is also 100% compatible with the ZX81. - ZX Spectrum -- 16K Sinclair BASIC ROM, 48K RAM, 8 color, 256x192 graphics, with BRIGHT and FLASH modes for each 8x8 pixel character position, for a total of 16 colors, software BEEP tones for sound, raised rubber chiclet keys. - ZX Spectrum + -- 48K model of the Spectrum with upgraded keyboard - ZX Spectrum 128 -- 128K Spectrum, with upgraded keyboard and bank switched RAM expansion. Same keyboard as ZX Spectrum +, but with external heatsink. 32K ROM, arranged as 2x16K (one containing the original 16K BASIC ROM, and the other containing the new editor, etc). The 128 also had a MIDI/RS232 port, a built-in RGB monitor port and a socket for a numeric keypad. Sound was fed through the TV for the first time. Operation was different - the 128 had a "48K mode" where it behaved much like a ZX Spectrum +, and the new 128 modes. BASIC editing had changed with the inclusion of a full-screen editor requiring keywords to be typed out in full. The BASIC was extended providing access to the new RAM disk and soundchip. The very last ZX Spectrum 128s contained Amstrad-badged ULAs. - The ZX Spectrum +2 was the first product to be launched by Amstrad after its Sinclair takeover (boo!) Internally, it is the ZX Spectrum 128 (which was launched by Sinclair, while still owned by Sir Clive. The 128 has a ZX Spectrum + case, with '128K' label and exterior heat sink being the visible differences. There is a MIDI port too if my memory serves correctly). Externally, it looks typically Amstrad - tape deck, incompatible joystick ports, etc, in a grey box. - The ZX Spectrum +2A was launched after the +3. Internally, it is the ZX Spectrum +3 (the disk drive one). It even features the DOS, which upon bootup notifies which drives are available under the menu box. The ZX Spectrum +3DOS (and therefore the +2A) has some compatibility problems with earlier Speccy models, some old software won't work. Externally, it is exactly the same as the +2 but in black. The exterior label even reads +2 instead of +2A. The old 9V PSU as used on all Speccys was replaced in the +3 by a new one (presumably for the disk drive etc?), and the +2A takes a variant of that. - T/S2068 -- American version of the Spectrum. Has an additional 8K extension ROM, cartridge port, two joystick ports and AY-3-8912 sound chip with extra Sinclair BASIC commands to support these devices (STICK, SOUND). Packaged in a hard plastic silver case with nonstandard plastic keys. The TS2068 is Timex's re-engineered 48K Spectrum. It was released in Fall 1983 just before Timex Computer Corp folded in Spring 1984. A rogue arm of Timex in Portugal continued to sell TC2068s (same as TS2068) and TC2048s (an improved Spectrum - more on this in a sec) until 1989. They, of course, were only allowed to sell in non-Sinclair controlled marketplaces. Timex recognized that a 48K Spectrum would not continue being competitive in North America for long without changes being made. They developed two computers that were to be North America's debut of the Spectrum. One was called the TS2048 and the other the TS2068. The TS2048 was basically a 48K Spectrum w/ Kempston joystick and the advanced video modes of the TS2068 (see below). The TS2068 was a completely different computer with the Spectrum as its roots. Timex decided to only sell the TS2068. When sales over Christmas 1983 were disappointing, they pulled the plug. Timex of Portugal, no doubt encouraged by the Spectrum's popularity in Europe, continued to sell the TS2068 and offered the TS2048 as the TC2068 and TC2048 in parts of Europe, notably Portugal and Poland (got this info from two fellows from each of those countries who mentioned that the Timex computers were very popular there). When Timex pulled the plug, they dumped all their surplus TS2068s in Argentina. As for the number of TS2068s manufactured, I remember hearing a figure of 60,000 (but I'm not too sure). I have no idea about how many were sold by Timex of Portugal in Europe. Maybe someone from there will enlighten us? Here are the features of the TS2068: * Z80A processor clocked at 3.58Mhz * AY-3-8912 Sound Chip (same as 128K Spectrums) w/ clock 1.76475Mhz It is attached to different ports compared with the Spectrums, so you don't hear AY music when playing Speccy games (of course, it can be overcome). I mention the clock