The Unicode character set contains all Vietnamese characters and the Vietnamese currency symbol. On systems that do not support Unicode, many 8-bit Vietnamese code pages are available such as Vietnamese Standard Code for Information Interchange (VSCII) or Windows-1258. Where ASCII must be used, Vietnamese letters are often typed using the VIQR convention, though this is largely unnecessary with the increasing ubiquity of Unicode. There are many software tools that help type Roman-script Vietnamese on English keyboards, such as WinVNKey and Unikey on Windows, or MacVNKey on Macintosh, with popular methods of encoding Vietnamese using Telex, VNI or VIQR input methods all included. Telex input method is often set as the default for many devices. Besides third-party software tools, operating systems such as Windows or macOS can also be installed with Vietnamese and Vietnamese keyboard, e.g. Vietnamese Telex in Microsoft Windows.