the possible connections i e bookkeeping in decision 124 a determination is made as to whether 1 the connection request is received at the first layer and 2 the connection request was not received directly from a portable communication unit if the determination of decision 124 is affirmative the called party is paged if it is a portable or rung if it is a fixed telephone step 126 in decision 128 it is determined whether a connection confirmation signal is received from the called communication unit within a predetermined period of time if the determination made in decision 128 is affirmative the connection is successful step 130 if it is negative the connection attempt fails step 132 if the determination in decision 124 is negative then a further decision 134 is made to determine whether the connection request was received in the first layer if decision 134 is affirmative the connection request is passed to its parent node in layer two step 136 the process then continues to the stop step 144 for that node if decision 134 is negative a further decision 138 is made to determine whether there is any information relating to the called party in the database corresponding.