rate here because it is slightly different from the Spectrum's. * 72K (48K RAM; 24K ROM) which is bankswitched between three internal 64K memory banks called the HOME bank (16K ROM, 48K RAM), the EXROM bank (8K ROM; this one is not completely decoded and can only hold 8K), and the DOCK bank which is empty and is reserved for cartridges. The memory is bankswitched in 8K chunks. * The BASIC is a superset of 48K Spectrum BASIC (ie - has a few commands added). * A cartridge dock is located under a door on the right side of the computer. * Two joystick connectors (not compatible with any Sinclair joysticks) * RF out, Composite video available on jacks. RGB signals available on rear edge connector. * Hardware was nicely designed to support DMA and memory bankswitching. * Video Modes: - 256x192 pixel, 32x24 attributes (Spectrum screen) - 256x192 pixel, 32x192 attributes (extended colour mode) - Dual screen mode where you could flip between two Spectrum screens - 512x192 pixel monochrome As for Spectrum compatibilty: The tape I/O is the same so you can load Spectrum tape files. Spectrum BASIC is a subset of the TS2068's BASIC, so you can run Spectrum BASIC programs. The TS2068's ROM is different, though, so you can't run Spectrum m/c that makes use of the ROM. I have found that without the aid of a Spectrum emulator, I can run about 7% of the Spectrum's commercially available software. The Spectrum emulator is really a Spectrum ROM on cartridge (there are other forms) that is bankswitched into the lower 0-16K region. The top 48K region is filled with RAM. To the software this looks exactly the same as a 48K Spectrum. There are a few hardware reasons for incompatibilities (if you are really interested you can check out sna2jlo1.zip on nvg in /pub/sinclair/utils/ts2068 - you'll get a brief overview for reasons for incompatibilities). Using an emulator, I have tried about 400 games available on the net and have found 97% compatibility. - T/S2048 -- 16K RAM version of the 2068. - TC2048, TC2068 -- Upgraded Spectrum released in Portugal and Poland, popular in parts of Europe The TS2068 and TS2048 machines were renamed TC2068 and TC2048 (TC standing for Timex Computer). The TC2048 was a hybrid with a 16K Spectrum ROM and 48K RAM located in the HOME bank and a Spectrum compatible bus at the rear edge connector except for 2 or 3 signals. it used Timex's custom SCLD for control logic (like the TS2068), and had the advanced video modes of the TS2068. It didn't have the AY-3-8912 sound chip and the two joysticks interfaced with it, but instead was fitted with a built-in Kempston joystick. - QL (as in "Quantum Leap") 68008 main CPU, 8049 coprocessor for keyboard and I/O, a decent attempt at a "real" keyboard, 128K RAM, 48K ROM containing Sinclair Super BASIC and QDOS operating system. ROM and RAM are expandable. Connections include CPU expansion port, 2 RS-232 ports, TV and monitor, two joystick, 2 network ports, ROM port and a cartridge port. The QL has 2 microdrives built in and 6 additional drives could be connected. Microdrives use the same cartridges as Spectrum but incompatible format. A microdrive cartridge has space for about 110kB and an average access time of 3.5s. It has also two network ports for making a network of up to 63 QLs or a compination of QLs and Interface 1 Spectrums Sinclair released a 512K RAM expansion for this machine, and there were several different makes of disk drive interface available for it. The QL's working title was "ZX83", but was later changed. Evidence of this can be seen on the PCB - the two ULAs are labelled "ZX8301" and "ZX8302". - Z88 -- (marketed by Sinclair's new company - Cambridge Computers). The Z88 had 64K RAM, built in applications such as PipeDream (a word processor) and a spreadsheet, and the Z80 version of BBC BASIC for writing programs. It used proprietary EPROM-based cartridges for storage. Display was via a built-in SuperTwist LCD. RAM --- - Timex/Sinclair 1016 16K RAM pack expanded the ZX81 and T/S1000 to 16K, and the T/S1500 to 32K RAM. It used 16Kx1 dynamic RAM chips. MASS STORAGE ------------ NOTE: The terms "stringy floppy" and "wafer" are generic, and describe any continuous loop tape cartridge used for mass storage. One variant of it is the Sinclair Microdrive, which uses the AFAIK wafer. Another variant is the Entrepo type of wafer