A functional module in the field of telecommunications has a front, a rear and four side faces, more than two first contacts and more than two second contacts, each first contact being connected with a second contact, the contacts being adapted to be connected with first and second contacts of at least one contact module. Contacts are adapted to connect wires therewith so as to establish electrical connection between the contacts of the functional module and the contacts of the contact module. In addition, a telecommunications module includes at least one functional module and at least one contact module. An assembly of two or more telecommunications modules and a kit of parts are described. A method of installing a telecommunications module include installing a contact module then fitting a functional module to the contact module.