The article had some major gaffes. Teletypes never had a ball. The stationary platen models had type boxes and cylinders, but never balls.
replies(1):
> Selectric-based mechanisms were also widely used as terminals for computers, replacing both Teletypes and older typebar-based output devices. One popular example was the IBM 2741 terminal
> Teletypes (technically "teleprinters" - "teletype" was just the most popular brand name)