This is an interesting advertisement ... here is the translation (I try to mimic the somewhat odd wording from those days):
Programmed for versatility
"Video computer" is what Texas Instruments calls its console with keyboard, slot for software modules and connectors for external devices (periphery). But let us first have a look at the "inner life" of the console:
One crucial aspect of using your video computer system should be the question of freely available memory capacity - the working memory. The space which one can work with is an outstanding 16 K Byte RAM on the TI99/4A that can be expanded up to 48 K Byte.
By using the SolidStateSoftware modules, memory is not "loaded", neither by transfering, nor by cumbersome reading: The CPU directly accesses the program modules!
Do not go for less than this capacity. Not for today - and certainly not for tomorrow.
Beyond that, the console contains a BASIC interpreter for your own programs, as well as connectors for peripheral devices which allows you to tailor your video computer system TI99/4A as desired (and according to your requirements):
That way, a basic version can be set up from a TI99/4A, a color or B/W TV set (=monitor), and a cassette recorder. For the advanced version you need - besides the TI99/4A and the monitor - the Thermal Printer 32 [chars per line], a diskette control device, and the diskette drives 1 and/or 2. An office version may look like this: TI99/4A combined with a monitor, a normal-format printer, a V.24 [=RS232] interface, a diskette control device, and the diskette drive 1 (cf. page 6).
But, as said, you are the one to decide what video computer system TI99/4A shall run for you ...