IBM produced a series of typewriters called Thermotronic with letter-quality output and correcting tape along with printers tagged Quietwriter. Brother extended the life of their typewriter product line with similar products. The development of these proprietary printing engines provided the vendors with exclusive markets in consumable ribbons and the ability to use standardized printing engines with varying degrees of electronic and software sophistication to develop product lines. Although these changes reduced prices—and greatly increased the convenience—of typewriters, the technological disruption posed by word processors left these improvements with only a short-term low-end market. To extend the life of these products, many examples were provided with communication ports to connect them to computers as printers.