--- title: Texas Instruments TI 99 / 4A categories: - Computers types: - Home Computer origins: - U.S.A. years: - '1981' cpus: - TI TMS 9900 params: name: TI 99 / 4A image: /media/museum/photos/texas-instrument_ti994a_1.jpg company: /companies/texas-instruments company_name: Texas Instruments specs: - label: NAME value: TI 99 / 4A - label: MANUFACTURER value: Texas Instruments - label: TYPE value: Home Computer - label: ORIGIN value: U.S.A. - label: YEAR value: '1981' - label: END OF PRODUCTION value: '1984' - label: BUILT IN LANGUAGE value: TI Basic - label: KEYBOARD value: |- QWERTY full-stroke keyboard, 48 keys\ 2 x SHIFT, CTRL, ALPHA LOCK, FCTN - label: CPU value: TI TMS 9900 (with 256 bytes 'cache', actually it accesses to 256 bytes of RAM) - label: SPEED value: 3,3 MHz - label: CO-PROCESSOR value: TMS 9918 (TMS 9929 in Europe) - Video / Sprite - label: RAM value: '16 KB - Memory expansion card can be added : 4 KB or 32 KB (up to 52 KB)' - label: VRAM value: 16 KB - label: ROM value: '26 KB  : 8 KB ROM connected to the CPU + 18 KB ROM in byte-serial bit-mapped circuits (usually known as GROM, Graphic Only Memory)' - label: TEXT MODES value: 32 x 24 (16 colors), 40 x 24 (2 colors) - label: GRAPHIC MODES value: |- Multicolor mode : 48 x 64 with 16 colors\ 256 x 192 with 16 colors (only accesed via machine code)\ Sprites (only with TI-Extended Basic) - label: COLORS value: '16' - label: SOUND value: 3 channels, 5 octaves (110hz to 55khz) and 1 noise channel (periodic and white) - label: SIZE / WEIGHT value: 38 x 25,5 x 6 cm / 2,15 kg - label: I/O PORTS value: Tape interface, RGB video, Joystick (2), cartridge slot (Solid State Cartridge) - label: OS value: TI's own system, but a p-code card could be added, which gave access to the UCSD p-system and a Pascal compiler. - label: POWER SUPPLY value: |- Special TI external PSU\ (pins 1,2 : 16v / 1,6A -- pins 2,4 : 8v / 0,15A) - label: PRICE value: £99 (UK, 1983) tabs: - photos - adverts - hardware - emulators - links - docs - videos forum_thread: 246 photos: - title: SIDE VIEW subtitle: '' text: Notice the expansion port on the right side. image: /media/museum/photos/texas-instrument_ti994a_side-r_1.jpg - title: VIEW FROM ABOVE subtitle: '' text: The whole right part is the cartridge slot (Solid State Sotfware slot). image: /media/museum/photos/texas-instrument_ti994a_above_1.jpg - title: VIEW FROM UNDER subtitle: '' text: Ok,it's not that interesting, but hey, who knows ? Maybe someone's interested out there... image: /media/museum/photos/texas-instrument_ti994a_under_1.jpg - title: FRONT VIEW subtitle: '' text: '' image: /media/museum/photos/texas-instrument_ti994a_front_1.jpg - title: PROFILE subtitle: '' text: There is the joystick plug, so alone... image: /media/museum/photos/texas-instrument_ti994a_profile_1.jpg - title: LEFT SIDE subtitle: '' text: I guess you can spot the joystick plug ?! image: /media/museum/photos/texas-instrument_ti994a_side-l_1.jpg - title: RIGHT SIDE subtitle: '' text: You can easily spot the expansion port. image: /media/museum/photos/texas-instrument_ti994a_side-r_2.jpg - title: REAR subtitle: '' text: |- From left to right we have : \- Cassette interface (DB9 !)