The classic method of cordless telephony was Cordless Telephony( CT) in its different variants. This technology was later replaced by the DECT standard. The handset, known as the Portable Unit( PU), contains the speech and hearing equipment, the dial keypad, some function keys, and the transmitting and receiving equipment for radio transmission between the handset and the fixed part( BS).
The transmitting power of a DECT handset is 250 mW. The range of a portable unit depends on the transmission type and external conditions: Indoors, the range is generally less than 100 m, outdoors up to 1,000 m. The SAR value for non-ionizing radiation is generally below 100 mW/kg body weight.