Because most electronic instruments are designed in a modularized way, manufacturers often release a sound module version of their fully integrated instruments. For example, the 1980s-era DX-7 synthesizer/keyboard was also sold as a standalone "sound module", the TX-7. A sound module may have all the other features of the controller-equipped version, but it often has a smaller display or limited programming controls. In this case, instrument and other sounds can be loaded through MIDI or external media. In some cases, sound modules have expanded capacity for sounds in comparison to the controller-equipped version.