\ \- Power IN\ \- RGB video out (DIN6) image: /media/museum/photos/texas-instrument_ti994a_rear_1.jpg - title: COMPLETE SYSTEM subtitle: '' text: |- Complete system with expansion box and vocal syntesizer module Thanks to **Blake Patterson** image: /media/museum/photos/ti_ti994a_completesystem_1.jpg adverts: - title: U.S. ADVERT (1982) subtitle: '' text: |- Advert said: Our Peripheral Expansion System gives you plug-in cards for memory expansion, P-Code capabilities, a disk drive controler and the RS-232 interface. You can also add a modem, speech synthetiser, disk drive and matrix printer... ... TI BASIC is built into the computer, but it can also handle TI Extended BASIC, UCSD Pascal, TI LOGO, TMS-9900 Assembly language and TI PILOT ... image: /media/museum/pubs/ti_ti994a_pub_1.jpg - title: UK ADVERT (STUPID !) subtitle: '' text: |- Dated august 1982 Thanks to [Howard Jones](http://wotsit.thingy.com/haj/) for this picture. image: /media/museum/pubs/texas-instrument_ti994a_pub_1.jpg - title: FRENCH AD (JAN. 1983) subtitle: '' text: |- "TI 88/4A. The family computer.\ It's easy. Connect it, connect yourself." image: /media/museum/pubs/ti_ti994a_pub_jogger.jpg - title: FRENCH AD (SEPT. 1983) subtitle: '' text: |- "The amazing TI-99/4A.\ A computer for 1800fr" image: /media/museum/pubs/ti_ti994a_pub_incroyable-1800fr.jpg - title: FRENCH ADVERT subtitle: '' text: |- *Texas Instruments home computer, simply unbeatable* Notice that the man seems not to feel at ease with a computer keyboard and still doesn't use the right finger... Thanks to **Charles da Silva** image: /media/museum/pubs/ti_ti994a_pub_imbattable.jpg - title: UK ADVERT, OCT 1983 subtitle: '' text: Probably the last advert made by T.I. in the UK image: /media/museum/pubs/ti_ti994a_pub_s2.jpg - title: UK ADVERT, OCT 1983 subtitle: '' text: Last sales in the UK. At the same time, a Commodore VIC-20 cost £139 and a Commodore 64 cost $229 image: /media/museum/pubs/ti_ti994a_pub_s1.jpg hardware: - title: COMPLETE SYSTEM... subtitle: '' text: TI-994A with expansion box, vocal synthesizer and acoustic coupler. image: /media/museum/hardware/texas-instrument_ti994a_complete.jpg - title: 5''1/4 DISK-DRIVES subtitle: '' text: On this picture, there is two 5''1/4 disk-drives (or maybe just 1 with its controller). This particular setup is quite rare since different drives were produced to be included into the popular expansion box. image: /media/museum/hardware/texas-instrument_ti994a_diskdrives_1.jpg - title: TI-99/4 COLOR MONITOR subtitle: '' text: '' image: /media/museum/hardware/texas-instrument_ti994_color-monitor.jpg - title: TI-99/4 PRINTER subtitle: '' text: This Dot matrix printer was a rebadged version of the Epson FX-80 image: /media/museum/hardware/ti_ti994a_printer_1.jpg emulators: - title: Mess emulator url: http://www.mess.org platform: MS DOS text: Emulates all of the TI-99 versions, including the Geneve card - title: PC99 url: http://pw2.netcom.com/~mjmw/index.html platform: MS DOS text: Quality emulator for the TI 99/4A - title: Classic99 url: http://www.harmlesslion.com/software/Classic99 platform: Windows text: Open Source & freeware TI-99/4A emulator for Windows 9x - title: Win994a url: http://www.99er.net/win994a.shtml platform: Windows text: Win994a is a TI-99/4A simulator written by Cory Burr that installs and runs in Windows - title: MacV9T9 official homepage url: http://perso.club-internet.fr/pytheas/english/MacV9T9.html platform: Apple text: MacV9T9 is a TI99 emulator for the Macintosh links: - title: planet-99.net url: http://www.planet-99.net/ text: Lots and Lots of 4A software on this site. Disks, Cartridges, Articles - the lot! - title: Somtimes url: http://sometimes.99er.net/ text: Demo cartridges - title: TI-99 4/A Webring url: http://e.webring.com/hub?ring=ti994a text: You know what it is ;-) - title: TI-99 Forever ! url: http://www.ti99.com text: Excellent site by Fabrice Montupet - title: TI-99/4 Home Page at 99er.Net url: http://www.99er.net/ text: THE us site to visit ! - title: Web Wiz CAPTCHA url: http://www.webwizcaptcha.com text: Tons of things here ! docs: - title: USER'S REFERENCE GUIDE url: http://www.classiccmp.org/dunfield/ti/index.htm cover: /media/museum/docs/couvs/texas-instruments_ti99-4a_user-reference-guide.jpg text: |- [**USER'S REFERENCE GUIDE**](http://www.classiccmp.org/dunfield/ti/index.htm)written by Texas Instruments  compiled/archived by Dave Dunfield\  type of document : PDF\  source : [Daves Old Computers](http://www.classiccmp.org/dunfield/) - title: BEGINNER'S BASIC url: http://www.classiccmp.org/dunfield/ti/index.htm cover: /media/museum/docs/couvs/texas-instruments_ti99-4a_beginners-basic.jpg text: |- [**BEGINNER'S BASIC**](http://www.classiccmp.org/dunfield/ti/index.htm)written by Texas Instruments  compiled/archived by Dave Dunfield\  type of document : PDF\  source : [Daves Old Computers](http://www.classiccmp.org/dunfield/) - title: BASIC REFERENCE CARD url: http://www.classiccmp.org/dunfield/ti/index.htm cover: /media/museum/docs/couvs/texas-instruments_ti99-4a_basic-reference-card.jpg text: |- [**BASIC REFERENCE CARD**](http://www.classiccmp.org/dunfield/ti/index.htm)written by Texas Instruments  compiled/archived by Dave Dunfield\  type of document : PDF\  source : [Daves Old Computers](http://www.classiccmp.org/dunfield/) - title: GETTING STARTED WITH THE TEXAS INSTRUMENTS TI99/4A url: http://shawweb.myzen.co.uk/stephen/book.htm cover: /media/museum/docs/couvs/vide.gif text: |- [**GETTING STARTED WITH THE TEXAS INSTRUMENTS TI99/4A**](http://shawweb.myzen.co.uk/stephen/book.htm)written by Stephen Shaw  compiled/archived by Stephen Shaw\  type of document : HTML\  source : [Stephen's Main Web Page](http://shawweb.myzen.co.uk/stephen) - title: PROGRAMMING DISCOVERY IN TI BASIC STUDENT GUIDE url: http://www.99er.net/docs.html cover: /media/museum/docs/couvs/texas-instruments_ti99-4a_programming_discovery.jpg text: |- [**PROGRAMMING DISCOVERY IN TI BASIC STUDENT GUIDE**](http://www.99er.net/docs.html)written by Texas Instruments Computer Advantage Club  compiled/archived by Rich at www.99er.net\  type of document : Unknown\  source : [TI-99/4A Home Computer Page](http://www.99er.net/) - title: TI-99/4 CONSOLE SCHEMATICS url: http://www.99er.net/docs.html cover: /media/museum/docs/couvs/texas-instruments_ti99-4_console-schematics.jpg text: |- [**TI-99/4 CONSOLE SCHEMATICS**](http://www.99er.net/docs.html)written by Texas Instruments  type of document : PDF\  source : [TI-99/4A Home Computer Page](http://www.99er.net/) - title: TI-99/4A CONSOLE & PERIPHERAL EXPANSION SYSTEM TECHNICAL DATA url: http://www.99er.net/docs.html cover: /media/museum/docs/couvs/texas-instruments_ti99-4a_technical_data.jpg text: |- [**TI-99/4A CONSOLE & PERIPHERAL EXPANSION SYSTEM TECHNICAL DATA**](http://www.99er.net/docs.html)written by Texas Instruments  type of document : PDF\  source : [TI-99/4A Home Computer Page](http://www.99er.net/) - title: SPEECH