To provide a cassette having stacked plug cavities with easy manufacturing without accompanied with degradation of a signal.

The cassette (20) is provided with a housing (30) having a front (34) and a rear (36). The housing includes a plurality of plug cavities (42) open at the front for receiving plugs therein, and a rear chamber (102) open to the plug cavities. The cassette also is provided with a contact subassembly (100) having a circuit board (104) and a plurality of contacts (144) arranged in a plurality of contact sets (146) coupled to the circuit board. Each contact set is configured to mate with a corresponding plug, The contact subassembly is inserted into the rear chamber such that the contact sets are received in different corresponding plug cavities. The circuit board is oriented generally parallel to the front of the housing when the contact subassembly is inserted into the rear chamber.