Abstract: For subscriber access, via optical fibre, to communications networks that offer various types of service by means of an optical access node (AN), connections between the optical network terminating units (ONT) unit to which the subscribers are connected, and the access node (AN) can be made with point-to-point or point-to-multipoint fibre optic links. The links between the access node (AN) and the switching centre (CE) are made via optical fibres through which pass the lightwave signals corresponding to a number of subscribers, multiplexed together by means of wavelength division multiplexing. This network permits access to all types of communications services in which each type of service employs a reserved wavelength for its connection between the access node (AN) and the optical network terminating equipment (ONT) unit. This reserved wavelength is fixed and depends only on the type of service.