Power symbol

Under IEC 60417, the international standard for symbols on equipment, a line inside a broken circle means standby (symbol 5009). The usual reading is binary: the stroke is 1, on, and the ring is 0, off.

These symbols reached Unicode after a campaign led by Terence Eden, a technologist in Britain. The proposal was accepted in February 2015, and the characters arrived in Unicode 9.0 the following year.