TI-99

Texas Instruments TI-99/4

1979 TI-99/4 with RF modulator, optional Speech Synthesizer, keyboard overlays, and a cartridge
Type	Home computer
Release date	June 1981 (99/4 in October 1979)
Discontinued	October 1983
Operating system	TI BASIC
CPU	TI TMS9900 @ 3.0 MHz
Memory	256 bytes "scratchpad" RAM + 16 KB VDP (graphics RAM)

The Texas Instruments TI-99/4A is a home computer, released June 1981 in the United States at a price of $525 ($1,383 adjusted for inflation). It is an enhanced version of the less successful TI-99/4 model, which was released in late 1979 at a price of $1,150 ($3,795 adjusted for inflation).

The TI-99/4 has a calculator-style chiclet keyboard and a character set that lacked lowercase text. The TI-99/4A added an additional graphics mode, "lowercase" characters consisting of small capitals, and a full-travel keyboard. Both use 16-bit processors, making the TI-99/4 series the first 16-bit home computers.

The TI-99/4A's CPU, motherboard, and ROM cartridge ("Solid State Software") slot are built into the keyboard. The power regulator board is housed below and in front of the cartridge slot under the sloped area to the right of the keyboard. This area gets very hot so users commonly refer to it as the "coffee cup warmer." The external power supply, which was different according to the country of sale, is a step-down transformer.

Available peripherals included a 5¼" floppy disk drive and controller, an RS-232 card comprising two serial ports and one parallel port, a P-code card for Pascal support, a thermal printer, an acoustic coupler, a tape drive using standard audio cassettes as media, and a 32 KB memory expansion card. The TI-99/4 was sold with both the computer and a monitor (a modified 13" Zenith color TV) as Texas Instruments could not get its RF modulator approved by the U.S. Federal Communications Commission in time. The TI-99/4A did ship with an RF modulator.