Universal Stylus Initiative
The Universal Stylus Initiative (USI) is a non-profit alliance of companies promoting a proprietary technical standard for interoperable active pen styluses on touchscreen devices such as phones, tablets, and computers. It defines a two-way communications protocol between the stylus and the computer and allows the stylus to remember user preferences for ink color and stroke. Multiple styluses can simultaneously draw on a single device. It support 9-axis inertial measurement. As of 2020, access to the specification is only available to members, but the goal is to create an open, non-proprietary active stylus specification  with a certification program for members. As of 2019, there were over 30 members including Google and 3M, but some major players like Apple and Microsoft had not joined. Products started coming to market in 2019 including one stylus and several Chromebooks from different manufacturers. As of 2021, the range of supported devices was increasing.