This paper describes the performance of a 560 Mbls digital fibre-optic link designed specifically for possible use in a broadband integrated services digital network (BISDN) environment. Four 140 Mbl s non-return-to-zero (NRZ) channels are time division multiplexed using a bit-by-bit multiplexing strategy and transmitted using potentially low cost 1.3 pm EE-LED and laser sources. A bit error rate with a power level of -34 dBm was achieved for each independent channel over a distance of 10 km. KEY WORDS Broadband subscriber loop Fibre optics Broadband integrated services digital network (BISDN) Synchronous optical network (SONET)