used by the Damco and the A&J Micro. - Timex/Sinclair 2020 Program Recorder was a cassette recorder with a tape counter and a VU/LEVEL meter to optimise cassette LOADing and SAVEing. - Interface 1 has a Microdrive wafer storage capacity. PRINTERS -------- NOTE: At this writing, it is opined that the Sinclair printers were compatible with all ZX/Spectrum/Timex busses. (Version 1.2) - Sinclair ZX Printer -- Used an aluminised paper for printing 32 columns. The paper has an aluminum layer on its surface which is conductive. The printer has two metal needles which go from left to the right (or right to left?) over the paper and where a black point should be the current to this needle is switched on and a spark jumps from the needle to the paper and makes a black point. - Timex/Sinclair 2040 Printer, AKA the Alphacom 32, was a 32 column line printer that used thermal paper for imaging. It is compatible with all Timex/Sinclair computer busses, including the Spectrum bus. Sinclair BASIC commands LPRINT and LLIST directed output to the printer, and COPY did a screen dump. MODEM ----- - The Timex/Sinclair 2050 modem, AKA the Westridge 2050 modem, was designed to be plugged into the expansion bus. It contains data, address and control lines, which are wired to the 8251 UART chip. The UART talks to 300 baud modem circuits. One hack for this is to sever the link between the UART and modem, then connect the UART to line driver/receiver chips, and bring the signals out to a standard RS-232 connector. I did this and the connector is installed in the box. A standard modem, or any other serial device can be plugged in to this port. I have even used it for packet radio (a ham radio digital mode), and with a null modem cable that was connected to an Amiga for file exchanges and terminal-to-terminal conversations. A terminal program called Specterm-64 can talk to the stock 2050 and also the 2050 with these mods and supports a speed of 1200 baud. INTERFACE --------- - Interface 1 has a RS 232 (DCE) Port (a little bit incomplete, a few lines were missing : DCD and DTR ???), two ZX NET-Ports for connecting up to an additional 63 Spectrums, and a slot for a microdrive. The Interface I uses three different I/O ports, and contains logic to page and unpage an 8K ROM if new commands are used. The ROM is paged if the processor executes the instruction at ROM address 0008 or 1708 hexadecimal, the error and close# routines. It is inactivated when the Z80 executes the RET at address 0700. - Interface 2 has two joystick ports (keys 1-5 & 6-0 equivalent, and a ROM slot. - Timex/Sinclair 1510 Command Cartridge Player was compatible with the ZX81, T/S1000 and T/S1500 bus. It allowed the use of ROM based software cartridges. - Timex/Sinclair 2090 Command Sticks were Atari/Commodore style digital joysticks that had an elongated base for holding in one hand while holding the stick in the other hand. The firing button was designed for thumb operation. VAPORWARE --------- NOTE: This section includes peripherals and options that may have been developed and prototyped, perhaps even some limited production, but never were available to the general public. By nature, some of this information may be rumor or apocyphal stories. It is still fascinating to wonder, what if? - ZX Spectrum Loki -- never released, specs as follows: Z80H running at 8MHz 256K RAM (?), Extended graphics modes, at least 256x192x16 colours, as well as the original Spectrum mode Amiga-style sound (4 x digital voices) Compatible with the 48K Spectrum (but not the 128) There was a big article on this in Crash magazine (in the UK - around the middle of 1986 or early 1987, just after the Amstrad takeover) The Loki designers went on to produce a games console which eventually materialised as the Konix console. There was also another project (reported in Crash and Sinclair User) codenamed "Pandora" - this was to be a portable Spectrum. After the Amstrad takeover, this was scrapped but eventually materialised as the Z88 (marketed by Sinclair's new company - Cambridge Computers). - BEU -- Bus Expansion Unit for the T/S2068. Was to plug into the expansion bus and offered bank switching RAM expansion, up to 16 MEGS, and buffering of bus signals so more peripherals could be plugged in. - T/S2080 printer -- Mannesman Talley dot matrix printer with bus interface - T/S2068 