Texas Instruments TI-99
Texas Instruments has always been a leader in microprocessor technology. After a few years as a top manufacturer of electronic calculators using their custom microprocessor technology, and a foray into minicomputer systems using their 16-bit TI-990 processors, Texas Instruments decided to throw its hat into the ring of the home computer market in 1979 with the TI-99 computer system.
|Listen to our podcast episode about the TI-99 computer here|
The first TI-99 was called the TI-99/4. It had a chicklet style keyboard that looked more like Texas Instruments calculator buttons than an actual typewriter style keyboard. Outside of its odd keyboard, It’s features were comparable to other home computer systems of the day, except it used a 16-bit TMS-9900 microprocessor, and cost $1150. However, that price included a modified 13-inch Zenith television which worked solely as a color monitor.
The TI-99/4 did not fit into the market very well and had poor sales. The entry price was considered rather steep, especially since people found they could just hook it up to any composite monitor available elsewhere. So, some revisions were made to its design and configuration. A pull here, a tweak there, and the result was the TI-99/4A computer released in 1981, commonly referred to as the TI-99.
The new TI-99 sported 16K of RAM, a TMS 9900 CPU running at 3 MHz., a custom TMS9918A Video Display Chip, and a 48 key keyboard with full typewriter style keys. It sold without the monitor for literally half the price of the TI-99/4, or $525, but included an RF modulator that allowed you to connect it to a TV. The newly revamped keyboard shared the slightly diminished dimension of the TI-99/4 keyboard. It wasn’t a bad keyboard, but it was a bit cramped.
To the right of the keyboard was the cartridge slot which was used to insert one of many patented Solid State Cartridges for gaming, programming, and utility needs. This had not changed from the earlier /4 version. Texas Instruments actually banked on the idea that people wanted the use of their computer to be as simple as possible, so they marketed just about all of their software line as a plug-in Solid State Software cartridge. The problem with that philosophy was that the costs involved making the cartridges made the software more expensive than comparable software sold on disk for other brands of home computers.
The system specs for the TI-99/4 and 4A are as follows:
- CPU: TMS9900 16-bit
- RAM: 16 kB
- ROM: 26 kB
- Video: 32×24 character display, 256 x 192 bitmapped
- Sound: 3 channel tone generator with optional speech syntesis
- Ports: Joystick, composite video out, cartridge slot, expansion port, cassette port
- 48 key chiclet keyboard (TI-99/4), 48 key standard keyboard (TI-99/4A)
The TI-99/4 had numerous and relatively capable expansion options, which would also work on the 4A. But they were rather costly. Expansion was achieved through a side port on the computer. You could buy a number of external devices, called “sidecars”, The available sidecars were:
- Speech synthesizer: $150
- RS-232 with modem: $225
- Thermal printer: $400
- 32K memory expansion: $400
- Disk controller: $300
- Disk drives: $500 each
All of these would “sidecar” with up to five others out from the right hand expansion slot. If you owned all sidecar devices, you would have your TI-99 on the desk with a long extension of devices sticking out from its right side.
After the 4A version was released, a huge and heavy box called the Peripheral Expansion Box, or PEB, was released. This provided a more sensible, modular expansion form factor. It connected to the TI-99 by a large insulated ribbon cable referred to as the “fire hose.” The expansion box resembled an S-100 type of expansion in that it contained a power supply, and expansion cards were placed into expansion slots as desired. The expansion cards were purchased separately and were specifically designed for the PEB. The PEB could house one or two disk drives to be used in conjunction with the drive controller card. A typical desktop configuration for the PEB kit was to have the TI-99 sit in front of the PEB and the TV or monitor on top of the PEB.
By late 1982, Texas Instruments found themselves in a home computer price war. Commodore computers were packing a lot of features and seemed to be dropping their prices at regular intervals. Texas Instruments couldn’t keep up, but still competed in this price war by offering rebates and other deals. They even pushed a service called “The TI Computer Advantage Club” in major metropolitan areas in order to get families interested in using the TI-99 as a family computer.
But still hoping that they could make money on their Solid State Software modules, the TI-99 became a “loss leader” until an over $100 Million loss over the product in mid-1983 forced them to proceed in discontinuing the TI-99. The price was cut so low that retailers were able to sell them for about $50 around Christmas time. The TI-99 was officially discontinued by Spring of 1984.
In 1983, Texas Instruments had discovered a shock hazard with their transformer power supply. TI-99 computers used a small, inline transformer for external power, with the rest of the power supply inside the computer itself. The transformers could begin to overheat and create a shock hazard for the user if they touched an input port or the RF modulator. To correct the problem, Texas Instruments offered a free inline-fuse adapter. It looks like a very short extension cord with a box inline. The box contains a fuse that would blow in the case of a transformer short.
Like a phoenix, the TI-99 was reborn through efforts from members of users groups, programmers, and hardware designers. The machine was actually quite capable and many believe Texas Instruments shot themselves in the foot by limiting their primary software line to cartridges, and restricting access to the system’s hidden capabilities. In 1987, a company called Myarc created a special card that plugged into the PEB, called Geneve 9640. The Geneve was basically a “computer on a card” and ran on a 12MHz TMS9995 processor and has an 80 column output. It ran almost all TI-99 software, but used an IBM XT keyboard for input.