A telecommunications jack 1 is described that comprises a housing 2 defining a port for receiving a plug; contacts 7 for making an electrical connection with wires of a cable; interface contacts 4 for making an electrical connection with contacts of the plug; and a multilayer printed circuit board (PCB) 5 for electrically connecting the contacts 7 and the interface contacts 4. The multilayer PCB comprises a free-floating ground plane structure formed from two outer layers of the multilayer PCB and a plurality of internal layers 15B, 15C, 15D, 15E having a plurality of electronic devices 16, 17 disposed thereon. The two outer layers 15 of the multilayer PCB include a continuous coating 19 of electrically conductive material covering at least those parts of the PCB that include the electronic devices and wherein the two outer layers of the PCB are electrically connected with each other and are electrically isolated from the internal layers of the PCB.