A method for communicating with a host, said method being carried out by a secure digital card, SD card, the SD card comprising a wireless Internet access processing function unit comprising a device management port and a modem port, the method comprising: obtaining configuration information of the device management port and the modem port of the wireless Internet access processing function unit, generating SD card partition information separately corresponding to the device management port and the modem port according to the configuration information; reporting the SD card partition information to a host side; receiving downlink interaction information from the host side encapsulated in a secure digital card interface format, decapsulating the downlink interaction information encapsulated in the secure digital card interface format, delivering the decapsulated downlink interaction information to a corresponding port; receiving uplink interaction information reported to the host side from the device management port and the modem port, encapsulating the received uplink interaction information in the secure digital card interface format, sending the encapsulated uplink interaction information to the host side; having a case in which the corresponding port is the device management port, the downlink interaction information from the host side comprises a device management command from the host side, and the uplink interaction information reported to the host side comprises a response to the device management command; and having a case in which the corresponding port is the modem port, the downlink interaction information from the host side comprises a modem command from the host side or data sent to an external network, and the uplink interaction information reported to the host side comprises a response to the modem command or data from the external network. obtaining configuration information of the device management port and the modem port of the wireless Internet access processing function unit, generating SD card partition information separately corresponding to the device management port and the modem port according to the configuration information; reporting the SD card partition information to a host side; receiving downlink interaction information from the host side encapsulated in a secure digital card interface format, decapsulating the downlink interaction information encapsulated in the secure digital card interface format, delivering the decapsulated downlink interaction information to a corresponding port; receiving uplink interaction information reported to the host side from the device management port and the modem port, encapsulating the received uplink interaction information in the secure digital card interface format, sending the encapsulated uplink interaction information to the host side; having a case in which the corresponding port is the device management port, the downlink interaction information from the host side comprises a device management command from the host side, and the uplink interaction information reported to the host side comprises a response to the device management command; and having a case in which the corresponding port is the modem port, the downlink interaction information from the host side comprises a modem command from the host side or data sent to an external network, and the uplink interaction information reported to the host side comprises a response to the modem command or data from the external network.