Files
website/content/museum/texas-instruments-ti-99-4a.md
T
yann64andClaude Opus 5.5 b274874139 All machines linked to their forum thread (full comment import)
1,289 discussions, 9,527 archived comments; pages no longer carry the comments themselves.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YDRjtmAiNpo5mK5N3d7QwZ
2026-10-13 17:26:43 +02:00

358 lines
14 KiB
Markdown
Raw Blame History

This file contains invisible Unicode characters
This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
---
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.