Robocoin said on Tuesday that later this month it will install the first automated teller machines in the United States that let users buy and sell bitcoin, the latest step into the mainstream for the digital currency. The kiosks, to be installed in Seattle, and Austin, Texas, are similar to ATMs but have scanners to read government-issued identification such as a drivers license or a passport to confirm users identities. Robocoin also is planning to install ATMs in Asia and Europe.