9 electrical and electronic apparatus and instruments, namely switches and switching circuits, interface circuits, network management circuits, packet assemblers, packet disassemblers, terminal concentrators, buffer circuits, circuits allowing and/or controlling inter-communication between computers and/or between terminals, printed circuit boards, tapes disks, cards, wires and filaments, all being magnetic data carriers; data processors; computers and computer software for controlling switches and switching circuits; cash registers; point of sale terminals; bar code readers; and optical fibres