As there was a multitude if Ikarus 543 models with different engines, this is a 1983 Ikarus 543.30 built on a MAN-VW 8.136 F chassis.
With different engines, different bodies and on different chassis. The 500 series was an umbrella designation for various small buses aimed at developing markets, made throughout the 80s and 90s. They were built on chassis from MAN, VW, Renault, Avia and other manufacturers.