The Texas Instruments Hex-bus Interface was designed in 1982 and intended for commercial release in late 1983. It connected the console to peripherals via a high-speed serial link. Though it was prototypical to today's USB (plug and play, hot-swappable, etc.), it was never released, with only a small number of prototypes appearing in the hands of collectors after TI pulled out of the market.
Several Hex-bus peripherals were planned or produced. A WaferTape drive never made it past the prototype stage due to reliability issues with the tapes. The 5.25-inch Floppy drive also never made it past the prototype stage, even though it worked. Prototype DSDD disk controllers and Video controllers were also made. A 4-color Printer-Plotter, a 300-Baud Modem, RS-232 Interface, an 80 column thermal/ink printer, and a 2.8" "Quick Disk" drive were the only peripherals released in quantity, mostly for use with the TI CC-40. All Hex-bus peripherals could be used with a TI-99/4A when connected through the Hex-bus Interface, through direct connection to the TI-99/8, or through direct connection to the Texas Instruments Compact Computer 40.
- HX-1000 Printer/Plotter
- HX-1010 Printer 80
- HX-2000 Wafertape drive
- HX-3000 RS232 interface
- HX-3100 Modem
- HX-3200 Centronics Printer Interface
- Quick Disk QD-02