Proposed is a bit-interleaver for an optical line terminal of an optical access network. The bit-interleaver contains a memory reader, that provides data streams at bit level to a space-time switch. The space-time switch reads within one input cycle up to N bit sets from the data streams. The switch switches within one writing cycle up to N bits onto up to its output ports, which provide respective output vectors. A number of N OR-function elements determine within the writing cycle respective single output bits. A number of N memory elements write within the one writing cycle a respective one of the output bits into a respective one of their bit sub-elements. A control unit that controls the reading of the data streams and also the switching of the bits by the switch. The control unit controls a choice of the writing addresses.