Disk Drive -- was submitted for FCC radio emission approval, used 3" disks, has two RS-232 ports, ROM/RAM and onboard CPU - T/S3068 Computer -- CPU and options unknown, but rumored to be competitive with the visionary Amiga line of computers. - THOR was CST's (a vendor of QL add-ons) attempt at a QL successor after the Amstrad sell-out. The original Thor, IIRC, was a QL motherboard, with RAM expansion/mouse/Centronics/floppy disk/PC keyboard interface board(s) in a metal desktop case (low-profile PC-like) with built in floppies (there was a hard-disk version too) and (I think) slightly hacked ROMs. It came with a psuedo-GUI called ICE in ROM which was a pale imitation of GEM. Alledgedly, it was based on a collaborative project between Sinclair and CST code-named Tyche which was in the works at the time of the sell-out. Later they announced a variant with a 68020 CPU (and optional 68881 FPU) as the Thor 20 (Thor 21) on a daughterboard. I doubt many of those were sold. Later still, they announced the Thor XVI, which had a new motherboard with a 68000 CPU, new video chip (16 colours I think) and an OS which was alledgedly a clean-room clone of Qdos, called Argos. According to magazine reports this turned out to contain ripped-off Qdos code. There were plans announced for the Thor XVI to be manufactured in Russia, but they came to nothing. Shortly after it was announced, the guy who ran CST fell out with his father (who ran the company which actually manufactured CST's hardware) and absconded to Denmark. The Danish company Dansoft got involved at this point, and an organisation called Thor International was formed. I don't think much happened after that. THIRD PARTY HARDWARE -------------------- Extra goodies to make you into a power Sinclair user! CLONES ------ - MICRO ACE (USA) -- a copy of ZX80 (no clone, but piracy) 4K ROM, 1K RAM - CZ1000 (CZERWENY ELECTRONICA, Argentina) The argentinan version of ZX81/ TS1000 - TK82, TK83 (MICRODIGITAL, Brazil) The brazilian version of ZX81/TS1000 - CZ1500 (CZERWENY ELECTRONICA) The argentinian version of TS1500 - TK85 (MICRODIGITAL) An improved version of TS1500 (TK83) With 10K ROM, 16K RAM, joystick port, SPECTRUM-style case with rubber keyboard, two speeds for SAVE and LOAD: 300 & 4200 baud. - TK90X (ZX Spectrum brazilian clone) Technical details include: * Z80A Processor (3.58MHz) * 16kb ROM, Spectrum similar with added TRACE command and UDG editor with Portuguese characters in UDG area * 16kb or 48kb RAM * 24x32 Screen text * 8 Colors * 176x256 Graphic resolution * Tape-drive 1200 baud * Joystick interface, compatible with i/f 2 Manufacturer: Microdigital Av. Angelica, 2318 Quarto andar Sao Paulo - SP - Brazil 01228-000 - TK-95 An upgraded TK-90X with a real keyboard and an improved ROM that had the features that the TK-90X ROM offered, but it was more compatible with the standard Spectrum. - POWER 3000, LAMBDA, PC8300 These far east products seem to be identical. They have improved keyboard facilities, you can type in each BASIC command letter by letter, the soft rubber keyboard has two SHIFT and one RESET key. With 8K ROM, 2K RAM, joystick port, monitor and TV output, sound, minor changes in the character set for playing games, no RAM clearing after RESET. A color-module was sold for LAMBDA (it works on ZX81, ask ZX-TEAM) - ZS SCORPION, designed in Russia, it has the following hardware: * 256KB RAM * 64KB to 256KB ROM * All interfaces (RS232, Centronics, Diskcontroller etc) * 7MHZ Z80B Processor (with switchable turbo mode on/off) * fully compatible with speccy 128 * build-in monitor-debugger on NMI and many tools * TR-DOS disk system * can be attached hard disk (IDE) and videoprocessor The TR-DOS system is a standard in Russia, Latvia, Ukraine etc. All this costs about $200 (with one floppy drive, 64KB RAM, NMI monitor, 256KB RAM, 7MHZ, without monitor). MASS STORAGE ------------ - JLO (Oliger) disk interface. Supports IBM drives & uses WD1770 controller. DOS is in an EPROM that is bankswitched into the 0-8K area in a similar manner as is done with Sinclair's IF1. Commands are the same as in BASIC, but you add a "/" after them. EG: LOAD /"my program". Comes with Centronics printer driver that lets you copy, llist and lprint to large printer through the AERCO or JLO Centronics interface. Also comes with an NMI button that lets you do