The 3G shield is based on SIM5216E module. The SIM5216 series is Multi-Band HSDPA/WCDMA/GSM/GPRS/EDGE module solution which supports HSDPA up to 3.6Mbps for downlink data transfer. The 3G shield can be used for 3G communication, it is controlled via AT commands and fully compatible with Arduino.
Its includes external GSM antenna, audio circuit for connecting microphone, speaker, hands free and headphones sets and a SD socket to save directly all the data coming from the 3G network. You can even reproduce audio files stored in the SD card (like a mp3 player!).
You can also use it as a standard 3G modem at full speed (~7.2Mbps download, ~5.5Mbps upload) just connecting it through its specific mini-USB socket to your laptop (Linux, Windows, MacOS).
The new communicating module is specially oriented to work with Internet servers implementing internally several application layer protocols which make easier to send the information to the cloud. We can make HTTP and HTTPS (secure mode) navigation, downloading and uploading content to a web server. In the same way FTP and FTPS (secure mode) protocols are also available which is really useful when your application requires handling files. You can even send and receive mails directly from Arduino using the SMTP and POP3 clients implemented internally.
With the SD Card socket so you can handle a complete FAT16 file systems and store GB's of information. This specially useful as the 3G module can work at full speed (~7.2Mbps download, ~5.5Mbps upload) when working with the SD files directly without need of Arduino for data or files management.
Specifications for Data transfer: