Just the built in TV-Tuner. I live in Europe, so SDTV is 576i. And the manual says, that both 576i and 480i are supported. But I think it’s just like your TV, that 480i/576i only work with the TV-Tuner or component input.
I don’t get what Samsung is doing. This TV comes with a composite input in 2015, my 20 year old Metz tube TV doesn’t have this obsolute input anymore. They add useless inputs nobody needed 20 years ago, but they cut costs by not supporting standart PAL and NTSC resolution on all inputs. This is ridiculous.