a state save (like an SNA), copy screen to printer or disk, break to basic, reset, etc. Uses none of the computer's memory. Stores files sequentially. - FDD3000 dual 3" disk system from Timex of Portugal has its own Z80 processor and its own local 64K of memory. CP/M 2.2 was (is) available for it. This thing has a Spectrum connector and was designed for the TC2048. - Zebra disk drive system -- for T/S 2068, made from parts they clearly purchased from the Portugal Timex. It has an Amdek 3" mechanism in a box that matches the Timex silver scheme, the drive controller in another box, and the power supply in yet a third box. A smaller interface box attached to the rear port of the 2068 and has a reset button. The disk drive controller also provides two RS-232 ports. Apparently, the Portuguese Timex had a Spectrum compatible bus (which the US 2068 does not). Zebra made a card that plugs between the 2068 and the disk interface and converts the bus to work with the disk drive. It provides an extension of the Timex bus as 90 degrees to the 2068. Zebra planned to provide a real RGB interface: the traces are on the card and the manual mentions the RGB capacity. While the Amdek 3" seems to have a standard 34 pin edge connector. I've tried to hook a 5 1/4" up to the second connector in the ribbon cable to no avail. - Ramex Millenia K disk i/f -- for the T/S2068, the included SP-DOS would format a disk to 820K, uses standard drives: DS/QD - Aerco disk system -- for 2068, uses WD1770 controller. Supports up to 4 IBM drives of any size/density, RGB i/f, optional parallel or dual RS-232 ports. Has 64K RAM bank which can run CP/M. Models also available for ZX81-T/S1000 - A&J Microdrives -- Model 1000 for ZX81-T/S1000, Model 2000 for T/S 2068. An interface that plugs into the computer expansion bus, offers a parallel port and ports for up to 2 "stringy floppy" or "wafer" drives. The Model 2000 has a Stringy Operating System (SOS) in an EPROM mapped into the extension ROM address. The SOS is called when a filename is preceded by the "@" character. Wafers were available in sizes from 14K to 85K. Data is loaded at approximately 11,000 baud. If the program was well matched to the wafer, the load time compared favorably to many disk systems such as the Commodore 64 and Atari 8-bit computers had. - Rotronics Wafadrive -- Designed for 16K and 48K Spectrum, plugs into expansion bus, offers parallel and RS-232 ports, this unit is a box with two wafer drives built in. The Wafer Operating System (WOS) is contained in an EPROM that is mapped into the Spectrum 0-8K address. An extended BASIC that supports the CAT, OPEN, CLOSE, FORMAT and ERASE commands is part of the WOS. Wafers were available in 16-64-128K sizes. Load speed: 18,000 baud. A version of this was made for the T/S2068 and included an Omni/Emu Spectrum emulator card. - Larken disk system -- The Larken system has an expansion interface card that uses a WD1770 controller, and a firmware card. The i/f card has a pushbutton NMI save for producing RAM snapshots, a Kempston compatible game port and a card edge for connecting standard 34 conductor disk drive cable. Standard 5-1/4 and 3-1/2" drives are usable with this system, and format to 400K and 800K each. Drive power supply must be furnished extra. Up to four drives are supported by this system. The firmware card plugs into the cart port, has an 8K LKDOS EPROM and an 8K RAM for storing variables, fonts and MC routines. A socket in the card is mapped so that a Spectrum ROM can be plugged in and used. An extended BASIC supports the disk system, and also provides for screen pattern fills, color change without clearing contents, windows and proportional fonts, as well as redirecting output through the use of streams and channels. The computer may execute an AUTOSTART program from disk upon booting up. The Larken system is Spectrum compatible, and supports the Aerco and Oliger disk formats. - Larken RAMDISK -- uses 32K RAM chips mapped into the 32-64K address space of the cart port for up to 256K of RAM. LKDOS is designed to treat this as a RAM Disk and can load and save files to this RAM. RAM can be non-volatile and AUTOSTART can boot from RAM disk. MODEM ----- - Byte Back MD-2B modem -- ZX81-T/S1000 compatible, direct connect, with RS-232 interface, this module plugs into the expansion connector. RAM --- - Byte Back 64K RAM -- Battery back up, ROM socket, can copy system ROM into RAM for modification and customizing. - Hunter non-volatile RAM -- can be mapped for anywhere from 0-32K, ideal for 8-16K ZX81, T/S1000 address. Uses 2K CMOS low power RAM, onboard backup battery, can also use EPROM. - Memopak 16-32-64K RAM -- ZX81, T/S1000 compatible, designed to piggyback with other devices plugged into the expansion bus INTERFACE, SOUND, SPEECH ------------------------ - Memopak parallel i/f -- ZX81-T/S1000 compatible, plugs into expansion port, resident software supports ASCII - Byte Back BB1 Control Module -- ZX81-T/S1000 compatible, plugs into system bus, has 8 relays and 8 TTL inputs - FD-ZX1 I/O board -- ZX81-T/S1000, Spectrum compatible, data acquisition and control board, available as a kit - Winky Board -- plugs inline between cassette Ear jack and computer, conditions load signal for more reliable loading - SRS1000 for ZX81, T/S1000 - SRS2000 for 2068 -- speech recognition recognizes up to 8 spoken words for voice command of computer system. - William Stuart Systems -- I/O port that supports a speech recognition system, a 3 channel music synthesizer and a phoneme based speech synthesizer. Each unit was available separately. for ZX81, T/S1000 - Zebra Talker -- ZX81-T/S1000 compatible, has the Votrax SC01 phoneme chip, 1400 word Votrax dictionary, optional speaker amp - ZON X81 -- gives the ZX81, T/S1000, and Spectrum a 3 channel, 8 octave sound chip. Draws power from computer, built inspeaker, I/O mapped. - Blippo sound generator -- ZX81-T/S1000 compatible, speaker extra - Zebra keyboard beeper -- ZX81-T/S1000 compatible, audio feedback of keypress - Zebra light pen -- ZX81-T/S1000 compatible, i/f, pen, software - Zebra joystick adaptor -- ZX81-T/S1000 compatible, connect Atari type stick to computer, with instructions for adapting software - ScreenMate light pen and joystick adaptor -- ZX81-T/S1000 compatible - Gamesmate -- gives T/S2068 a Kempston compatible i/f for some Spectrum games plugs into cart port - Zebra Graphics Tablet -- Koala tablet with T/S2068 i/f and paint software that supports the Extended Color mode (256X192, 1X8 pixel attributes) - Memopak High Resolution Graphics -- for ZX81, T/S1000, with a 2K EPROM firmware to support a 248X192 pixel bitmapped display page. Multiple pages supported, limited by available RAM (6.5K per page) KEYBOARDS --------- - Byte Back keyboard -- 41 keys, including space bar, no case, T/S legends - Memotech Keyboard -- 40 keys, T/S legends on keys, aluminum case - Kradle -- ZX81-T/S1000 compatible, a case, raised keys, 64K RAM, pilot light, Joystick connector, cassette filter, all rolled into one. Optional RS-232 and parallel i/f - Secondbase key overlay -- for ZX81-T/S1000, raised rubber chiclet keys fit over membrane keyboard for a more tactile feel Alternate ROMs and Emulators ---------------------------- - ROM switches allow the user to Spectrumize the T/S2068 for access to the larger quantity of software for the Spectrum. A few programs are still incompatible because of the different bus loading schemes the two computers used. Two kinds of ROM switches are available. The RUSSELL ELECTRONICS ROM switch is installed internally with an external switch. The system bus is unchanged. The DAMCO ROMswitch plugs into the system bus and has the resistors on board so if the Spectrum ROM is selected the bus is also loaded properly so as to be Spectrum compatible. - Multi FORTH -- an EPROM with FORTH operating environment and a switch so the Sinclair ROM can also be invoked. CONTRIBUTORS: ------------- Contributors to this factsheet include these fine Sinclair afficianados: Kurt.Prochnow@pebble.cts.com pns@zodiac.unl.ac.uk (Paul Squires) sealbrec@acs.ucalgary.ca (Alvin Albrecht) Simon J Raybould (sie@ftel.co.uk) davidh@lsl.co.uk tec2@acsu.buffalo.edu (Thomas E Callahan) m@mbsks.franken.de (Matthias Bruestle) tvdm@uni-muenster.de vacquier@138.145.209 (Marco Vacquier) ali%wgd562.wg.uk.sbphrd.com@sb.com (Alastair Booker) [big thanks!] p.liebert@t-online.de (Peter Liebert-Adelt/ZX-TEAM-MAGAZIN) Sj50191@lvrulv11.lanet.lv Maxluppe@ifqsc.sc.usp.br St@epcc.ed.ac.uk Also of note: Sinclair ZX Spectrum FAQ, v.2.4a Maintained by Marat Fayzullin [FMS] email: fms@wam.umd.edu available at: http://www.cs.umd.edu/users/fms/ A final thanks to: Uncle Clive!