The TI-99/4A is a redesign of the previous TI-99/4 system, which was discontinued from production. The new TI/99″4A" has an improved graphics chip and a higher quality keyboard.

Texas Instruments released the computer in June 1981 with a starting price of $$525, excluding monitor.

The only way to expand the original TI-99/4A is from the expansion port on the right side of the computer.

Memory expansion, a serial interface, a floppy disk drive and other peripherals could be connected to this port to increase the computer's capabilities. This chain of peripherals and expansions could be very long, as you can see in the picture of the original TI-99/4.

To solve this problem, Texas Instruments created a Peripheral Expansion Box that provides a more efficient way to expand the TI-99/4A. This expansion box is large, solidly built and of high quality.

Introduced in January 1982, the Peripheral Expansion Box cost $1475, including:

• A disk controller card and a SS/SD floppy disk drive
• RS-232 serial interface card
• 32Kb memory expansion card

It is estimated that one peripheral expansion box was sold for every ten TI-99/4A computers sold. Inside this peripheral box there is space for 8 expansion cards. One of these slots is intended to contain the interface card that connects to the computer via a flat cable.

The open peripheral expansion box shown has the interface card, an RS-232 serial card, a 32Kb RAM expansion and other disk drive controller cards installed.

The manufacturer CorComp brought to market many of its own expansion cards and peripherals for the TI-99/4A computers. The Micro-Expansion CC-9900 for IT was launched in May 1984.

This system is a compact and much smaller unit, which connects to the expansion bus on the right side of the TI 99/4A and contains the same features as the default configuration of the expansion box manufactured by Texas Instruments and even more:

• Parallel port
• Serial interface
• 32Kb RAM expansion
• Diskette drive interface

The manufacturer CorComp filed for bankruptcy a few months later, in August 1984.

At about the same time, Milton Bradley announced a futuristic Milton Bradley Expansion System (MBX) for the TI-99/4A computers, which offered speech synthesis and speech recognition, when used with specific Milton Bradley cartridges. After initial training, the MBX system recognises specific commands spoken into the microphone, as well as keyboard and joystick input.

The joystick of the MBX system allows 360-degree movements in addition to the typical up and down, left and right movements, it also rotates like the volume knob.

In August 1982, Texas Instruments begins to lose shelf space to its competitors, and issues a $100 discount on TI-99/4A computers.

By the end of 1982 the TI-99/4A is the number one home computer in America, with approximately 35% of market share, and produces 150,000 computers per month.

In January 1983, TI announced that the TI-99/2 computer would be sold for only $100. Having little in common with the 99/4A, the 99/2 was to be a cheap entry-level computer like the Timex Sinclair 1000.

In February 1983, in order to remain competitive, TI again cut the price to dealers, and the cost of a TI-99/4A dropped to about $150.

In June 1983, TI launched a cheaper version of the beige plastic TI 99/4A computer, reducing the retail price, this time to less than $100.

The new beige TI-99/4A has a new design and is more economical. After the beige model was launched, all the new cartridges for TI-99/4A were also of the same colour.

At this time Texas Instruments was selling computers for less than it cost to manufacture them. As a result, Texas Instruments experienced a $100 million loss in the second quarter.