Method for assigning user selectable identification number to each one of a plurality of fixed terminals, in order to allow one or more portable terminals to select the desired user selectable identification number to receive the relevant data or audio signal from the corresponding fixed terminal via radio frequency communication standard, wherein said radio frequency communication standard comprises DECT - Digital Enhanced Cordless Telecommunications - standard protocol, and wherein said method comprises the following steps: A. setting said user selectable identification number information for each fixed terminals; B. transmitting, by each fixed terminal, a first broadcast control signal comprising a respective RFPI, Radio Fixed Part Identity, code of said DECT standard protocol, wherein said user selectable identification number is encoded in the last 8 bits of said RFPI code, corresponding to the Radio fixed Part Number, PPN; C. selecting by said portable terminal a fixed terminal by selecting the relevant user selectable identification number; D. periodically transmitting by each fixed terminal a second broadcast control signal comprising a verification code, wherein each verification code of each of said fixed terminal is univocally associated to each one of the user selectable identification numbers, so that in case of said fixed terminal does not transmit said second broadcast control signal after a predetermined time interval, said fixed terminal will be discarded by each one of said portable terminal (3,) by which said fixed terminal has been selected in said selecting step C; and E. confirming by said portable terminals whether the fixed terminal is the correct one, by matching said verification code received by said second broadcast control signal with the selected received selectable identification number associated to the selected fixed terminal, so that in case of the match is negative, said fixed terminal will be discarded by each one of said portable terminal. A. setting said user selectable identification number information for each fixed terminals; B. transmitting, by each fixed terminal, a first broadcast control signal comprising a respective RFPI, Radio Fixed Part Identity, code of said DECT standard protocol, wherein said user selectable identification number is encoded in the last 8 bits of said RFPI code, corresponding to the Radio fixed Part Number, PPN; C. selecting by said portable terminal a fixed terminal by selecting the relevant user selectable identification number; D. periodically transmitting by each fixed terminal a second broadcast control signal comprising a verification code, wherein each verification code of each of said fixed terminal is univocally associated to each one of the user selectable identification numbers, so that in case of said fixed terminal does not transmit said second broadcast control signal after a predetermined time interval, said fixed terminal will be discarded by each one of said portable terminal (3,) by which said fixed terminal has been selected in said selecting step C; and E. confirming by said portable terminals whether the fixed terminal is the correct one, by matching said verification code received by said second broadcast control signal with the selected received selectable identification number associated to the selected fixed terminal, so that in case of the match is negative, said fixed terminal will be discarded by each one of said portable terminal.