The model currently called Ikarus 280 T should be renamed to Ikarus-Ganz 280 T. It's a trolley-bus made in collaboration with Ganz.
http://en.wikipedia.org/wiki/Ganz_Works

A proof that they are badged Ikarus-Ganz:
http://www.imcdb.org/vehicle_641826-Ikarus-280-T-28092-1985.html