SYNTHESIZER MANUAL url: http://www.99er.net/docs.html cover: /media/museum/docs/couvs/texas-instruments_ti99-4a_speech-module-manual.jpg text: |- [**SPEECH SYNTHESIZER MANUAL**](http://www.99er.net/docs.html)written by Texas Instruments  type of document : PDF\  source : [TI-99/4A Home Computer Page](http://www.99er.net/) - title: DISK MEMORY SYSTEM MANUAL url: http://www.99er.net/docs.html cover: /media/museum/docs/couvs/texas-instruments_ti99-4a_disk-memory-system.jpg text: |- [**DISK MEMORY SYSTEM MANUAL**](http://www.99er.net/docs.html)written by Texas Instruments  compiled/archived by Rich at www.99er.net\  type of document : Unknown\  source : [TI-99/4A Home Computer Page](http://www.99er.net/) - title: RS232 INTERFACE CARD MANUAL url: http://www.99er.net/docs.html cover: /media/museum/docs/couvs/texas-instruments_ti99-4a_rs232.jpg text: |- [**RS232 INTERFACE CARD MANUAL**](http://www.99er.net/docs.html)written by Texas Instruments  compiled/archived by Rich at www.99er.net\  type of document : Unknown\  source : [TI-99/4A Home Computer Page](http://www.99er.net/) - title: DATA RECORDER MANUAL url: http://www.99er.net/docs.html cover: /media/museum/docs/couvs/texas-instruments_ti99-4a_data-recorder.jpg text: |- [**DATA RECORDER MANUAL**](http://www.99er.net/docs.html)written by Texas Instruments  compiled/archived by Rich at www.99er.net\  type of document : PDF\  source : [TI-99/4A Home Computer Page](http://www.99er.net/) videos: - title: TV commercial featuring Bill Cosby url: https://www.youtube.com/watch?v=OhsgvW9P7tI text: 'Length: 30 s' related: - /museum/texas-instruments-computer-99-8 - /museum/texas-instruments-ti-99-2 - /museum/texas-instruments-ti-99-4a-beige oc_id: 236 source: url: https://web.archive.org/web/20230610144042/http://www.old-computers.com/museum/computer.asp?c=236 date: '2023-06-10' --- The Texas Instrument [TI 99/4A](/museum/texas-instruments-ti-99-4a/) was a very succesful computer. A large number ROM cartridges (36 KB each) were developped for this computer, as the popular Extended Basic. Up to seven peripherals could be connected : 32 KB RAM extension, RS232c, Disk controler (90 KB per disk, up to 3 disk-drives), speech synthetiser, Peripheral Expansion box, and so on... One item of note is that the bus architecture for the Peripheral Expansion box (PE) was the basis for the NuBus used in the later Macintosh computers. --- **Contributors** : Stephen Boutillette **Ben Yates** says :\ The TI VDP had 16K of dedicated VRAM, outside of the CPU RAM memory map.\ The 99/4A has 4 VDP modes :\ 1\. Graphic I (32x24, 255 redefineable characters, 16 colors, 1 background and 1 foreground color for each character set of 8 characters, 8x8 character matrix)\ 2\. Text mode (40x24, foreground/background colors out of 16)\ 3\. Multicolor (weird 48 x 64 mode, 4x4 unicolor character matrix)\ 4\. Bitmap - same as 1, except 768 characters and each character can have a foreground and background color (of 16) for each pixel row of that character. **David Stites** adds:\ You list the TI 99/4a as being released in June 1979. At about that time I purchased a TI 99/4 for around $700. Besides the built-in BASIC and the firmware cartridges it had a third function called an Equation Calculator. I never used it and when the computer went insane they replaced it with the /4a for $50. The /4a didn't have the Equation Calculator.