A communication device for receiving and sending data by modulating and demodulating an electromagnetic wave, comprising: electromagnetic-wave generating means for generating an RF (Radio Frequency) field by generating an electromagnetic wave; modulating means for sending data at any of a plurality of transfer rates by modulating the electromagnetic wave; demodulating means for obtaining data sent from another device at any of a plurality of transfer rates by demodulating a received electromagnetic wave; and detecting means (23, 25) for detecting the received electromagnetic wave; wherein the communication device is operable in each of a passive mode and active mode communication with the another device (2, 3), the passive mode providing a load modulated communication and the active mode including generation of electromagnetic waves by both the communication device and the another communication device (2, 3); characterized in that: the communication device is configured such that, if the detecting means (23, 25) does not detect the received electromagnetic wave at or above the level of a first threshold within a first time period, the communication device is operable to selectively initiate either the passive mode or active mode communication with the another device (2, 3)to obtain data from the another device (2, 3); and the communication device is configured such that, if the detecting means (23, 25) does detect the received electromagnetic wave at or above the level of a first threshold within the first time period, the communication device is operable to selectively initiate either active mode communication with the another device (2, 3) or the passive mode communication with the another device (2, 3) to act as a communication target for the another device (2, 3). electromagnetic-wave generating means for generating an RF (Radio Frequency) field by generating an electromagnetic wave; modulating means for sending data at any of a plurality of transfer rates by modulating the electromagnetic wave; demodulating means for obtaining data sent from another device at any of a plurality of transfer rates by demodulating a received electromagnetic wave; and detecting means (23, 25) for detecting the received electromagnetic wave; wherein the communication device is operable in each of a passive mode and active mode communication with the another device (2, 3), the passive mode providing a load modulated communication and the active mode including generation of electromagnetic waves by both the communication device and the another communication device (2, 3); characterized in that: the communication device is configured such that, if the detecting means (23, 25) does not detect the received electromagnetic wave at or above the level of a first threshold within a first time period, the communication device is operable to selectively initiate either the passive mode or active mode communication with the another device (2, 3)to obtain data from the another device (2, 3); and the communication device is configured such that, if the detecting means (23, 25) does detect the received electromagnetic wave at or above the level of a first threshold within the first time period, the communication device is operable to selectively initiate either active mode communication with the another device (2, 3) or the passive mode communication with the another device (2, 3) to act as a communication target for the another device (2, 3). the communication device is configured such that, if the detecting means (23, 25) does not detect the received electromagnetic wave at or above the level of a first threshold within a first time period, the communication device is operable to selectively initiate either the passive mode or active mode communication with the another device (2, 3)to obtain data from the another device (2, 3); and the communication device is configured such that, if the detecting means (23, 25) does detect the received electromagnetic wave at or above the level of a first threshold within the first time period, the communication device is operable to selectively initiate either active mode communication with the another device (2, 3) or the passive mode communication with the another device (2, 3) to act as a communication target for the another device (2, 3).